refactormain

185 files changed, 672 insertions, 584 deletions

diff --git a/lib/acceleration_bands.c b/lib/acceleration_bands.c
index 776b990..19c174a 100644
--- a/lib/acceleration_bands.c
+++ b/lib/acceleration_bands.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_acceleration_bands_p = { .n_inputs = 4, .n_outputs = 3,
 uint_t ts_acceleration_bands_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_acceleration_bands_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_acceleration_bands_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_acceleration_bands(
@@ -33,9 +33,11 @@ int ts_acceleration_bands(
 {
 	TS_PROLOGUE( ts_acceleration_bands_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_acceleration_bands_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+    uint_t k = ((ts_acceleration_bands_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
+    if (n > SIZE_MAX / sizeof( fp_t )) return -1;
     fp_t *hh_r = malloc( n * sizeof( fp_t ) );
     fp_t *ll_r = malloc( n * sizeof( fp_t ) );
     fp_t *tp = malloc( n * sizeof( fp_t ) );
diff --git a/lib/ad.c b/lib/ad.c
index fd0e40e..875f827 100644
--- a/lib/ad.c
+++ b/lib/ad.c
@@ -27,7 +27,6 @@ int ts_ad(
 {
 	TS_PROLOGUE( ts_ad_p );
 	(void)c;
-    if( n == 0 ) return -1;
 
     fp_t hl0 = ts_h( x, 0 ) - ts_l( x, 0 );
     y[0][0] = hl0 != 0
diff --git a/lib/ad_oscillator.c b/lib/ad_oscillator.c
index 5021140..66ca3cf 100644
--- a/lib/ad_oscillator.c
+++ b/lib/ad_oscillator.c
@@ -31,10 +31,9 @@ int ts_ad_oscillator(
 {
 	TS_PROLOGUE( ts_ad_oscillator_p );
 	if ( !c ) return -1;
-    if( n == 0 ) return -1;
 
-    fp_t fast = ((ts_ad_oscillator_params_t *)c)->fast;
-    fp_t slow = ((ts_ad_oscillator_params_t *)c)->slow;
+    fp_t fast = ((ts_ad_oscillator_params_t const *)c)->fast;
+    fp_t slow = ((ts_ad_oscillator_params_t const *)c)->slow;
     if (fast == 0 || slow == 0) return -1;
     fp_t a_fast = 1.0 / fast;
     fp_t a_slow = 1.0 / slow;
diff --git a/lib/adx.c b/lib/adx.c
index 505732b..a6700cf 100644
--- a/lib/adx.c
+++ b/lib/adx.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_adx_p = { .n_inputs = 4, .n_outputs = 4, .n_constants =
 uint_t ts_adx_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_adx_params_t *)c)->k + 1 : 0 );
+	return ( c ? ((ts_adx_params_t const *)c)->k + 1 : 0 );
 }
 
 int ts_adx(
@@ -36,7 +36,7 @@ int ts_adx(
 	TS_PROLOGUE( ts_adx_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_adx_params_t *)c)->k;
+	uint_t k = ((ts_adx_params_t const *)c)->k;
 	if (k == 0) return -1;
 
 	fp_t ema_plus = 0, ema_minus = 0, ema_tr = 0;
diff --git a/lib/alligator.c b/lib/alligator.c
index 81450b0..a74602c 100644
--- a/lib/alligator.c
+++ b/lib/alligator.c
@@ -28,7 +28,6 @@ int ts_alligator(
 {
 	TS_PROLOGUE( ts_alligator_p );
 	(void)c;
-    if( n == 0 ) return -1;
     /* Jaw: SMA(13) shifted 8 positions */
     /* Teeth: SMA(8) shifted 5 positions */
     /* Lips: SMA(5) shifted 3 positions */
diff --git a/lib/annualized_historical_volatility.c b/lib/annualized_historical_volatility.c
index c0c88cf..27ed0f0 100644
--- a/lib/annualized_historical_volatility.c
+++ b/lib/annualized_historical_volatility.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_annualized_historical_volatility_p = { .n_inputs = 1, .n
 uint_t ts_annualized_historical_volatility_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_annualized_historical_volatility_params_t *)c)->k : 0 );
+	return ( c ? ((ts_annualized_historical_volatility_params_t const *)c)->k : 0 );
 }
 
 int ts_annualized_historical_volatility(
@@ -31,9 +31,13 @@ int ts_annualized_historical_volatility(
 {
 	TS_PROLOGUE( ts_annualized_historical_volatility_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_annualized_historical_volatility_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+    uint_t k = ((ts_annualized_historical_volatility_params_t const *)c)->k;
     if (k == 0 || n <= k) return -1;
 
+    for ( uint_t i = 0; i < k; ++i )
+        y[0][i] = NAN;
+
     /* Compute log returns, then stddev, then annualize */
     for (uint_t i = k; i < n; ++i)
     {
diff --git a/lib/apo.c b/lib/apo.c
index f888162..fa720a7 100644
--- a/lib/apo.c
+++ b/lib/apo.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_apo_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_apo_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? (uint_t)((ts_apo_params_t *)c)->slow_k - 1 : 0 );
+	return ( c ? (uint_t)((ts_apo_params_t const *)c)->slow_k - 1 : 0 );
 }
 
 int ts_apo(
@@ -31,10 +31,9 @@ int ts_apo(
 {
 	TS_PROLOGUE( ts_apo_p );
 	if ( !c ) return -1;
-	if (n == 0) return -1;
 
-	fp_t fast_k = ((ts_apo_params_t *)c)->fast_k;
-	fp_t slow_k = ((ts_apo_params_t *)c)->slow_k;
+	fp_t fast_k = ((ts_apo_params_t const *)c)->fast_k;
+	fp_t slow_k = ((ts_apo_params_t const *)c)->slow_k;
 	if (fast_k == 0 || slow_k == 0) return -1;
 
    fp_t fast_a = 1.0 / fast_k;
diff --git a/lib/aroon.c b/lib/aroon.c
index 539e97b..1bf824b 100644
--- a/lib/aroon.c
+++ b/lib/aroon.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_aroon_p = { .n_inputs = 4, .n_outputs = 2, .n_constants
 uint_t ts_aroon_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_aroon_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_aroon_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_aroon(
@@ -32,7 +32,7 @@ int ts_aroon(
 {
 	TS_PROLOGUE( ts_aroon_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_aroon_params_t *)c)->k;
+    uint_t k = ((ts_aroon_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for ( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/aroon_oscillator.c b/lib/aroon_oscillator.c
index db9fe9d..2152655 100644
--- a/lib/aroon_oscillator.c
+++ b/lib/aroon_oscillator.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_aroon_oscillator_p = { .n_inputs = 4, .n_outputs = 1, .n
 uint_t ts_aroon_oscillator_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_aroon_oscillator_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_aroon_oscillator_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_aroon_oscillator(
@@ -32,7 +32,7 @@ int ts_aroon_oscillator(
 {
 	TS_PROLOGUE( ts_aroon_oscillator_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_aroon_oscillator_params_t *)c)->k;
+    uint_t k = ((ts_aroon_oscillator_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for ( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/asi.c b/lib/asi.c
index ac4225b..e0132e8 100644
--- a/lib/asi.c
+++ b/lib/asi.c
@@ -28,7 +28,6 @@ int ts_asi(
 {
 	TS_PROLOGUE( ts_asi_p );
 	(void)c;
-    if( n == 0 ) return -1;
 
     y[0][0] = 0;
 
diff --git a/lib/atr.c b/lib/atr.c
index 7c9f06f..7444531 100644
--- a/lib/atr.c
+++ b/lib/atr.c
@@ -26,7 +26,7 @@ ts_parameter_t const ts_atr_p = { .n_inputs = 4, .n_outputs = 1, .n_constants =
 uint_t ts_atr_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_atr_params_t *)c)->k : 0 );
+	return ( c ? ((ts_atr_params_t const *)c)->k : 0 );
 }
 
 int ts_atr(
@@ -38,7 +38,7 @@ int ts_atr(
 	TS_PROLOGUE( ts_atr_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_atr_params_t *)c)->k;
+	uint_t k = ((ts_atr_params_t const *)c)->k;
 	if (k == 0) return -1;
 	if (n < 2) return -1;
 
diff --git a/lib/atr_bands.c b/lib/atr_bands.c
index 73b7d44..1aa7464 100644
--- a/lib/atr_bands.c
+++ b/lib/atr_bands.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_atr_bands_p = { .n_inputs = 4, .n_outputs = 3, .n_consta
 uint_t ts_atr_bands_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_atr_bands_params_t *)c)->k : 0 );
+	return ( c ? ((ts_atr_bands_params_t const *)c)->k : 0 );
 }
 
 int ts_atr_bands(
@@ -36,11 +36,20 @@ int ts_atr_bands(
 {
 	TS_PROLOGUE( ts_atr_bands_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_atr_bands_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_atr_bands_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 	if (n < 2) return -1;
 
-	fp_t mult = ((ts_atr_bands_params_t *)c)->mult;
+	fp_t mult = ((ts_atr_bands_params_t const *)c)->mult;
+	if (mult < 0 || isnan(mult) || isinf(mult)) return -1;
+
+	for ( uint_t i = 0; i < k - 1; ++i )
+	{
+		y[0][i] = NAN;
+		y[1][i] = NAN;
+		y[2][i] = NAN;
+	}
 
 	fp_t tr_sum = 0;
 	fp_t atr = 0;
diff --git a/lib/atr_trailing_stops.c b/lib/atr_trailing_stops.c
index 2c7cd73..46628a2 100644
--- a/lib/atr_trailing_stops.c
+++ b/lib/atr_trailing_stops.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_atr_trailing_stops_p = { .n_inputs = 4, .n_outputs = 2,
 uint_t ts_atr_trailing_stops_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_atr_trailing_stops_params_t *)c)->k : 0 );
+	return ( c ? ((ts_atr_trailing_stops_params_t const *)c)->k : 0 );
 }
 
 int ts_atr_trailing_stops(
@@ -35,11 +35,19 @@ int ts_atr_trailing_stops(
 {
 	TS_PROLOGUE( ts_atr_trailing_stops_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_atr_trailing_stops_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_atr_trailing_stops_params_t const *)c)->k;
 	if (k == 0) return -1;
 	if (n < k + 1) return -1;
 
-	fp_t mult = ((ts_atr_trailing_stops_params_t *)c)->mult;
+	fp_t mult = ((ts_atr_trailing_stops_params_t const *)c)->mult;
+	if (mult < 0 || isnan(mult) || isinf(mult)) return -1;
+
+	for ( uint_t i = 0; i < k; ++i )
+	{
+		y[0][i] = NAN;
+		y[1][i] = NAN;
+	}
 
 	fp_t tr_sum = 0;
 	fp_t atr = 0;
diff --git a/lib/average.c b/lib/average.c
index 391de93..ece89ca 100644
--- a/lib/average.c
+++ b/lib/average.c
@@ -33,7 +33,7 @@ ts_parameter_t const ts_average_p = { .n_inputs = 1, .n_outputs = 1, .n_constant
 uint_t ts_average_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_average_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_average_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_average(
@@ -45,7 +45,7 @@ int ts_average(
 	TS_PROLOGUE( ts_average_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_average_params_t *)c)->k;
+	uint_t k = ((ts_average_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/average_exponential.c b/lib/average_exponential.c
index bae9d5f..1875bc3 100644
--- a/lib/average_exponential.c
+++ b/lib/average_exponential.c
@@ -40,7 +40,7 @@ int ts_average_exponential(
 	TS_PROLOGUE( ts_average_exponential_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	fp_t k = ((ts_average_exponential_params_t *)c)->k;
+	fp_t k = ((ts_average_exponential_params_t const *)c)->k;
 	if (k <= 0 || isnan(k)) return -1;
 
 	fp_t a = 1.0 / k;
diff --git a/lib/average_exponential_double.c b/lib/average_exponential_double.c
index eeb890f..5c3dcb4 100644
--- a/lib/average_exponential_double.c
+++ b/lib/average_exponential_double.c
@@ -35,8 +35,8 @@ int ts_average_exponential_double(
 	TS_PROLOGUE( ts_average_exponential_double_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	fp_t a = ((ts_average_exponential_double_params_t *)c)->a;
-	if (a == 0 || n == 0) return -1;
+	fp_t a = ((ts_average_exponential_double_params_t const *)c)->a;
+	if (a == 0) return -1;
 
 	fp_t ema1 = x[0][0];
 	fp_t ema2 = x[0][0];
diff --git a/lib/average_exponential_triple.c b/lib/average_exponential_triple.c
index 467d87f..793d048 100644
--- a/lib/average_exponential_triple.c
+++ b/lib/average_exponential_triple.c
@@ -33,8 +33,8 @@ int ts_average_exponential_triple(
 	TS_PROLOGUE( ts_average_exponential_triple_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	fp_t a = ((ts_average_exponential_triple_params_t *)c)->a;
-	if (a == 0 || n == 0) return -1;
+	fp_t a = ((ts_average_exponential_triple_params_t const *)c)->a;
+	if (a == 0) return -1;
 
 	fp_t ema1 = x[0][0];
 	fp_t ema2 = x[0][0];
diff --git a/lib/average_triangle.c b/lib/average_triangle.c
index 9ac952d..fd1c037 100644
--- a/lib/average_triangle.c
+++ b/lib/average_triangle.c
@@ -29,7 +29,7 @@ ts_parameter_t const ts_average_triangle_p = { .n_inputs = 1, .n_outputs = 1, .n
 uint_t ts_average_triangle_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? 2 * ( ((ts_average_triangle_params_t *)c)->k - 1 ) : 0 );
+	return ( c ? 2 * ( ((ts_average_triangle_params_t const *)c)->k - 1 ) : 0 );
 }
 
 int ts_average_triangle(
@@ -40,7 +40,7 @@ int ts_average_triangle(
 {
 	TS_PROLOGUE( ts_average_triangle_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_average_triangle_params_t *)c)->k;
+	uint_t k = ((ts_average_triangle_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	fp_t rk2 = _ts_reciprocal( _ts_square( k ) );
diff --git a/lib/average_weighted.c b/lib/average_weighted.c
index eb99a17..632de8b 100644
--- a/lib/average_weighted.c
+++ b/lib/average_weighted.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_average_weighted_p = { .n_inputs = 1, .n_outputs = 1, .n
 uint_t ts_average_weighted_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_average_weighted_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_average_weighted_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_average_weighted(
@@ -35,7 +35,7 @@ int ts_average_weighted(
 {
 	TS_PROLOGUE( ts_average_weighted_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_average_weighted_params_t *)c)->k;
+	uint_t k = ((ts_average_weighted_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/average_weighted_series.c b/lib/average_weighted_series.c
index d7e2ccb..d388651 100644
--- a/lib/average_weighted_series.c
+++ b/lib/average_weighted_series.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_average_weighted_series_p = { .n_inputs = 2, .n_outputs
 uint_t ts_average_weighted_series_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_average_weighted_series_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_average_weighted_series_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_average_weighted_series(
@@ -34,7 +34,7 @@ int ts_average_weighted_series(
 {
 	TS_PROLOGUE( ts_average_weighted_series_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_average_weighted_series_params_t *)c)->k;
+	uint_t k = ((ts_average_weighted_series_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/band_width.c b/lib/band_width.c
index 822d835..4a4d6cb 100644
--- a/lib/band_width.c
+++ b/lib/band_width.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_band_width_p = { .n_inputs = 1, .n_outputs = 1, .n_const
 uint_t ts_band_width_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_band_width_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_band_width_params_t const *)c)->k > 0 ? ((ts_band_width_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_band_width(
@@ -32,9 +32,11 @@ int ts_band_width(
 {
 	TS_PROLOGUE( ts_band_width_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_band_width_params_t *)c)->k;
-    fp_t std_mult = ((ts_band_width_params_t *)c)->std_mult;
+	TS_CHECK_INPUT(x, x_n, n);
+    uint_t k = ((ts_band_width_params_t const *)c)->k;
+    fp_t std_mult = ((ts_band_width_params_t const *)c)->std_mult;
     if (k == 0 || n < k) return -1;
+    if (std_mult < 0 || isnan(std_mult) || isinf(std_mult)) return -1;
 
     for (uint_t i = k - 1; i < n; ++i)
     {
diff --git a/lib/beta_pdf.c b/lib/beta_pdf.c
index a23ed68..1366665 100644
--- a/lib/beta_pdf.c
+++ b/lib/beta_pdf.c
@@ -32,8 +32,8 @@ int ts_beta_pdf(
 {
 	TS_PROLOGUE( ts_beta_pdf_p );
 	if ( !c ) return -1;
-	fp_t alpha = ((ts_beta_pdf_params_t *)c)->alpha;
-	fp_t beta = ((ts_beta_pdf_params_t *)c)->beta;
+	fp_t alpha = ((ts_beta_pdf_params_t const *)c)->alpha;
+	fp_t beta = ((ts_beta_pdf_params_t const *)c)->beta;
 	if (isnan(alpha) || isnan(beta) || alpha <= 0 || beta <= 0)
 	{
 		for( uint_t i = 0; i < n; ++i ) y[0][i] = 0;
diff --git a/lib/binomial_pdf.c b/lib/binomial_pdf.c
index 8b3a442..f10663f 100644
--- a/lib/binomial_pdf.c
+++ b/lib/binomial_pdf.c
@@ -32,8 +32,8 @@ int ts_binomial_pdf(
 {
 	TS_PROLOGUE( ts_binomial_pdf_p );
 	if ( !c ) return -1;
-	uint_t n_trials = ((ts_binomial_pdf_params_t *)c)->n_trials;
-	fp_t p = ((ts_binomial_pdf_params_t *)c)->p;
+	uint_t n_trials = ((ts_binomial_pdf_params_t const *)c)->n_trials;
+	fp_t p = ((ts_binomial_pdf_params_t const *)c)->p;
 	if (p < 0.0 || p > 1.0 || isnan(p) || isinf(p)) return -1;
 	for( uint_t i = 0; i < n; ++i )
 	{
diff --git a/lib/bollinger_bands.c b/lib/bollinger_bands.c
index 55da054..56ce8f9 100644
--- a/lib/bollinger_bands.c
+++ b/lib/bollinger_bands.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_bollinger_bands_p = { .n_inputs = 1, .n_outputs = 3, .n_
 uint_t ts_bollinger_bands_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_bollinger_bands_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_bollinger_bands_params_t const *)c)->k > 0 ? ((ts_bollinger_bands_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_bollinger_bands(
@@ -37,10 +37,17 @@ int ts_bollinger_bands(
 	TS_PROLOGUE( ts_bollinger_bands_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_bollinger_bands_params_t *)c)->k;
+	uint_t k = ((ts_bollinger_bands_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
-	fp_t std_mult = ((ts_bollinger_bands_params_t *)c)->std_mult;
-	if (std_mult < 0 || isnan(std_mult)) return -1;
+	fp_t std_mult = ((ts_bollinger_bands_params_t const *)c)->std_mult;
+	if (std_mult < 0 || isnan(std_mult) || isinf(std_mult)) return -1;
+
+	for( uint_t i = 0; i < k - 1; ++i )
+	{
+		y[0][i] = NAN;
+		y[1][i] = NAN;
+		y[2][i] = NAN;
+	}
 
 	// Two-pass initial window for numerical stability
 	{
@@ -56,8 +63,8 @@ int ts_bollinger_bands(
 		}
 		variance /= (fp_t)k;
 		fp_t stddev = sqrt( variance );
-		y[1][k - 1] = mean + std_mult * stddev;
-		y[0][k - 1] = mean;
+		y[0][k - 1] = mean + std_mult * stddev;
+		y[1][k - 1] = mean;
 		y[2][k - 1] = mean - std_mult * stddev;
 	}
 
@@ -79,8 +86,8 @@ int ts_bollinger_bands(
 		}
 		variance *= rk;
 		fp_t stddev = sqrt( variance );
-		y[1][i] = mean + std_mult * stddev;
-		y[0][i] = mean;
+		y[0][i] = mean + std_mult * stddev;
+		y[1][i] = mean;
 		y[2][i] = mean - std_mult * stddev;
 	}
 	return 0;
diff --git a/lib/bollinger_lower.c b/lib/bollinger_lower.c
index 05a0883..3eac1f0 100644
--- a/lib/bollinger_lower.c
+++ b/lib/bollinger_lower.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_bollinger_lower_p = { .n_inputs = 1, .n_outputs = 1, .n_
 uint_t ts_bollinger_lower_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_bollinger_lower_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_bollinger_lower_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_bollinger_lower(
@@ -34,9 +34,9 @@ int ts_bollinger_lower(
 {
 	TS_PROLOGUE( ts_bollinger_lower_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_bollinger_lower_params_t *)c)->k;
+	uint_t k = ((ts_bollinger_lower_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
-	fp_t std_mult = ((ts_bollinger_lower_params_t *)c)->std_mult;
+	fp_t std_mult = ((ts_bollinger_lower_params_t const *)c)->std_mult;
 	if (isnan(std_mult) || isinf(std_mult)) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/bollinger_pctb.c b/lib/bollinger_pctb.c
index a3425cd..6387f16 100644
--- a/lib/bollinger_pctb.c
+++ b/lib/bollinger_pctb.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_bollinger_pctb_p = { .n_inputs = 1, .n_outputs = 1, .n_c
 uint_t ts_bollinger_pctb_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_bollinger_pctb_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_bollinger_pctb_params_t const *)c)->k > 0 ? ((ts_bollinger_pctb_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_bollinger_pctb(
@@ -34,10 +34,11 @@ int ts_bollinger_pctb(
 {
 	TS_PROLOGUE( ts_bollinger_pctb_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_bollinger_pctb_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_bollinger_pctb_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
-	fp_t std_mult = ((ts_bollinger_pctb_params_t *)c)->std_mult;
-	if (isnan(std_mult) || isinf(std_mult)) return -1;
+	fp_t std_mult = ((ts_bollinger_pctb_params_t const *)c)->std_mult;
+	if (std_mult < 0 || isnan(std_mult) || isinf(std_mult)) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
 	{
diff --git a/lib/bollinger_upper.c b/lib/bollinger_upper.c
index 9294cfb..51ced24 100644
--- a/lib/bollinger_upper.c
+++ b/lib/bollinger_upper.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_bollinger_upper_p = { .n_inputs = 1, .n_outputs = 1, .n_
 uint_t ts_bollinger_upper_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_bollinger_upper_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_bollinger_upper_params_t const *)c)->k > 0 ? ((ts_bollinger_upper_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_bollinger_upper(
@@ -34,10 +34,11 @@ int ts_bollinger_upper(
 {
 	TS_PROLOGUE( ts_bollinger_upper_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_bollinger_upper_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_bollinger_upper_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
-	fp_t std_mult = ((ts_bollinger_upper_params_t *)c)->std_mult;
-	if (isnan(std_mult) || isinf(std_mult)) return -1;
+	fp_t std_mult = ((ts_bollinger_upper_params_t const *)c)->std_mult;
+	if (std_mult < 0 || isnan(std_mult) || isinf(std_mult)) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
 	{
diff --git a/lib/bollinger_width.c b/lib/bollinger_width.c
index d9bca25..00891ce 100644
--- a/lib/bollinger_width.c
+++ b/lib/bollinger_width.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_bollinger_width_p = { .n_inputs = 1, .n_outputs = 1, .n_
 uint_t ts_bollinger_width_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_bollinger_width_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_bollinger_width_params_t const *)c)->k > 0 ? ((ts_bollinger_width_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_bollinger_width(
@@ -34,10 +34,11 @@ int ts_bollinger_width(
 {
 	TS_PROLOGUE( ts_bollinger_width_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_bollinger_width_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_bollinger_width_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
-	fp_t std_mult = ((ts_bollinger_width_params_t *)c)->std_mult;
-	if (isnan(std_mult) || isinf(std_mult)) return -1;
+	fp_t std_mult = ((ts_bollinger_width_params_t const *)c)->std_mult;
+	if (std_mult < 0 || isnan(std_mult) || isinf(std_mult)) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
 	{
diff --git a/lib/cci.c b/lib/cci.c
index 956f619..5345ac8 100644
--- a/lib/cci.c
+++ b/lib/cci.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_cci_p = { .n_inputs = 4, .n_outputs = 1, .n_constants =
 uint_t ts_cci_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_cci_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_cci_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_cci(
@@ -32,7 +32,7 @@ int ts_cci(
 	TS_PROLOGUE( ts_cci_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_cci_params_t *)c)->k;
+	uint_t k = ((ts_cci_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	// Compute initial typical prices
diff --git a/lib/center_of_gravity.c b/lib/center_of_gravity.c
index 3186c44..ae78bdc 100644
--- a/lib/center_of_gravity.c
+++ b/lib/center_of_gravity.c
@@ -19,7 +19,7 @@ ts_parameter_t const ts_center_of_gravity_p = { .n_inputs = 1, .n_outputs = 1, .
 uint_t ts_center_of_gravity_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_center_of_gravity_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_center_of_gravity_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_center_of_gravity(
@@ -30,7 +30,7 @@ int ts_center_of_gravity(
 {
 	TS_PROLOGUE( ts_center_of_gravity_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_center_of_gravity_params_t *)c)->k;
+	uint_t k = ((ts_center_of_gravity_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/chande_forecast_oscillator.c b/lib/chande_forecast_oscillator.c
index 6e65bbe..c3b2c8c 100644
--- a/lib/chande_forecast_oscillator.c
+++ b/lib/chande_forecast_oscillator.c
@@ -19,7 +19,7 @@ ts_parameter_t const ts_chande_forecast_oscillator_p = { .n_inputs = 1, .n_outpu
 uint_t ts_chande_forecast_oscillator_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_chande_forecast_oscillator_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_chande_forecast_oscillator_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_chande_forecast_oscillator(
@@ -30,7 +30,7 @@ int ts_chande_forecast_oscillator(
 {
 	TS_PROLOGUE( ts_chande_forecast_oscillator_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_chande_forecast_oscillator_params_t *)c)->k;
+	uint_t k = ((ts_chande_forecast_oscillator_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/change.c b/lib/change.c
index 84815a5..8e4c1b2 100644
--- a/lib/change.c
+++ b/lib/change.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_change_p = { .n_inputs = 1, .n_outputs = 1, .n_constants
 uint_t ts_change_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_change_params_t *)c)->k : 0 );
+	return ( c ? ((ts_change_params_t const *)c)->k : 0 );
 }
 
 int ts_change(
@@ -31,7 +31,7 @@ int ts_change(
 {
 	TS_PROLOGUE( ts_change_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_change_params_t *)c)->k;
+	uint_t k = ((ts_change_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k; i < n; ++i )
diff --git a/lib/channel.c b/lib/channel.c
index a2d8bd9..9fbd0e3 100644
--- a/lib/channel.c
+++ b/lib/channel.c
@@ -19,7 +19,7 @@ ts_parameter_t const ts_channel_p = { .n_inputs = 4, .n_outputs = 2, .n_constant
 uint_t ts_channel_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_channel_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_channel_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_channel(
@@ -30,7 +30,7 @@ int ts_channel(
 {
 	TS_PROLOGUE( ts_channel_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_channel_params_t *)c)->k;
+	uint_t k = ((ts_channel_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = k - 1;
diff --git a/lib/chebyshev_t.c b/lib/chebyshev_t.c
index a0230b8..5428fa4 100644
--- a/lib/chebyshev_t.c
+++ b/lib/chebyshev_t.c
@@ -28,32 +28,32 @@ int ts_chebyshev_t(
 {
 	TS_PROLOGUE( ts_chebyshev_t_p );
 	(void)c;
-    for( uint_t i = 0; i < n; ++i )
-    {
-        fp_t xv = x[0][i];
-        uint_t n_val = (uint_t)x[1][i];
-        if (x[1][i] < 0 || x[1][i] > 10000) { y[0][i] = 0; continue; }
-        if( n_val == 0 )
-        {
-            y[0][i] = 1.0;
-        }
-        else if( n_val == 1 )
-        {
-            y[0][i] = xv;
-        }
-        else
-        {
-            fp_t t0 = 1.0;
-            fp_t t1 = xv;
-            for( uint_t k = 2; k <= n_val; ++k )
-            {
-                fp_t t2 = 2.0 * xv * t1 - t0;
-                t0 = t1;
-                t1 = t2;
-            }
-            y[0][i] = t1;
-        }
-    }
+ for( uint_t i = 0; i < n; ++i )
+	{
+		fp_t xv = x[0][i];
+		uint_t n_val = (uint_t)x[1][i];
+		if (x[1][i] < 0 || x[1][i] > 10000) { y[0][i] = 0; continue; }
+		if( n_val == 0 )
+		{
+			y[0][i] = 1.0;
+		}
+		else if( n_val == 1 )
+		{
+			y[0][i] = xv;
+		}
+		else
+		{
+			fp_t t0 = 1.0;
+			fp_t t1 = xv;
+			for( uint_t k = 2; k <= n_val; ++k )
+			{
+				fp_t t2 = 2.0 * xv * t1 - t0;
+				t0 = t1;
+				t1 = t2;
+			}
+			y[0][i] = t1;
+		}
+	}
 	return 0;
 }
 
diff --git a/lib/chi_squared_pdf.c b/lib/chi_squared_pdf.c
index 7f2ba09..7a3c7df 100644
--- a/lib/chi_squared_pdf.c
+++ b/lib/chi_squared_pdf.c
@@ -31,7 +31,7 @@ int ts_chi_squared_pdf(
 {
 	TS_PROLOGUE( ts_chi_squared_pdf_p );
 	if ( !c ) return -1;
-	fp_t k = ((ts_chi_squared_pdf_params_t *)c)->k;
+	fp_t k = ((ts_chi_squared_pdf_params_t const *)c)->k;
 	if ( k <= 0 )
 	{
 		for( uint_t i = 0; i < n; ++i ) y[0][i] = 0;
diff --git a/lib/choppiness_index.c b/lib/choppiness_index.c
index 55ecb46..332e8b3 100644
--- a/lib/choppiness_index.c
+++ b/lib/choppiness_index.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_choppiness_index_p = { .n_inputs = 3, .n_outputs = 1, .n
 uint_t ts_choppiness_index_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? 2 * ((ts_choppiness_index_params_t *)c)->k : 0 );
+	return ( c ? 2 * ((ts_choppiness_index_params_t const *)c)->k : 0 );
 }
 
 int ts_choppiness_index(
@@ -31,7 +31,7 @@ int ts_choppiness_index(
 {
 	TS_PROLOGUE( ts_choppiness_index_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_choppiness_index_params_t *)c)->k;
+    uint_t k = ((ts_choppiness_index_params_t const *)c)->k;
     uint_t range_period = 2 * k;
     if (k == 0 || n < range_period) return -1;
 
diff --git a/lib/close_to_high.c b/lib/close_to_high.c
index dc7cf7b..a4c15f4 100644
--- a/lib/close_to_high.c
+++ b/lib/close_to_high.c
@@ -8,7 +8,6 @@
 // Outputs:   1 (ratio)
 // Constants: 0
 
-#include <math.h>
 #include "ts.h"
 
 
diff --git a/lib/close_to_open_ratio.c b/lib/close_to_open_ratio.c
index d857dd2..466b5e1 100644
--- a/lib/close_to_open_ratio.c
+++ b/lib/close_to_open_ratio.c
@@ -8,7 +8,6 @@
 // Outputs:   1 (ratio)
 // Constants: 0
 
-#include <math.h>
 #include "ts.h"
 
 
diff --git a/lib/cmf.c b/lib/cmf.c
index 7ac0402..52fa7c6 100644
--- a/lib/cmf.c
+++ b/lib/cmf.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_cmf_p = { .n_inputs = 5, .n_outputs = 1, .n_constants =
 uint_t ts_cmf_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_cmf_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_cmf_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_cmf(
@@ -31,7 +31,7 @@ int ts_cmf(
 {
 	TS_PROLOGUE( ts_cmf_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_cmf_params_t *)c)->k;
+    uint_t k = ((ts_cmf_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_mf = 0;
diff --git a/lib/cmo.c b/lib/cmo.c
index 9db5622..4c7598c 100644
--- a/lib/cmo.c
+++ b/lib/cmo.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_cmo_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_cmo_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_cmo_params_t *)c)->k : 0 );
+	return ( c ? ((ts_cmo_params_t const *)c)->k : 0 );
 }
 
 int ts_cmo(
@@ -31,7 +31,7 @@ int ts_cmo(
 {
 	TS_PROLOGUE( ts_cmo_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_cmo_params_t *)c)->k;
+	uint_t k = ((ts_cmo_params_t const *)c)->k;
   if (k == 0 || n <= k) return -1;
 
 	for (uint_t j = 0; j < k; ++j) y[0][j] = 0;
diff --git a/lib/coppock_curve.c b/lib/coppock_curve.c
index dfa1ad2..e192bd1 100644
--- a/lib/coppock_curve.c
+++ b/lib/coppock_curve.c
@@ -33,9 +33,9 @@ int ts_coppock_curve(
     uint_t roc_short = 11;
     uint_t wma_period = 10;
 
-    if (n == 0 || n < roc_long) return -1;
+    if (n < roc_long) return -1;
 
-    fp_t *combined = calloc( n, sizeof( fp_t ) );
+ fp_t *combined = calloc( n, sizeof( fp_t ) );
     if ( !combined ) return -1;
 
     for ( uint_t i = roc_long; i < n; ++i )
@@ -50,7 +50,7 @@ int ts_coppock_curve(
         combined[i - roc_long] = roc14 + roc11;
     }
 
-    for (uint_t j = 0; j < n && j < roc_long; ++j) y[0][j] = 0;
+    for ( uint_t j = 0; j < n && j < roc_long; ++j ) y[0][j] = 0;
 
     for ( uint_t i = roc_long; i < n; ++i )
     {
diff --git a/lib/correlation_coefficient.c b/lib/correlation_coefficient.c
index d20d1ea..a806daf 100644
--- a/lib/correlation_coefficient.c
+++ b/lib/correlation_coefficient.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_correlation_coefficient_p = { .n_inputs = 2, .n_outputs
 uint_t ts_correlation_coefficient_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_correlation_coefficient_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_correlation_coefficient_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_correlation_coefficient(
@@ -31,7 +31,7 @@ int ts_correlation_coefficient(
 {
 	TS_PROLOGUE( ts_correlation_coefficient_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_correlation_coefficient_params_t *)c)->k;
+    uint_t k = ((ts_correlation_coefficient_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_y = 0, sum_xy = 0, sum_x2 = 0, sum_y2 = 0;
diff --git a/lib/cv.c b/lib/cv.c
index 0c06250..356716a 100644
--- a/lib/cv.c
+++ b/lib/cv.c
@@ -4,7 +4,7 @@
 //
 // EMA_fast(H-L) - EMA_slow(H-L), volatility measure
 //
-// Inputs:    5 (OHLCV)
+// Inputs:    4 (OHLC)
 // Outputs:   1 (CV)
 // Constants: 2 (fast, slow periods)
 
@@ -21,7 +21,7 @@ ts_parameter_t const ts_cv_p = { .n_inputs = 4, .n_outputs = 1, .n_constants = 2
 uint_t ts_cv_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? (uint_t)((ts_cv_params_t *)c)->slow : 0 );
+	return ( c ? (uint_t)((ts_cv_params_t const *)c)->slow : 0 );
 }
 
 int ts_cv(
@@ -32,9 +32,9 @@ int ts_cv(
 {
 	TS_PROLOGUE( ts_cv_p );
 	if ( !c ) return -1;
-	fp_t fast = ((ts_cv_params_t *)c)->fast;
-	fp_t slow = ((ts_cv_params_t *)c)->slow;
-	if (fast == 0 || slow == 0 || n == 0) return -1;
+	fp_t fast = ((ts_cv_params_t const *)c)->fast;
+	fp_t slow = ((ts_cv_params_t const *)c)->slow;
+	if (fast == 0 || slow == 0) return -1;
 
 	fp_t a_fast = 1.0 / fast;
 	fp_t a_slow = 1.0 / slow;
diff --git a/lib/darvas_box.c b/lib/darvas_box.c
index 573ed1e..a3bb5c1 100644
--- a/lib/darvas_box.c
+++ b/lib/darvas_box.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_darvas_box_p = { .n_inputs = 4, .n_outputs = 2, .n_const
 uint_t ts_darvas_box_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_darvas_box_params_t *)c)->k > 0 ? ((ts_darvas_box_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_darvas_box_params_t const *)c)->k > 0 ? ((ts_darvas_box_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_darvas_box(
@@ -32,7 +32,7 @@ int ts_darvas_box(
 {
 	TS_PROLOGUE( ts_darvas_box_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_darvas_box_params_t *)c)->k;
+	uint_t k = ((ts_darvas_box_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/decay_exponential.c b/lib/decay_exponential.c
index 97afe36..506d225 100644
--- a/lib/decay_exponential.c
+++ b/lib/decay_exponential.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_decay_exponential_p = { .n_inputs = 1, .n_outputs = 1, .
 uint_t ts_decay_exponential_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_decay_exponential_params_t *)c)->k : 0 );
+	return ( c ? ((ts_decay_exponential_params_t const *)c)->k : 0 );
 }
 
 int ts_decay_exponential(
@@ -34,8 +34,9 @@ int ts_decay_exponential(
 {
 	TS_PROLOGUE( ts_decay_exponential_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_decay_exponential_params_t *)c)->k;
-	if (k == 0 || n <= k) return -1;
+	uint_t k = ((ts_decay_exponential_params_t const *)c)->k;
+	if (k == 0) return -1;
+	if (n <= k) return -1;
 
 	fp_t a = ( fp_t ) 1.0 - _ts_reciprocal( k );
 
diff --git a/lib/decay_linear.c b/lib/decay_linear.c
index 8519d13..9d92b49 100644
--- a/lib/decay_linear.c
+++ b/lib/decay_linear.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_decay_linear_p = { .n_inputs = 1, .n_outputs = 1, .n_con
 uint_t ts_decay_linear_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_decay_linear_params_t *)c)->k : 0 );
+	return ( c ? ((ts_decay_linear_params_t const *)c)->k : 0 );
 }
 
 int ts_decay_linear(
@@ -36,47 +36,47 @@ int ts_decay_linear(
 {
 	TS_PROLOGUE( ts_decay_linear_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_decay_linear_params_t *)c)->k;
+	uint_t k = ((ts_decay_linear_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
-    for (uint_t zi = 0; zi < k; ++zi) y[0][zi] = 0;
+ for (uint_t zi = 0; zi < k; ++zi) y[0][zi] = 0;
 
-    uint_t xi = 1;
+	uint_t xi = 1;
 
-    fp_t prev = x[0][0];
-    fp_t r = prev / k;
+	fp_t prev = x[0][0];
+	fp_t r = prev / (fp_t)k;
 
 	for( ; xi < k; xi++ )
 	{
-	    prev -= r;
+		prev -= r;
 
-	    if( x[0][xi] > prev )
-	    {
-	        prev = x[0][xi];
-	        r = x[0][xi] / k;
-	    }
-	    else
-	    {
-            prev = fmax( prev, 0 );
-        }
+		if( x[0][xi] > prev )
+		{
+			prev = x[0][xi];
+			r = x[0][xi] / (fp_t)k;
+		}
+		else
+		{
+			prev = fmax( prev, 0 );
+		}
 	}
 
 	for( uint_t yi = k; xi < n; xi++, yi++ )
 	{
-	    fp_t curr = prev - r;
+		fp_t curr = prev - r;
 
-	    if( x[0][xi] > curr )
-	    {
-	        curr = x[0][xi];
-	        r = x[0][xi] / k;
-	    }
-	    else
-	    {
-            curr = fmax( curr, 0 );
-        }
+		if( x[0][xi] > curr )
+		{
+			curr = x[0][xi];
+			r = x[0][xi] / (fp_t)k;
+		}
+		else
+		{
+			curr = fmax( curr, 0 );
+		}
 
-        y[0][yi] = curr;
-        prev = curr;
+		y[0][yi] = curr;
+		prev = curr;
 	}
 	return 0;
 }
diff --git a/lib/delta.c b/lib/delta.c
index 02ccb66..2ee037a 100644
--- a/lib/delta.c
+++ b/lib/delta.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_delta_p = { .n_inputs = 1, .n_outputs = 1, .n_constants
 uint_t ts_delta_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_delta_params_t *)c)->k : 0 );
+	return ( c ? ((ts_delta_params_t const *)c)->k : 0 );
 }
 
 int ts_delta(
@@ -35,7 +35,7 @@ int ts_delta(
 {
 	TS_PROLOGUE( ts_delta_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_delta_params_t *)c)->k;
+	uint_t k = ((ts_delta_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = k;
diff --git a/lib/deviation_average.c b/lib/deviation_average.c
index 5ac7109..552d226 100644
--- a/lib/deviation_average.c
+++ b/lib/deviation_average.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_deviation_average_p = { .n_inputs = 1, .n_outputs = 1, .
 uint_t ts_deviation_average_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_deviation_average_params_t *)c)->k > 0 ? ((ts_deviation_average_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_deviation_average_params_t const *)c)->k > 0 ? ((ts_deviation_average_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_deviation_average(
@@ -32,7 +32,7 @@ int ts_deviation_average(
 {
 	TS_PROLOGUE( ts_deviation_average_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_deviation_average_params_t *)c)->k;
+	uint_t k = ((ts_deviation_average_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/deviation_standard.c b/lib/deviation_standard.c
index a2a0a76..f843224 100644
--- a/lib/deviation_standard.c
+++ b/lib/deviation_standard.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_deviation_standard_p = { .n_inputs = 1, .n_outputs = 1,
 uint_t ts_deviation_standard_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_deviation_standard_params_t *)c)->k > 0 ? ((ts_deviation_standard_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_deviation_standard_params_t const *)c)->k > 0 ? ((ts_deviation_standard_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_deviation_standard(
@@ -32,7 +32,7 @@ int ts_deviation_standard(
 	TS_PROLOGUE( ts_deviation_standard_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_deviation_standard_params_t *)c)->k;
+	uint_t k = ((ts_deviation_standard_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/deviation_standard_average_exponential.c b/lib/deviation_standard_average_exponential.c
index 8c484f5..a27cc6a 100644
--- a/lib/deviation_standard_average_exponential.c
+++ b/lib/deviation_standard_average_exponential.c
@@ -32,9 +32,8 @@ int ts_deviation_standard_average_exponential(
 {
 	TS_PROLOGUE( ts_deviation_standard_average_exponential_p );
 	if ( !c ) return -1;
-	if (n == 0) return -1;
 
-	fp_t a = ((ts_deviation_standard_average_exponential_params_t *)c)->a;
+	fp_t a = ((ts_deviation_standard_average_exponential_params_t const *)c)->a;
 	if (a == 0) return -1;
 
 	y[0][0] = x[0][0];
diff --git a/lib/deviation_vector.c b/lib/deviation_vector.c
index 4f10037..02d9f72 100644
--- a/lib/deviation_vector.c
+++ b/lib/deviation_vector.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_deviation_vector_p = { .n_inputs = 1, .n_outputs = 1, .n
 uint_t ts_deviation_vector_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_deviation_vector_params_t *)c)->k > 0 ? ((ts_deviation_vector_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_deviation_vector_params_t const *)c)->k > 0 ? ((ts_deviation_vector_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_deviation_vector(
@@ -31,7 +31,7 @@ int ts_deviation_vector(
 {
 	TS_PROLOGUE( ts_deviation_vector_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_deviation_vector_params_t *)c)->k;
+    uint_t k = ((ts_deviation_vector_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for (uint_t i = 0; i < n; ++i)
diff --git a/lib/di_minus.c b/lib/di_minus.c
index 95b0559..7fe0115 100644
--- a/lib/di_minus.c
+++ b/lib/di_minus.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_di_minus_p = { .n_inputs = 4, .n_outputs = 1, .n_constan
 uint_t ts_di_minus_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_di_minus_params_t *)c)->k : 0 );
+	return ( c ? ((ts_di_minus_params_t const *)c)->k : 0 );
 }
 
 int ts_di_minus(
@@ -32,7 +32,7 @@ int ts_di_minus(
 {
 	TS_PROLOGUE( ts_di_minus_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_di_minus_params_t *)c)->k;
+	uint_t k = ((ts_di_minus_params_t const *)c)->k;
 	if (k == 0 || n < 2) return -1;
 	fp_t *ema_minus = calloc( n, sizeof( fp_t ) );
 	fp_t *ema_plus = calloc( n, sizeof( fp_t ) );
diff --git a/lib/di_plus.c b/lib/di_plus.c
index fb3c076..2939fc5 100644
--- a/lib/di_plus.c
+++ b/lib/di_plus.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_di_plus_p = { .n_inputs = 4, .n_outputs = 1, .n_constant
 uint_t ts_di_plus_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_di_plus_params_t *)c)->k : 0 );
+	return ( c ? ((ts_di_plus_params_t const *)c)->k : 0 );
 }
 
 int ts_di_plus(
@@ -32,7 +32,7 @@ int ts_di_plus(
 {
 	TS_PROLOGUE( ts_di_plus_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_di_plus_params_t *)c)->k;
+	uint_t k = ((ts_di_plus_params_t const *)c)->k;
 	if (k == 0 || n < 2) return -1;
 	fp_t *ema_plus = calloc( n, sizeof( fp_t ) );
 	fp_t *ema_minus = calloc( n, sizeof( fp_t ) );
diff --git a/lib/disparity_index.c b/lib/disparity_index.c
index ebf5e0d..2909033 100644
--- a/lib/disparity_index.c
+++ b/lib/disparity_index.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_disparity_index_p = { .n_inputs = 1, .n_outputs = 1, .n_
 uint_t ts_disparity_index_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_disparity_index_params_t *)c)->k > 0 ? ((ts_disparity_index_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_disparity_index_params_t const *)c)->k > 0 ? ((ts_disparity_index_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_disparity_index(
@@ -31,7 +31,7 @@ int ts_disparity_index(
 {
 	TS_PROLOGUE( ts_disparity_index_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_disparity_index_params_t *)c)->k;
+    uint_t k = ((ts_disparity_index_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum = 0;
diff --git a/lib/donchian_channel.c b/lib/donchian_channel.c
index 760c396..93ae589 100644
--- a/lib/donchian_channel.c
+++ b/lib/donchian_channel.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_donchian_channel_p = { .n_inputs = 4, .n_outputs = 3, .n
 uint_t ts_donchian_channel_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_donchian_channel_params_t *)c)->k > 0 ? ((ts_donchian_channel_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_donchian_channel_params_t const *)c)->k > 0 ? ((ts_donchian_channel_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_donchian_channel(
@@ -33,7 +33,7 @@ int ts_donchian_channel(
 {
 	TS_PROLOGUE( ts_donchian_channel_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_donchian_channel_params_t *)c)->k;
+    uint_t k = ((ts_donchian_channel_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for ( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/donchian_width.c b/lib/donchian_width.c
index c69936f..f6eb42c 100644
--- a/lib/donchian_width.c
+++ b/lib/donchian_width.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_donchian_width_p = { .n_inputs = 4, .n_outputs = 1, .n_c
 uint_t ts_donchian_width_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_donchian_width_params_t *)c)->k > 0 ? ((ts_donchian_width_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_donchian_width_params_t const *)c)->k > 0 ? ((ts_donchian_width_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_donchian_width(
@@ -31,7 +31,7 @@ int ts_donchian_width(
 {
 	TS_PROLOGUE( ts_donchian_width_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_donchian_width_params_t *)c)->k;
+    uint_t k = ((ts_donchian_width_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for ( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/dpo.c b/lib/dpo.c
index 5bf069b..5d481a7 100644
--- a/lib/dpo.c
+++ b/lib/dpo.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_dpo_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_dpo_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_dpo_params_t *)c)->k / 2 + 1 : 0 );
+	return ( c ? ((ts_dpo_params_t const *)c)->k / 2 + 1 : 0 );
 }
 
 int ts_dpo(
@@ -32,7 +32,7 @@ int ts_dpo(
 {
 	TS_PROLOGUE( ts_dpo_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_dpo_params_t *)c)->k;
+    uint_t k = ((ts_dpo_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     uint_t sma_period = k;
diff --git a/lib/dx.c b/lib/dx.c
index b4552fa..8ae355f 100644
--- a/lib/dx.c
+++ b/lib/dx.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_dx_p = { .n_inputs = 4, .n_outputs = 1, .n_constants = 1
 uint_t ts_dx_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_dx_params_t *)c)->k : 0 );
+	return ( c ? ((ts_dx_params_t const *)c)->k : 0 );
 }
 
 int ts_dx(
@@ -32,7 +32,7 @@ int ts_dx(
 {
 	TS_PROLOGUE( ts_dx_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_dx_params_t *)c)->k;
+	uint_t k = ((ts_dx_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	fp_t *plus_dm_arr = calloc( n, sizeof( fp_t ) );
diff --git a/lib/ease_of_movement.c b/lib/ease_of_movement.c
index d16f32c..f6f1f46 100644
--- a/lib/ease_of_movement.c
+++ b/lib/ease_of_movement.c
@@ -31,7 +31,7 @@ int ts_ease_of_movement(
 {
 	TS_PROLOGUE( ts_ease_of_movement_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_ease_of_movement_params_t *)c)->k;
+    uint_t k = ((ts_ease_of_movement_params_t const *)c)->k;
     if (k == 0 || n <= k) return -1;
 
     fp_t *eom = calloc( n, sizeof( fp_t ) );
diff --git a/lib/elder_force_index.c b/lib/elder_force_index.c
index 23cce66..c2b367c 100644
--- a/lib/elder_force_index.c
+++ b/lib/elder_force_index.c
@@ -31,7 +31,7 @@ int ts_elder_force_index(
 {
 	TS_PROLOGUE( ts_elder_force_index_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_elder_force_index_params_t *)c)->k;
+    uint_t k = ((ts_elder_force_index_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
     fp_t a = 1.0 / k;
 
diff --git a/lib/elder_impulse.c b/lib/elder_impulse.c
index d629e7c..b86514d 100644
--- a/lib/elder_impulse.c
+++ b/lib/elder_impulse.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_elder_impulse_p = { .n_inputs = 1, .n_outputs = 2, .n_co
 uint_t ts_elder_impulse_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? 2 * ((ts_elder_impulse_params_t *)c)->k - 1 : 0 );
+	return ( c ? 2 * ((ts_elder_impulse_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_elder_impulse(
@@ -31,7 +31,7 @@ int ts_elder_impulse(
 {
 	TS_PROLOGUE( ts_elder_impulse_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_elder_impulse_params_t *)c)->k;
+    uint_t k = ((ts_elder_impulse_params_t const *)c)->k;
     if (k == 0 || n < 2 * k - 1) return -1;
 
     fp_t *sma = malloc( n * sizeof( fp_t ) );
diff --git a/lib/elder_ray.c b/lib/elder_ray.c
index a0f330f..730810b 100644
--- a/lib/elder_ray.c
+++ b/lib/elder_ray.c
@@ -33,7 +33,7 @@ int ts_elder_ray(
 {
 	TS_PROLOGUE( ts_elder_ray_p );
 	if ( !c ) return -1;
-	fp_t k = ((ts_elder_ray_params_t *)c)->k;
+	fp_t k = ((ts_elder_ray_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 	fp_t a = 1.0 / k;
 	fp_t *ema = calloc( n, sizeof( fp_t ) );
diff --git a/lib/ema_variable.c b/lib/ema_variable.c
index c20fee2..38f505e 100644
--- a/lib/ema_variable.c
+++ b/lib/ema_variable.c
@@ -31,9 +31,8 @@ int ts_ema_variable(
 {
 	TS_PROLOGUE( ts_ema_variable_p );
 	if ( !c ) return -1;
-    fp_t k = ((ts_ema_variable_params_t *)c)->k;
+    fp_t k = ((ts_ema_variable_params_t const *)c)->k;
     if (k <= 0) return -1;
-    if (n == 0) return -1;
 
     fp_t alpha = 2.0 / (k + 1.0);
     y[0][0] = x[0][0];
diff --git a/lib/envelope.c b/lib/envelope.c
index 1ddda0c..0813ee5 100644
--- a/lib/envelope.c
+++ b/lib/envelope.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_envelope_p = { .n_inputs = 1, .n_outputs = 2, .n_constan
 uint_t ts_envelope_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_envelope_params_t *)c)->k > 0 ? ((ts_envelope_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_envelope_params_t const *)c)->k > 0 ? ((ts_envelope_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_envelope(
@@ -32,8 +32,8 @@ int ts_envelope(
 {
 	TS_PROLOGUE( ts_envelope_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_envelope_params_t *)c)->k;
-    fp_t pct = ((ts_envelope_params_t *)c)->pct;
+    uint_t k = ((ts_envelope_params_t const *)c)->k;
+    fp_t pct = ((ts_envelope_params_t const *)c)->pct;
     if (k == 0 || n < k) return -1;
 
     fp_t sum = 0;
diff --git a/lib/exponential.c b/lib/exponential.c
index b3a6205..a4e19c9 100644
--- a/lib/exponential.c
+++ b/lib/exponential.c
@@ -36,7 +36,7 @@ int ts_exponential(
 {
 	TS_PROLOGUE( ts_exponential_p );
 	if ( !c ) return -1;
-	fp_t b = ((ts_exponential_params_t *)c)->b;
+	fp_t b = ((ts_exponential_params_t const *)c)->b;
 	if (b <= 0) return -1;
 
 	for( uint_t i = 0; i < n; ++i )
diff --git a/lib/factorial.c b/lib/factorial.c
index 8e64fa3..7e82ffb 100644
--- a/lib/factorial.c
+++ b/lib/factorial.c
@@ -8,6 +8,7 @@
 // Outputs:   1 (n!)
 // Constants: 0
 
+#include <math.h>
 #include "ts.h"
 
 
@@ -31,7 +32,7 @@ int ts_factorial(
 	(void)c;
 	for( uint_t i = 0; i < n; ++i )
 	{
-		if (x[0][i] < 0) { y[0][i] = NAN; continue; }
+		if (isnan(x[0][i]) || isinf(x[0][i]) || x[0][i] < 0) { y[0][i] = NAN; continue; }
 		fp_t result = 1.0;
 		uint_t k = (uint_t)x[0][i];
 		if (k > 170) k = 170;
diff --git a/lib/fill_indicator.c b/lib/fill_indicator.c
index 9cb9cbc..448c32d 100644
--- a/lib/fill_indicator.c
+++ b/lib/fill_indicator.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_fill_indicator_p = { .n_inputs = 4, .n_outputs = 1, .n_c
 uint_t ts_fill_indicator_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_fill_indicator_params_t *)c)->k > 0 ? ((ts_fill_indicator_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_fill_indicator_params_t const *)c)->k > 0 ? ((ts_fill_indicator_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_fill_indicator(
@@ -31,7 +31,7 @@ int ts_fill_indicator(
 {
 	TS_PROLOGUE( ts_fill_indicator_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_fill_indicator_params_t *)c)->k;
+	uint_t k = ((ts_fill_indicator_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/fisher_transform.c b/lib/fisher_transform.c
index 2b416ba..1bf8c51 100644
--- a/lib/fisher_transform.c
+++ b/lib/fisher_transform.c
@@ -20,7 +20,7 @@ ts_parameter_t const ts_fisher_transform_p = { .n_inputs = 4, .n_outputs = 2, .n
 uint_t ts_fisher_transform_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_fisher_transform_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_fisher_transform_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_fisher_transform(
@@ -31,7 +31,7 @@ int ts_fisher_transform(
 {
 	TS_PROLOGUE( ts_fisher_transform_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_fisher_transform_params_t *)c)->k;
+    uint_t k = ((ts_fisher_transform_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for (uint_t i = k - 1; i < n; ++i)
diff --git a/lib/fractal_chaos_bands.c b/lib/fractal_chaos_bands.c
index 57bbf00..1cbef90 100644
--- a/lib/fractal_chaos_bands.c
+++ b/lib/fractal_chaos_bands.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_fractal_chaos_bands_p = { .n_inputs = 4, .n_outputs = 2,
 uint_t ts_fractal_chaos_bands_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_fractal_chaos_bands_params_t *)c)->k / 2 : 0 );
+	return ( c ? ((ts_fractal_chaos_bands_params_t const *)c)->k / 2 : 0 );
 }
 
 int ts_fractal_chaos_bands(
@@ -33,7 +33,8 @@ int ts_fractal_chaos_bands(
 {
 	TS_PROLOGUE( ts_fractal_chaos_bands_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_fractal_chaos_bands_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+    uint_t k = ((ts_fractal_chaos_bands_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t alpha = 2.0 / (k + 1.0);
@@ -69,6 +70,13 @@ int ts_fractal_chaos_bands(
         y[0][i] = ema_upper;
         y[1][i] = ema_lower;
     }
+
+    for ( uint_t i = n - half_k; i < n; ++i )
+    {
+        y[0][i] = 0;
+        y[1][i] = 0;
+    }
+
 	return 0;
 }
 
diff --git a/lib/fractal_chaos_oscillator.c b/lib/fractal_chaos_oscillator.c
index 5c845d3..835bb05 100644
--- a/lib/fractal_chaos_oscillator.c
+++ b/lib/fractal_chaos_oscillator.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_fractal_chaos_oscillator_p = { .n_inputs = 4, .n_outputs
 uint_t ts_fractal_chaos_oscillator_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_fractal_chaos_oscillator_params_t *)c)->k / 2 : 0 );
+	return ( c ? ((ts_fractal_chaos_oscillator_params_t const *)c)->k / 2 : 0 );
 }
 
 int ts_fractal_chaos_oscillator(
@@ -33,7 +33,7 @@ int ts_fractal_chaos_oscillator(
 {
 	TS_PROLOGUE( ts_fractal_chaos_oscillator_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_fractal_chaos_oscillator_params_t *)c)->k;
+    uint_t k = ((ts_fractal_chaos_oscillator_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t alpha = 2.0 / (k + 1.0);
diff --git a/lib/gamma_pdf.c b/lib/gamma_pdf.c
index 977f8b7..7a8370c 100644
--- a/lib/gamma_pdf.c
+++ b/lib/gamma_pdf.c
@@ -34,7 +34,7 @@ int ts_gamma_pdf(
 {
 	TS_PROLOGUE( ts_gamma_pdf_p );
 	if ( !c ) return -1;
-	fp_t shape = ((ts_gamma_pdf_params_t *)c)->shape;
+	fp_t shape = ((ts_gamma_pdf_params_t const *)c)->shape;
 	if (shape <= 0.0) return -1;
 
 	for( uint_t i = 0; i < n; ++i )
diff --git a/lib/gcd.c b/lib/gcd.c
index 44068cf..8ca3861 100644
--- a/lib/gcd.c
+++ b/lib/gcd.c
@@ -31,18 +31,25 @@ int ts_gcd(
 {
 	TS_PROLOGUE( ts_gcd_p );
 	(void)c;
-    for( uint_t i = 0; i < n; ++i )
-    {
-        long a = (long)fabs(x[0][i]);
-        long b = (long)fabs(x[1][i]);
-        while( b )
-        {
-            long t = b;
-            b = a % b;
-            a = t;
-        }
-        y[0][i] = (fp_t)a;
-    }
+ for( uint_t i = 0; i < n; ++i )
+	{
+		fp_t ax = fabs(x[0][i]);
+		fp_t bx = fabs(x[1][i]);
+		if (ax > 9223372036854775807.0 || bx > 9223372036854775807.0)
+		{
+			y[0][i] = 0;
+			continue;
+		}
+		long a = (long)ax;
+		long b = (long)bx;
+		while( b )
+		{
+			long t = b;
+			b = a % b;
+			a = t;
+		}
+		y[0][i] = (fp_t)fabs((fp_t)a);
+	}
 	return 0;
 }
 
diff --git a/lib/gopalakrishnan_range_index.c b/lib/gopalakrishnan_range_index.c
index 80da0b4..17e3d66 100644
--- a/lib/gopalakrishnan_range_index.c
+++ b/lib/gopalakrishnan_range_index.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_gopalakrishnan_range_index_p = { .n_inputs = 4, .n_outpu
 uint_t ts_gopalakrishnan_range_index_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_gopalakrishnan_range_index_params_t *)c)->k : 0 );
+	return ( c ? ((ts_gopalakrishnan_range_index_params_t const *)c)->k : 0 );
 }
 
 int ts_gopalakrishnan_range_index(
@@ -34,7 +34,7 @@ int ts_gopalakrishnan_range_index(
 {
 	TS_PROLOGUE( ts_gopalakrishnan_range_index_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_gopalakrishnan_range_index_params_t *)c)->k;
+	uint_t k = ((ts_gopalakrishnan_range_index_params_t const *)c)->k;
   if (k == 0 || n <= k) return -1;
 
 	fp_t sum_abs = 0;
diff --git a/lib/harmonic.c b/lib/harmonic.c
index 2c69ee8..c9920c9 100644
--- a/lib/harmonic.c
+++ b/lib/harmonic.c
@@ -1,10 +1,10 @@
-// Harmonic
+// Harmonic Number
 //
 // harmonic
 //
-// Harmonic mean
+// Harmonic number H(n) = Σ(1/k) for k=1..n
 //
-// H = n / Σ(1/x_i)
+// H(n) = 1 + 1/2 + 1/3 + ... + 1/n
 //
 // Inputs:    1
 // Outputs:   1
diff --git a/lib/high_low_bands.c b/lib/high_low_bands.c
index 544796f..cc05feb 100644
--- a/lib/high_low_bands.c
+++ b/lib/high_low_bands.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_high_low_bands_p = { .n_inputs = 4, .n_outputs = 2, .n_c
 uint_t ts_high_low_bands_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? 2 * ((ts_high_low_bands_params_t *)c)->k - 2 : 0 );
+	return ( c ? 2 * ((ts_high_low_bands_params_t const *)c)->k - 2 : 0 );
 }
 
 int ts_high_low_bands(
@@ -34,7 +34,7 @@ int ts_high_low_bands(
 {
 	TS_PROLOGUE( ts_high_low_bands_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_high_low_bands_params_t *)c)->k;
+	uint_t k = ((ts_high_low_bands_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = 2 * k - 2; i < n; ++i )
diff --git a/lib/highest_high.c b/lib/highest_high.c
index d3ac753..22bd845 100644
--- a/lib/highest_high.c
+++ b/lib/highest_high.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_highest_high_p = { .n_inputs = 4, .n_outputs = 1, .n_con
 uint_t ts_highest_high_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_highest_high_params_t *)c)->k > 0 ? ((ts_highest_high_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_highest_high_params_t const *)c)->k > 0 ? ((ts_highest_high_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_highest_high(
@@ -34,7 +34,7 @@ int ts_highest_high(
 {
 	TS_PROLOGUE( ts_highest_high_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_highest_high_params_t *)c)->k;
+	uint_t k = ((ts_highest_high_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	fp_t max_val = ts_h( x, 0 );
diff --git a/lib/historical_volatility.c b/lib/historical_volatility.c
index cde0d91..5848d1c 100644
--- a/lib/historical_volatility.c
+++ b/lib/historical_volatility.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_historical_volatility_p = { .n_inputs = 1, .n_outputs =
 uint_t ts_historical_volatility_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_historical_volatility_params_t *)c)->k > 0 ? ((ts_historical_volatility_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_historical_volatility_params_t const *)c)->k > 0 ? ((ts_historical_volatility_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_historical_volatility(
@@ -34,7 +34,7 @@ int ts_historical_volatility(
 {
 	TS_PROLOGUE( ts_historical_volatility_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_historical_volatility_params_t *)c)->k;
+    uint_t k = ((ts_historical_volatility_params_t const *)c)->k;
     if (k == 0 || n < k + 1) return -1;
 
     for ( uint_t d = k - 1; d < n - 1; ++d )
diff --git a/lib/hull_ma.c b/lib/hull_ma.c
index e412a6f..1870397 100644
--- a/lib/hull_ma.c
+++ b/lib/hull_ma.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_hull_ma_p = { .n_inputs = 1, .n_outputs = 1, .n_constant
 uint_t ts_hull_ma_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_hull_ma_params_t *)c)->k + (uint_t)sqrt((fp_t)((ts_hull_ma_params_t *)c)->k) - 2 : 0 );
+	return ( c ? ((ts_hull_ma_params_t const *)c)->k + (uint_t)sqrt((fp_t)((ts_hull_ma_params_t const *)c)->k) - 2 : 0 );
 }
 
 int ts_hull_ma(
@@ -36,7 +36,7 @@ int ts_hull_ma(
 	TS_PROLOGUE( ts_hull_ma_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-    uint_t k = ((ts_hull_ma_params_t *)c)->k;
+    uint_t k = ((ts_hull_ma_params_t const *)c)->k;
     if (k < 2) return -1;
 
     uint_t half_k = k / 2;
diff --git a/lib/hurst_exponent.c b/lib/hurst_exponent.c
index aa58036..3eea141 100644
--- a/lib/hurst_exponent.c
+++ b/lib/hurst_exponent.c
@@ -34,7 +34,7 @@ int ts_hurst_exponent(
 {
 	TS_PROLOGUE( ts_hurst_exponent_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_hurst_exponent_params_t *)c)->k;
+    uint_t k = ((ts_hurst_exponent_params_t const *)c)->k;
     if (k == 0 || k > n) return -1;
 
     for ( uint_t i = 0; i < n; ++i )
diff --git a/lib/ichimoku.c b/lib/ichimoku.c
index 76f85e6..da63626 100644
--- a/lib/ichimoku.c
+++ b/lib/ichimoku.c
@@ -42,7 +42,7 @@ int ts_ichimoku(
 
 	if ( c )
 	{
-		ts_ichimoku_params_t *p = (ts_ichimoku_params_t *)c;
+		ts_ichimoku_params_t const *p = (ts_ichimoku_params_t const *)c;
 		if ( p->tenkan > 0 ) tenkan = p->tenkan;
 		if ( p->kijun > 0 ) kijun = p->kijun;
 		if ( p->senkou > 0 ) senkou = p->senkou;
diff --git a/lib/kalman_filter.c b/lib/kalman_filter.c
index f7adf6f..a5ac5bf 100644
--- a/lib/kalman_filter.c
+++ b/lib/kalman_filter.c
@@ -36,12 +36,11 @@ int ts_kalman_filter(
 	TS_PROLOGUE( ts_kalman_filter_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-    fp_t Q = ((ts_kalman_filter_params_t *)c)->Q;
-    fp_t R = ((ts_kalman_filter_params_t *)c)->R;
+    fp_t Q = ((ts_kalman_filter_params_t const *)c)->Q;
+    fp_t R = ((ts_kalman_filter_params_t const *)c)->R;
 
     if (Q < 0 || R < 0) return -1;
     if (isnan(Q) || isnan(R)) return -1;
-    if (n == 0) return -1;
     fp_t x_est = x[0][0];
     /* NOTE: P=1.0 is a reasonable default for normalized data.
      * For price data in the range of 100-3000, consider initializing
diff --git a/lib/kaufman_adaptive_ma.c b/lib/kaufman_adaptive_ma.c
index f56c6a1..8822344 100644
--- a/lib/kaufman_adaptive_ma.c
+++ b/lib/kaufman_adaptive_ma.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_kaufman_adaptive_ma_p = { .n_inputs = 1, .n_outputs = 1,
 uint_t ts_kaufman_adaptive_ma_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_kaufman_adaptive_ma_params_t *)c)->k : 0 );
+	return ( c ? ((ts_kaufman_adaptive_ma_params_t const *)c)->k : 0 );
 }
 
 int ts_kaufman_adaptive_ma(
@@ -34,7 +34,7 @@ int ts_kaufman_adaptive_ma(
 {
 	TS_PROLOGUE( ts_kaufman_adaptive_ma_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_kaufman_adaptive_ma_params_t *)c)->k;
+    uint_t k = ((ts_kaufman_adaptive_ma_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t ama = x[0][0];
diff --git a/lib/keltner_channel.c b/lib/keltner_channel.c
index 259be03..c4bf3f6 100644
--- a/lib/keltner_channel.c
+++ b/lib/keltner_channel.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_keltner_channel_p = { .n_inputs = 4, .n_outputs = 3, .n_
 uint_t ts_keltner_channel_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_keltner_channel_params_t *)c)->k : 0 );
+	return ( c ? ((ts_keltner_channel_params_t const *)c)->k : 0 );
 }
 
 int ts_keltner_channel(
@@ -34,7 +34,7 @@ int ts_keltner_channel(
 {
 	TS_PROLOGUE( ts_keltner_channel_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_keltner_channel_params_t *)c)->k;
+    uint_t k = ((ts_keltner_channel_params_t const *)c)->k;
     if (k == 0 || n <= k) return -1;
 
     fp_t a = 2.0 / ((fp_t)k + 1.0);
diff --git a/lib/kvo.c b/lib/kvo.c
index 229fad8..1e2a15b 100644
--- a/lib/kvo.c
+++ b/lib/kvo.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_kvo_p = { .n_inputs = 5, .n_outputs = 2, .n_constants =
 uint_t ts_kvo_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_kvo_params_t *)c)->k1 > 10 ? ((ts_kvo_params_t *)c)->k1 : 10 : 0 );
+	return ( c ? ((ts_kvo_params_t const *)c)->k1 > 10 ? ((ts_kvo_params_t const *)c)->k1 : 10 : 0 );
 }
 
 int ts_kvo(
@@ -35,8 +35,8 @@ int ts_kvo(
 {
 	TS_PROLOGUE( ts_kvo_p );
 	if ( !c ) return -1;
-    uint_t k1 = ((ts_kvo_params_t *)c)->k1;
-    fp_t f0_raw = ((ts_kvo_params_t *)c)->f0;
+    uint_t k1 = ((ts_kvo_params_t const *)c)->k1;
+    fp_t f0_raw = ((ts_kvo_params_t const *)c)->f0;
     if (isnan(f0_raw) || isinf(f0_raw) || f0_raw < 0) return -1;
     uint_t k10 = (uint_t)f0_raw;
     if (k1 == 0) return -1;
diff --git a/lib/lag.c b/lib/lag.c
index 1e3f657..22d1146 100644
--- a/lib/lag.c
+++ b/lib/lag.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_lag_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_lag_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_lag_params_t *)c)->k : 0 );
+	return ( c ? ((ts_lag_params_t const *)c)->k : 0 );
 }
 
 int ts_lag(
@@ -35,10 +35,10 @@ int ts_lag(
 {
 	TS_PROLOGUE( ts_lag_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_lag_params_t *)c)->k;
+	uint_t k = ((ts_lag_params_t const *)c)->k;
 	if (k == 0) return -1;
 
-	fp_t insert = ((ts_lag_params_t *)c)->insert;
+	fp_t insert = ((ts_lag_params_t const *)c)->insert;
 
 	if (n <= k) return -1;
 
diff --git a/lib/lcm.c b/lib/lcm.c
index c8b52ef..8fbbce5 100644
--- a/lib/lcm.c
+++ b/lib/lcm.c
@@ -31,30 +31,34 @@ int ts_lcm(
 {
 	TS_PROLOGUE( ts_lcm_p );
 	(void)c;
-    for( uint_t i = 0; i < n; ++i )
-    {
-        fp_t ax = fabs(x[0][i]);
-        fp_t bx = fabs(x[1][i]);
-        if (ax > 1e15 || bx > 1e15) { y[0][i] = 0.0; continue; }
-        long a = (long)ax;
-        long b = (long)bx;
-        if( !a || !b )
-        {
-            y[0][i] = 0.0;
-        }
-        else
-        {
-            long ta = a;
-            long tb = b;
-            while( tb )
-            {
-                long t = tb;
-                tb = ta % tb;
-                ta = t;
-            }
-            y[0][i] = (fp_t)(a / ta) * (fp_t)b;
-        }
-    }
+ for( uint_t i = 0; i < n; ++i )
+	{
+		fp_t ax = fabs(x[0][i]);
+		fp_t bx = fabs(x[1][i]);
+		if (ax > 9223372036854775807.0 || bx > 9223372036854775807.0)
+		{
+			y[0][i] = 0.0;
+			continue;
+		}
+		long a = (long)ax;
+		long b = (long)bx;
+		if( !a || !b )
+		{
+			y[0][i] = 0.0;
+		}
+		else
+		{
+			long ta = a;
+			long tb = b;
+			while( tb )
+			{
+				long t = tb;
+				tb = ta % tb;
+				ta = t;
+			}
+			y[0][i] = (fp_t)(a / ta) * (fp_t)b;
+		}
+	}
 	return 0;
 }
 
diff --git a/lib/linear_regression.c b/lib/linear_regression.c
index 5d595bc..842df1f 100644
--- a/lib/linear_regression.c
+++ b/lib/linear_regression.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_linear_regression_p = { .n_inputs = 1, .n_outputs = 1, .
 uint_t ts_linear_regression_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_linear_regression_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_linear_regression_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_linear_regression(
@@ -35,7 +35,7 @@ int ts_linear_regression(
 	TS_PROLOGUE( ts_linear_regression_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-    uint_t k = ((ts_linear_regression_params_t *)c)->k;
+    uint_t k = ((ts_linear_regression_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     // Precompute constant x sums (x values are always 0..k-1)
diff --git a/lib/linear_regression_angle.c b/lib/linear_regression_angle.c
index 22928bc..0f60024 100644
--- a/lib/linear_regression_angle.c
+++ b/lib/linear_regression_angle.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_linear_regression_angle_p = { .n_inputs = 1, .n_outputs
 uint_t ts_linear_regression_angle_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_linear_regression_angle_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_linear_regression_angle_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_linear_regression_angle(
@@ -34,7 +34,7 @@ int ts_linear_regression_angle(
 {
 	TS_PROLOGUE( ts_linear_regression_angle_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_linear_regression_angle_params_t *)c)->k;
+    uint_t k = ((ts_linear_regression_angle_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_x2 = 0;
diff --git a/lib/linear_regression_forecast.c b/lib/linear_regression_forecast.c
index 02a78a8..73f974c 100644
--- a/lib/linear_regression_forecast.c
+++ b/lib/linear_regression_forecast.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_linear_regression_forecast_p = { .n_inputs = 1, .n_outpu
 uint_t ts_linear_regression_forecast_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_linear_regression_forecast_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_linear_regression_forecast_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_linear_regression_forecast(
@@ -34,7 +34,7 @@ int ts_linear_regression_forecast(
 {
 	TS_PROLOGUE( ts_linear_regression_forecast_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_linear_regression_forecast_params_t *)c)->k;
+    uint_t k = ((ts_linear_regression_forecast_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_x2 = 0;
diff --git a/lib/linear_regression_intercept.c b/lib/linear_regression_intercept.c
index 2b26478..adb153c 100644
--- a/lib/linear_regression_intercept.c
+++ b/lib/linear_regression_intercept.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_linear_regression_intercept_p = { .n_inputs = 1, .n_outp
 uint_t ts_linear_regression_intercept_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_linear_regression_intercept_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_linear_regression_intercept_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_linear_regression_intercept(
@@ -33,7 +33,7 @@ int ts_linear_regression_intercept(
 {
 	TS_PROLOGUE( ts_linear_regression_intercept_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_linear_regression_intercept_params_t *)c)->k;
+    uint_t k = ((ts_linear_regression_intercept_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_x2 = 0;
diff --git a/lib/linear_regression_r2.c b/lib/linear_regression_r2.c
index 5cec662..c15ee67 100644
--- a/lib/linear_regression_r2.c
+++ b/lib/linear_regression_r2.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_linear_regression_r2_p = { .n_inputs = 1, .n_outputs = 1
 uint_t ts_linear_regression_r2_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_linear_regression_r2_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_linear_regression_r2_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_linear_regression_r2(
@@ -34,7 +34,7 @@ int ts_linear_regression_r2(
 {
 	TS_PROLOGUE( ts_linear_regression_r2_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_linear_regression_r2_params_t *)c)->k;
+    uint_t k = ((ts_linear_regression_r2_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_x2 = 0;
diff --git a/lib/linear_regression_slope.c b/lib/linear_regression_slope.c
index d20ca8e..5bdc01f 100644
--- a/lib/linear_regression_slope.c
+++ b/lib/linear_regression_slope.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_linear_regression_slope_p = { .n_inputs = 1, .n_outputs
 uint_t ts_linear_regression_slope_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_linear_regression_slope_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_linear_regression_slope_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_linear_regression_slope(
@@ -33,7 +33,7 @@ int ts_linear_regression_slope(
 {
 	TS_PROLOGUE( ts_linear_regression_slope_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_linear_regression_slope_params_t *)c)->k;
+    uint_t k = ((ts_linear_regression_slope_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_x2 = 0;
diff --git a/lib/linear_weighted_ma.c b/lib/linear_weighted_ma.c
index 70f660e..e11bf54 100644
--- a/lib/linear_weighted_ma.c
+++ b/lib/linear_weighted_ma.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_linear_weighted_ma_p = { .n_inputs = 1, .n_outputs = 1,
 uint_t ts_linear_weighted_ma_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_linear_weighted_ma_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_linear_weighted_ma_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_linear_weighted_ma(
@@ -33,7 +33,7 @@ int ts_linear_weighted_ma(
 {
 	TS_PROLOGUE( ts_linear_weighted_ma_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_linear_weighted_ma_params_t *)c)->k;
+    uint_t k = ((ts_linear_weighted_ma_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t w_sum = 0;
diff --git a/lib/logarithm.c b/lib/logarithm.c
index 7451976..9ca98a6 100755
--- a/lib/logarithm.c
+++ b/lib/logarithm.c
@@ -36,8 +36,8 @@ int ts_logarithm(
 {
 	TS_PROLOGUE( ts_logarithm_p );
 	if ( !c ) return -1;
-	fp_t b = ((ts_logarithm_params_t *)c)->b;
-	if (b == 0 || b == 1.0) return -1;
+	fp_t b = ((ts_logarithm_params_t const *)c)->b;
+	if (b <= 0 || b == 1.0 || isnan(b) || isinf(b)) return -1;
 
     b = _ts_reciprocal( log( b ) );
 
diff --git a/lib/lowest_low.c b/lib/lowest_low.c
index d8ac284..687cdeb 100644
--- a/lib/lowest_low.c
+++ b/lib/lowest_low.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_lowest_low_p = { .n_inputs = 4, .n_outputs = 1, .n_const
 uint_t ts_lowest_low_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_lowest_low_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_lowest_low_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_lowest_low(
@@ -33,7 +33,7 @@ int ts_lowest_low(
 {
 	TS_PROLOGUE( ts_lowest_low_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_lowest_low_params_t *)c)->k;
+	uint_t k = ((ts_lowest_low_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	fp_t min_val = ts_l( x, 0 );
diff --git a/lib/macd.c b/lib/macd.c
index 362f251..63db964 100644
--- a/lib/macd.c
+++ b/lib/macd.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_macd_p = { .n_inputs = 1, .n_outputs = 3, .n_constants =
 uint_t ts_macd_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? (uint_t)(((ts_macd_params_t *)c)->slow_k + ((ts_macd_params_t *)c)->signal_k - 2) : 0 );
+	return ( c ? (uint_t)(((ts_macd_params_t const *)c)->slow_k + ((ts_macd_params_t const *)c)->signal_k - 2) : 0 );
 }
 
 int ts_macd(
@@ -37,13 +37,13 @@ int ts_macd(
 	TS_PROLOGUE( ts_macd_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	fp_t fast_k = ((ts_macd_params_t *)c)->fast_k;
-	fp_t slow_k = ((ts_macd_params_t *)c)->slow_k;
-	fp_t signal_k = ((ts_macd_params_t *)c)->signal_k;
+	fp_t fast_k = ((ts_macd_params_t const *)c)->fast_k;
+	fp_t slow_k = ((ts_macd_params_t const *)c)->slow_k;
+	fp_t signal_k = ((ts_macd_params_t const *)c)->signal_k;
 
 	if (fast_k < 1 || slow_k < 1 || signal_k < 1) return -1;
 	if (isnan(fast_k) || isnan(slow_k) || isnan(signal_k)) return -1;
-	if (n == 0) return -1;
+	if (isinf(fast_k) || isinf(slow_k) || isinf(signal_k)) return -1;
 
 	fp_t fast_a = 2.0 / (fast_k + 1.0);
 	fp_t slow_a = 2.0 / (slow_k + 1.0);
@@ -52,9 +52,17 @@ int ts_macd(
 	fp_t fast_ema = x[0][0];
 	fp_t slow_ema = x[0][0];
 
+	if (slow_k > (fp_t)UINT64_MAX || signal_k > (fp_t)UINT64_MAX) return -1;
 	uint_t total_offset = (uint_t)(slow_k + signal_k - 2);
 	if (n <= total_offset) return -1;
 
+	// Initialize warm-up period to NAN
+	for (uint_t i = 0; i < total_offset; i++) {
+		y[0][i] = NAN;
+		y[1][i] = NAN;
+		y[2][i] = NAN;
+	}
+
 	// Compute EMAs up to total_offset
 	for( uint_t i = 1; i <= total_offset; ++i )
 	{
diff --git a/lib/maximum.c b/lib/maximum.c
index f4d124a..0f1539b 100755
--- a/lib/maximum.c
+++ b/lib/maximum.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_maximum_p = { .n_inputs = 1, .n_outputs = 1, .n_constant
 uint_t ts_maximum_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_maximum_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_maximum_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_maximum(
@@ -32,7 +32,7 @@ int ts_maximum(
 {
 	TS_PROLOGUE( ts_maximum_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_maximum_params_t *)c)->k;
+	uint_t k = ((ts_maximum_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = k - 1;
diff --git a/lib/mesa_sine_wave.c b/lib/mesa_sine_wave.c
index 8ed5fa6..91fbcd2 100644
--- a/lib/mesa_sine_wave.c
+++ b/lib/mesa_sine_wave.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_mesa_sine_wave_p = { .n_inputs = 1, .n_outputs = 2, .n_c
 uint_t ts_mesa_sine_wave_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_mesa_sine_wave_params_t *)c)->k : 0 );
+	return ( c ? ((ts_mesa_sine_wave_params_t const *)c)->k : 0 );
 }
 
 int ts_mesa_sine_wave(
@@ -35,64 +35,64 @@ int ts_mesa_sine_wave(
 {
 	TS_PROLOGUE( ts_mesa_sine_wave_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_mesa_sine_wave_params_t *)c)->k;
+    uint_t k = ((ts_mesa_sine_wave_params_t const *)c)->k;
     if (k < 2 || n < k) return -1;
 
-    fp_t *sma = calloc(n, sizeof(fp_t));
-    if (!sma) return -1;
+ fp_t *sma = calloc( n, sizeof( fp_t ) );
+    if ( !sma ) return -1;
 
-    for (uint_t i = 0; i < n; ++i)
+    for ( uint_t i = 0; i < n; ++i )
     {
-        if (i < k - 1)
+        if ( i < k - 1 )
         {
             fp_t sum = 0;
-            for (uint_t j = 0; j <= i; ++j)
+            for ( uint_t j = 0; j <= i; ++j )
                 sum += x[0][j];
-            sma[i] = sum / (i + 1);
+            sma[i] = sum / (fp_t)( i + 1 );
         }
         else
         {
             fp_t sum = 0;
-            for (uint_t j = i - k + 1; j <= i; ++j)
+            for ( uint_t j = i - k + 1; j <= i; ++j )
                 sum += x[0][j];
-            sma[i] = sum / k;
+            sma[i] = sum / (fp_t)k;
         }
     }
 
     fp_t ema_roc = 0;
     uint_t ema_period = 5;
-    fp_t ema_a = 2.0 / (ema_period + 1);
+    fp_t ema_a = 2.0 / ( (fp_t)ema_period + 1 );
     fp_t phase = 0;
     int_t first = 1;
 
-    for (uint_t j = 0; j < n && j < k; ++j) { y[0][j] = 0; y[1][j] = 0; }
-    for (uint_t i = k; i < n; ++i)
+    for ( uint_t j = 0; j < n && j < k; ++j ) { y[0][j] = 0; y[1][j] = 0; }
+    for ( uint_t i = k; i < n; ++i )
     {
         fp_t roc = sma[i] - sma[i - 2];
 
-        if (first)
+        if ( first )
         {
             ema_roc = roc;
             first = 0;
         }
         else
         {
-            ema_roc = ema_roc + ema_a * (roc - ema_roc);
+            ema_roc = ema_roc + ema_a * ( roc - ema_roc );
         }
 
         fp_t smoothed = ema_roc;
-        if (smoothed > 1.0) smoothed = 1.0;
-        if (smoothed < 0.01) smoothed = 0.01;
+        if ( smoothed > 1.0 ) smoothed = 1.0;
+        if ( smoothed < 0.01 ) smoothed = 0.01;
 
         fp_t wperiod = 2 * PI / smoothed;
-        if (wperiod < 5) wperiod = 5;
-        if (wperiod > 12) wperiod = 12;
+        if ( wperiod < 5 ) wperiod = 5;
+        if ( wperiod > 12 ) wperiod = 12;
 
-        if (smoothed >= 1.0)
+        if ( smoothed >= 1.0 )
         {
             phase = 0;
         }
-        else if (smoothed <= 0.01)
+        else if ( smoothed <= 0.01 )
         {
             phase = 2 * PI;
         }
@@ -100,13 +100,13 @@ int ts_mesa_sine_wave(
         {
             phase += 2 * PI / wperiod;
         }
-        while (phase > 2 * PI) phase -= 2 * PI;
+        while ( phase > 2 * PI ) phase -= 2 * PI;
 
-        y[0][i] = cos(phase);
-        y[1][i] = cos(phase + PI / 2);
+        y[0][i] = cos( phase );
+        y[1][i] = cos( phase + PI / 2 );
     }
 
-    free(sma);
+    free( sma );
 	return 0;
 }
 
diff --git a/lib/mfi.c b/lib/mfi.c
index c93803c..155c347 100644
--- a/lib/mfi.c
+++ b/lib/mfi.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_mfi_p = { .n_inputs = 5, .n_outputs = 1, .n_constants =
 uint_t ts_mfi_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_mfi_params_t *)c)->k : 0 );
+	return ( c ? ((ts_mfi_params_t const *)c)->k : 0 );
 }
 
 int ts_mfi(
@@ -34,7 +34,7 @@ int ts_mfi(
 {
 	TS_PROLOGUE( ts_mfi_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_mfi_params_t *)c)->k;
+	uint_t k = ((ts_mfi_params_t const *)c)->k;
 	if (k == 0 || n <= k) return -1;
 
 	fp_t *tp = calloc( n, sizeof( fp_t ) );
diff --git a/lib/midpoint.c b/lib/midpoint.c
index c28cdff..da24eba 100644
--- a/lib/midpoint.c
+++ b/lib/midpoint.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_midpoint_p = { .n_inputs = 1, .n_outputs = 1, .n_constan
 uint_t ts_midpoint_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_midpoint_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_midpoint_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_midpoint(
@@ -33,7 +33,7 @@ int ts_midpoint(
 {
 	TS_PROLOGUE( ts_midpoint_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_midpoint_params_t *)c)->k;
+	uint_t k = ((ts_midpoint_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/midprice.c b/lib/midprice.c
index d26a58e..8c8dfe0 100644
--- a/lib/midprice.c
+++ b/lib/midprice.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_midprice_p = { .n_inputs = 1, .n_outputs = 1, .n_constan
 uint_t ts_midprice_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_midprice_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_midprice_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_midprice(
@@ -33,7 +33,7 @@ int ts_midprice(
 {
 	TS_PROLOGUE( ts_midprice_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_midprice_params_t *)c)->k;
+	uint_t k = ((ts_midprice_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/minimum.c b/lib/minimum.c
index d2ba15f..5a2814c 100755
--- a/lib/minimum.c
+++ b/lib/minimum.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_minimum_p = { .n_inputs = 1, .n_outputs = 1, .n_constant
 uint_t ts_minimum_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_minimum_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_minimum_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_minimum(
@@ -32,7 +32,7 @@ int ts_minimum(
 {
 	TS_PROLOGUE( ts_minimum_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_minimum_params_t *)c)->k;
+	uint_t k = ((ts_minimum_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = k - 1;
diff --git a/lib/minmax.c b/lib/minmax.c
index 4bee598..8763266 100644
--- a/lib/minmax.c
+++ b/lib/minmax.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_minmax_p = { .n_inputs = 1, .n_outputs = 2, .n_constants
 uint_t ts_minmax_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_minmax_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_minmax_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_minmax(
@@ -33,7 +33,7 @@ int ts_minmax(
 {
 	TS_PROLOGUE( ts_minmax_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_minmax_params_t *)c)->k;
+    uint_t k = ((ts_minmax_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/missing_bar_count.c b/lib/missing_bar_count.c
index e6f548e..d001a5f 100644
--- a/lib/missing_bar_count.c
+++ b/lib/missing_bar_count.c
@@ -34,8 +34,7 @@ int ts_missing_bar_count(
 {
 	TS_PROLOGUE( ts_missing_bar_count_p );
 	if ( !c ) return -1;
-	if (n == 0) return -1;
-	fp_t threshold = ((ts_missing_bar_count_params_t *)c)->threshold;
+	fp_t threshold = ((ts_missing_bar_count_params_t const *)c)->threshold;
 
 	y[0][0] = 0;
 
diff --git a/lib/momentum.c b/lib/momentum.c
index f0d89fd..8e1dcf4 100644
--- a/lib/momentum.c
+++ b/lib/momentum.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_momentum_p = { .n_inputs = 1, .n_outputs = 1, .n_constan
 uint_t ts_momentum_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_momentum_params_t *)c)->k : 0 );
+	return ( c ? ((ts_momentum_params_t const *)c)->k : 0 );
 }
 
 int ts_momentum(
@@ -34,7 +34,7 @@ int ts_momentum(
 	TS_PROLOGUE( ts_momentum_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_momentum_params_t *)c)->k;
+	uint_t k = ((ts_momentum_params_t const *)c)->k;
 
 	for( uint_t i = k; i < n; ++i )
 	{
diff --git a/lib/moving_linear_regression.c b/lib/moving_linear_regression.c
index ceb34d5..66b750c 100644
--- a/lib/moving_linear_regression.c
+++ b/lib/moving_linear_regression.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_moving_linear_regression_p = { .n_inputs = 1, .n_outputs
 uint_t ts_moving_linear_regression_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_moving_linear_regression_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_moving_linear_regression_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_moving_linear_regression(
@@ -33,7 +33,7 @@ int ts_moving_linear_regression(
 {
 	TS_PROLOGUE( ts_moving_linear_regression_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_moving_linear_regression_params_t *)c)->k;
+    uint_t k = ((ts_moving_linear_regression_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_x2 = 0;
diff --git a/lib/moving_linear_regression_r2.c b/lib/moving_linear_regression_r2.c
index 3015a25..71eb081 100644
--- a/lib/moving_linear_regression_r2.c
+++ b/lib/moving_linear_regression_r2.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_moving_linear_regression_r2_p = { .n_inputs = 1, .n_outp
 uint_t ts_moving_linear_regression_r2_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_moving_linear_regression_r2_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_moving_linear_regression_r2_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_moving_linear_regression_r2(
@@ -34,7 +34,7 @@ int ts_moving_linear_regression_r2(
 {
 	TS_PROLOGUE( ts_moving_linear_regression_r2_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_moving_linear_regression_r2_params_t *)c)->k;
+    uint_t k = ((ts_moving_linear_regression_r2_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum_x = 0, sum_x2 = 0;
diff --git a/lib/natr.c b/lib/natr.c
index ce58bb1..724e068 100644
--- a/lib/natr.c
+++ b/lib/natr.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_natr_p = { .n_inputs = 4, .n_outputs = 1, .n_constants =
 uint_t ts_natr_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_natr_params_t *)c)->k : 0 );
+	return ( c ? ((ts_natr_params_t const *)c)->k : 0 );
 }
 
 int ts_natr(
@@ -36,10 +36,14 @@ int ts_natr(
 {
 	TS_PROLOGUE( ts_natr_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_natr_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_natr_params_t const *)c)->k;
 	if (k == 0) return -1;
 	if (n < k + 1) return -1;
 
+	for( uint_t i = 0; i < k; ++i )
+		y[0][i] = NAN;
+
 	for( uint_t i = k; i < n; ++i )
 	{
 		fp_t tr_sum = 0;
diff --git a/lib/nvi.c b/lib/nvi.c
index f4d3397..c38238d 100644
--- a/lib/nvi.c
+++ b/lib/nvi.c
@@ -30,7 +30,6 @@ int ts_nvi(
 {
 	TS_PROLOGUE( ts_nvi_p );
 	(void)c;
-    if (n == 0) return -1;
 
     fp_t nvi = 1000;
 
diff --git a/lib/obv.c b/lib/obv.c
index 3765ba3..33bb7a7 100644
--- a/lib/obv.c
+++ b/lib/obv.c
@@ -31,7 +31,6 @@ int ts_obv(
 	TS_PROLOGUE( ts_obv_p );
 	(void)c;
 	TS_CHECK_INPUT(x, x_n, n);
-    if (n == 0) return -1;
 
     fp_t obv = 0;
     y[0][0] = 0;
diff --git a/lib/on_balance_volume_rate.c b/lib/on_balance_volume_rate.c
index 7183c23..242f00a 100644
--- a/lib/on_balance_volume_rate.c
+++ b/lib/on_balance_volume_rate.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_on_balance_volume_rate_p = { .n_inputs = 5, .n_outputs =
 uint_t ts_on_balance_volume_rate_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? (uint_t)((ts_on_balance_volume_rate_params_t *)c)->f0 + 1 : 0 );
+	return ( c ? (uint_t)((ts_on_balance_volume_rate_params_t const *)c)->f0 + 1 : 0 );
 }
 
 int ts_on_balance_volume_rate(
@@ -34,7 +34,7 @@ int ts_on_balance_volume_rate(
 {
 	TS_PROLOGUE( ts_on_balance_volume_rate_p );
 	if ( !c ) return -1;
-    uint_t k = (uint_t)((ts_on_balance_volume_rate_params_t *)c)->f0;
+    uint_t k = (uint_t)((ts_on_balance_volume_rate_params_t const *)c)->f0;
     if (k == 0 || k >= n) return -1;
 
     fp_t obv = 0;
diff --git a/lib/oscillator_cross.c b/lib/oscillator_cross.c
index 0c6c5f8..1510738 100644
--- a/lib/oscillator_cross.c
+++ b/lib/oscillator_cross.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_oscillator_cross_p = { .n_inputs = 1, .n_outputs = 1, .n
 uint_t ts_oscillator_cross_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? (uint_t)((ts_oscillator_cross_params_t *)c)->slow : 0 );
+	return ( c ? (uint_t)((ts_oscillator_cross_params_t const *)c)->slow : 0 );
 }
 
 int ts_oscillator_cross(
@@ -34,10 +34,9 @@ int ts_oscillator_cross(
 {
 	TS_PROLOGUE( ts_oscillator_cross_p );
 	if ( !c ) return -1;
-    fp_t const fast = ((ts_oscillator_cross_params_t *)c)->fast;
-    fp_t const slow = ((ts_oscillator_cross_params_t *)c)->slow;
+    fp_t const fast = ((ts_oscillator_cross_params_t const *)c)->fast;
+    fp_t const slow = ((ts_oscillator_cross_params_t const *)c)->slow;
     if (fast == 0 || slow == 0) return -1;
-    if (n == 0) return -1;
     fp_t const fast_a = 1.0 / fast;
     fp_t const slow_a = 1.0 / slow;
     fp_t fast_e = x[0][0];
diff --git a/lib/osma.c b/lib/osma.c
index a5a2756..3698b09 100644
--- a/lib/osma.c
+++ b/lib/osma.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_osma_p = { .n_inputs = 5, .n_outputs = 1, .n_constants =
 uint_t ts_osma_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? (uint_t)((ts_osma_params_t *)c)->slow_k : 0 );
+	return ( c ? (uint_t)((ts_osma_params_t const *)c)->slow_k : 0 );
 }
 
 int ts_osma(
@@ -35,12 +35,11 @@ int ts_osma(
 {
 	TS_PROLOGUE( ts_osma_p );
 	if ( !c ) return -1;
-	fp_t fast_k = ((ts_osma_params_t *)c)->fast_k;
-	fp_t slow_k = ((ts_osma_params_t *)c)->slow_k;
-	fp_t signal_k = ((ts_osma_params_t *)c)->signal_k;
+	fp_t fast_k = ((ts_osma_params_t const *)c)->fast_k;
+	fp_t slow_k = ((ts_osma_params_t const *)c)->slow_k;
+	fp_t signal_k = ((ts_osma_params_t const *)c)->signal_k;
 
 	if (fast_k == 0 || slow_k == 0 || signal_k == 0) return -1;
-	if (n == 0) return -1;
 
 	fp_t fast_a = 1.0 / fast_k;
 	fp_t slow_a = 1.0 / slow_k;
diff --git a/lib/parabolic_sar.c b/lib/parabolic_sar.c
index ff84834..cd699aa 100644
--- a/lib/parabolic_sar.c
+++ b/lib/parabolic_sar.c
@@ -35,12 +35,11 @@ int ts_parabolic_sar(
 {
 	TS_PROLOGUE( ts_parabolic_sar_p );
 	if ( !c ) return -1;
-    fp_t step = ((ts_parabolic_sar_params_t *)c)->step;
-    fp_t max_af = ((ts_parabolic_sar_params_t *)c)->max_af;
+    fp_t step = ((ts_parabolic_sar_params_t const *)c)->step;
+    fp_t max_af = ((ts_parabolic_sar_params_t const *)c)->max_af;
     if (step <= 0 || max_af <= 0) return -1;
     if (isnan(step) || isnan(max_af)) return -1;
     if (step > max_af) return -1;
-    if (n == 0) return -1;
 
     int_t trend = 1;
     fp_t sar = ts_l( x, 0 );
diff --git a/lib/performance_ratio.c b/lib/performance_ratio.c
index ffd0ece..a429b8b 100644
--- a/lib/performance_ratio.c
+++ b/lib/performance_ratio.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_performance_ratio_p = { .n_inputs = 1, .n_outputs = 1, .
 uint_t ts_performance_ratio_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_performance_ratio_params_t *)c)->k : 0 );
+	return ( c ? ((ts_performance_ratio_params_t const *)c)->k : 0 );
 }
 
 int ts_performance_ratio(
@@ -34,8 +34,8 @@ int ts_performance_ratio(
 {
 	TS_PROLOGUE( ts_performance_ratio_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_performance_ratio_params_t *)c)->k;
-    if (k <= 1 || n == 0) return -1;
+    uint_t k = ((ts_performance_ratio_params_t const *)c)->k;
+    if (k <= 1) return -1;
 
     fp_t factor = (fp_t)k / (k - 1);
 
diff --git a/lib/poisson_pdf.c b/lib/poisson_pdf.c
index e1e2d59..60a62ac 100644
--- a/lib/poisson_pdf.c
+++ b/lib/poisson_pdf.c
@@ -34,7 +34,7 @@ int ts_poisson_pdf(
 {
 	TS_PROLOGUE( ts_poisson_pdf_p );
 	if ( !c ) return -1;
-	fp_t lambda = ((ts_poisson_pdf_params_t *)c)->lambda;
+	fp_t lambda = ((ts_poisson_pdf_params_t const *)c)->lambda;
 	if (lambda < 0.0 || isnan(lambda) || isinf(lambda)) return -1;
 	for( uint_t i = 0; i < n; ++i )
 	{
diff --git a/lib/polynomial.c b/lib/polynomial.c
index 2914fe6..82d8fba 100644
--- a/lib/polynomial.c
+++ b/lib/polynomial.c
@@ -33,7 +33,7 @@ int ts_polynomial(
     {
         fp_t base = x[0][i];
         fp_t exponent = x[1][i];
-        if( base < 0.0 && exponent != (fp_t)(long)exponent ) { y[0][i] = 0; continue; }
+        if( base < 0.0 && exponent != (fp_t)(long)exponent ) { y[0][i] = NAN; continue; }
         y[0][i] = pow(base, exponent);
     }
 	return 0;
diff --git a/lib/power.c b/lib/power.c
index 41bb644..1d9c8cd 100755
--- a/lib/power.c
+++ b/lib/power.c
@@ -36,7 +36,7 @@ int ts_power(
 {
 	TS_PROLOGUE( ts_power_p );
 	if ( !c ) return -1;
-	fp_t r = ((ts_power_params_t *)c)->r;
+	fp_t r = ((ts_power_params_t const *)c)->r;
 
 	for( uint_t i = 0; i < n; ++i )
 	{
diff --git a/lib/ppo.c b/lib/ppo.c
index b2b3bbf..f367c28 100644
--- a/lib/ppo.c
+++ b/lib/ppo.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_ppo_p = { .n_inputs = 5, .n_outputs = 2, .n_constants =
 uint_t ts_ppo_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? (uint_t)(((ts_ppo_params_t *)c)->slow_k + ((ts_ppo_params_t *)c)->signal_k - 2) : 0 );
+	return ( c ? (uint_t)(((ts_ppo_params_t const *)c)->slow_k + ((ts_ppo_params_t const *)c)->signal_k - 2) : 0 );
 }
 
 int ts_ppo(
@@ -35,12 +35,11 @@ int ts_ppo(
 {
 	TS_PROLOGUE( ts_ppo_p );
 	if ( !c ) return -1;
-	fp_t fast_k = ((ts_ppo_params_t *)c)->fast_k;
-	fp_t slow_k = ((ts_ppo_params_t *)c)->slow_k;
-	fp_t signal_k = ((ts_ppo_params_t *)c)->signal_k;
+	fp_t fast_k = ((ts_ppo_params_t const *)c)->fast_k;
+	fp_t slow_k = ((ts_ppo_params_t const *)c)->slow_k;
+	fp_t signal_k = ((ts_ppo_params_t const *)c)->signal_k;
 
 	if (fast_k == 0 || slow_k == 0 || signal_k == 0) return -1;
-	if (n == 0) return -1;
 
 	fp_t fast_a = 1.0 / fast_k;
 	fp_t slow_a = 1.0 / slow_k;
diff --git a/lib/pretty_good_oscillator.c b/lib/pretty_good_oscillator.c
index 65a05c2..2dbc6f1 100644
--- a/lib/pretty_good_oscillator.c
+++ b/lib/pretty_good_oscillator.c
@@ -30,7 +30,7 @@ int ts_pretty_good_oscillator(
 {
 	TS_PROLOGUE( ts_pretty_good_oscillator_p );
 	(void)c;
-    if (n == 0) return -1;
+
     fp_t ema14 = x[0][0];
     fp_t ema30 = x[0][0];
     fp_t ema90 = x[0][0];
diff --git a/lib/price_channel.c b/lib/price_channel.c
index 9aba070..4a3129c 100644
--- a/lib/price_channel.c
+++ b/lib/price_channel.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_price_channel_p = { .n_inputs = 1, .n_outputs = 3, .n_co
 uint_t ts_price_channel_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_price_channel_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_price_channel_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_price_channel(
@@ -33,7 +33,7 @@ int ts_price_channel(
 {
 	TS_PROLOGUE( ts_price_channel_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_price_channel_params_t *)c)->k;
+    uint_t k = ((ts_price_channel_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/price_momentum_oscillator.c b/lib/price_momentum_oscillator.c
index b03f350..d92fccb 100644
--- a/lib/price_momentum_oscillator.c
+++ b/lib/price_momentum_oscillator.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_price_momentum_oscillator_p = { .n_inputs = 1, .n_output
 uint_t ts_price_momentum_oscillator_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_price_momentum_oscillator_params_t *)c)->k : 0 );
+	return ( c ? ((ts_price_momentum_oscillator_params_t const *)c)->k : 0 );
 }
 
 int ts_price_momentum_oscillator(
@@ -33,7 +33,7 @@ int ts_price_momentum_oscillator(
 {
 	TS_PROLOGUE( ts_price_momentum_oscillator_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_price_momentum_oscillator_params_t *)c)->k;
+    uint_t k = ((ts_price_momentum_oscillator_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for (uint_t i = k; i < n; ++i)
diff --git a/lib/price_rate_of_change.c b/lib/price_rate_of_change.c
index 8f26548..4dc9834 100644
--- a/lib/price_rate_of_change.c
+++ b/lib/price_rate_of_change.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_price_rate_of_change_p = { .n_inputs = 1, .n_outputs = 1
 uint_t ts_price_rate_of_change_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_price_rate_of_change_params_t *)c)->k : 0 );
+	return ( c ? ((ts_price_rate_of_change_params_t const *)c)->k : 0 );
 }
 
 int ts_price_rate_of_change(
@@ -33,7 +33,7 @@ int ts_price_rate_of_change(
 {
 	TS_PROLOGUE( ts_price_rate_of_change_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_price_rate_of_change_params_t *)c)->k;
+    uint_t k = ((ts_price_rate_of_change_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for (uint_t i = k; i < n; ++i)
diff --git a/lib/prime_number_bands.c b/lib/prime_number_bands.c
index ac94e7b..bb01c2c 100644
--- a/lib/prime_number_bands.c
+++ b/lib/prime_number_bands.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_prime_number_bands_p = { .n_inputs = 1, .n_outputs = 3,
 uint_t ts_prime_number_bands_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_prime_number_bands_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_prime_number_bands_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_prime_number_bands(
@@ -34,7 +34,7 @@ int ts_prime_number_bands(
 {
 	TS_PROLOGUE( ts_prime_number_bands_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_prime_number_bands_params_t *)c)->k;
+	uint_t k = ((ts_prime_number_bands_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/prings_special_k.c b/lib/prings_special_k.c
index 91a40ba..9191567 100644
--- a/lib/prings_special_k.c
+++ b/lib/prings_special_k.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_prings_special_k_p = { .n_inputs = 4, .n_outputs = 2, .n
 uint_t ts_prings_special_k_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_prings_special_k_params_t *)c)->k1 > 0 && ((ts_prings_special_k_params_t *)c)->k2 > 0 ? ((ts_prings_special_k_params_t *)c)->k1 + ((ts_prings_special_k_params_t *)c)->k2 - 2 : 0 : 0 );
+	return ( c ? ((ts_prings_special_k_params_t const *)c)->k1 > 0 && ((ts_prings_special_k_params_t const *)c)->k2 > 0 ? ((ts_prings_special_k_params_t const *)c)->k1 + ((ts_prings_special_k_params_t const *)c)->k2 - 2 : 0 : 0 );
 }
 
 int ts_prings_special_k(
@@ -34,8 +34,8 @@ int ts_prings_special_k(
 {
 	TS_PROLOGUE( ts_prings_special_k_p );
 	if ( !c ) return -1;
-	uint_t k1 = ((ts_prings_special_k_params_t *)c)->k1;
-	uint_t k2 = ((ts_prings_special_k_params_t *)c)->k2;
+	uint_t k1 = ((ts_prings_special_k_params_t const *)c)->k1;
+	uint_t k2 = ((ts_prings_special_k_params_t const *)c)->k2;
 	if (k1 == 0 || k2 == 0) return -1;
 
 	fp_t ema = 0;
diff --git a/lib/psychological_line.c b/lib/psychological_line.c
index 35fd912..86ebcd3 100644
--- a/lib/psychological_line.c
+++ b/lib/psychological_line.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_psychological_line_p = { .n_inputs = 4, .n_outputs = 1,
 uint_t ts_psychological_line_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_psychological_line_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_psychological_line_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_psychological_line(
@@ -33,7 +33,7 @@ int ts_psychological_line(
 {
 	TS_PROLOGUE( ts_psychological_line_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_psychological_line_params_t *)c)->k;
+    uint_t k = ((ts_psychological_line_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t sum = 0;
diff --git a/lib/pvi.c b/lib/pvi.c
index 26265d5..55ecb84 100644
--- a/lib/pvi.c
+++ b/lib/pvi.c
@@ -30,9 +30,8 @@ int ts_pvi(
 {
 	TS_PROLOGUE( ts_pvi_p );
 	(void)c;
-    fp_t pvi = 1000;
 
-    if (n == 0) return -1;
+    fp_t pvi = 1000;
 
     y[0][0] = pvi;
 
diff --git a/lib/qstick.c b/lib/qstick.c
index d2f4361..dd7d7da 100644
--- a/lib/qstick.c
+++ b/lib/qstick.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_qstick_p = { .n_inputs = 4, .n_outputs = 1, .n_constants
 uint_t ts_qstick_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_qstick_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_qstick_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_qstick(
@@ -33,7 +33,7 @@ int ts_qstick(
 {
 	TS_PROLOGUE( ts_qstick_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_qstick_params_t *)c)->k;
+    uint_t k = ((ts_qstick_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/rainbow_oscillator.c b/lib/rainbow_oscillator.c
index 1a56b55..463577f 100644
--- a/lib/rainbow_oscillator.c
+++ b/lib/rainbow_oscillator.c
@@ -58,7 +58,7 @@ int ts_rainbow_oscillator(
 				max_ma = ma_values[p];
 		}
 
-		if( max_ma == min_ma )
+		if( fabs(max_ma - min_ma) < TS_FILL_ZERO_THRESHOLD )
 			y[0][i] = 0;
 		else
 			y[0][i] = ( x[0][i] - min_ma ) / ( max_ma - min_ma ) * 100.0;
diff --git a/lib/random_walk_index.c b/lib/random_walk_index.c
index b4375e5..aa8e5f5 100644
--- a/lib/random_walk_index.c
+++ b/lib/random_walk_index.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_random_walk_index_p = { .n_inputs = 1, .n_outputs = 1, .
 uint_t ts_random_walk_index_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_random_walk_index_params_t *)c)->k : 0 );
+	return ( c ? ((ts_random_walk_index_params_t const *)c)->k : 0 );
 }
 
 int ts_random_walk_index(
@@ -34,7 +34,7 @@ int ts_random_walk_index(
 {
 	TS_PROLOGUE( ts_random_walk_index_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_random_walk_index_params_t *)c)->k;
+	uint_t k = ((ts_random_walk_index_params_t const *)c)->k;
 	if (k == 0 || n < k + 1) return -1;
 
 	fp_t sum_abs = 0;
diff --git a/lib/rank.c b/lib/rank.c
index 392b63f..200bbbe 100644
--- a/lib/rank.c
+++ b/lib/rank.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_rank_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_rank_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_rank_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_rank_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_rank(
@@ -33,7 +33,7 @@ int ts_rank(
 {
 	TS_PROLOGUE( ts_rank_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_rank_params_t *)c)->k;
+    uint_t k = ((ts_rank_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/ratio.c b/lib/ratio.c
index 8568476..813d46c 100755
--- a/lib/ratio.c
+++ b/lib/ratio.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_ratio_p = { .n_inputs = 1, .n_outputs = 1, .n_constants
 uint_t ts_ratio_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_ratio_params_t *)c)->k : 0 );
+	return ( c ? ((ts_ratio_params_t const *)c)->k : 0 );
 }
 
 int ts_ratio(
@@ -35,7 +35,7 @@ int ts_ratio(
 {
 	TS_PROLOGUE( ts_ratio_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_ratio_params_t *)c)->k;
+	uint_t k = ((ts_ratio_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 	
 	uint_t xi = k;
diff --git a/lib/ravi.c b/lib/ravi.c
index fcb3095..efe8353 100644
--- a/lib/ravi.c
+++ b/lib/ravi.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_ravi_p = { .n_inputs = 4, .n_outputs = 2, .n_constants =
 uint_t ts_ravi_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_ravi_params_t *)c)->k + (uint_t)((ts_ravi_params_t *)c)->k2 - 2 : 0 );
+	return ( c ? ((ts_ravi_params_t const *)c)->k + (uint_t)((ts_ravi_params_t const *)c)->k2 - 2 : 0 );
 }
 
 int ts_ravi(
@@ -36,19 +36,19 @@ int ts_ravi(
 {
 	TS_PROLOGUE( ts_ravi_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_ravi_params_t *)c)->k;
-    fp_t k2 = ((ts_ravi_params_t *)c)->k2;
+    uint_t k = ((ts_ravi_params_t const *)c)->k;
+    fp_t k2 = ((ts_ravi_params_t const *)c)->k2;
 
-    if( k == 0 || k2 == 0 ) return -1;
+    if( k == 0 || k2 <= 0 || isnan(k2) || isinf(k2) ) return -1;
 
-    fp_t *num_buf = calloc( n, sizeof( fp_t ) );
+ fp_t *num_buf = calloc( n, sizeof( fp_t ) );
     fp_t *den_buf = calloc( n, sizeof( fp_t ) );
     if( !num_buf || !den_buf ) { free( num_buf ); free( den_buf ); return -1; }
 
     for( uint_t i = 0; i < n; ++i )
     {
-        num_buf[i] = (x[3][i] - x[0][i]) + (x[3][i] - (i > 0 ? x[3][i - 1] : x[3][i]));
-        den_buf[i] = fabs(x[1][i] - x[2][i]) + fabs(x[3][i] - x[0][i]);
+        num_buf[i] = ( x[3][i] - x[0][i] ) + ( x[3][i] - ( i > 0 ? x[3][i - 1] : x[3][i] ) );
+        den_buf[i] = fabs( x[1][i] - x[2][i] ) + fabs( x[3][i] - x[0][i] );
     }
 
     fp_t num_sum = 0;
@@ -65,14 +65,14 @@ int ts_ravi(
     fp_t sig_a = 1.0 / k2;
     uint_t offset = k + (uint_t)k2 - 2;
 
-    for (uint_t i = 0; i < offset; ++i) { y[0][i] = 0; y[1][i] = 0; }
+    for ( uint_t i = 0; i < offset; ++i ) { y[0][i] = 0; y[1][i] = 0; }
 
     for( uint_t i = k; i < n; ++i )
     {
         num_sum = num_sum - num_buf[i - k] + num_buf[i];
         den_sum = den_sum - den_buf[i - k] + den_buf[i];
         rvi = ( den_sum != 0 ) ? num_sum / den_sum : 0;
-        sig = sig + sig_a * (rvi - sig);
+        sig = sig + sig_a * ( rvi - sig );
 
         if( i >= offset )
         {
diff --git a/lib/regression_linear_least_squares.c b/lib/regression_linear_least_squares.c
index 49123bb..5e37e38 100755
--- a/lib/regression_linear_least_squares.c
+++ b/lib/regression_linear_least_squares.c
@@ -34,7 +34,7 @@ ts_parameter_t const ts_regression_linear_least_squares_p = { .n_inputs = 2, .n_
 uint_t ts_regression_linear_least_squares_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_regression_linear_least_squares_params_t *)c)->k : 0 );
+	return ( c ? ((ts_regression_linear_least_squares_params_t const *)c)->k : 0 );
 }
 
 int ts_regression_linear_least_squares(
@@ -45,7 +45,7 @@ int ts_regression_linear_least_squares(
 {
 	TS_PROLOGUE( ts_regression_linear_least_squares_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_regression_linear_least_squares_params_t *)c)->k;
+	uint_t k = ((ts_regression_linear_least_squares_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 	
 	uint_t xi = k;
diff --git a/lib/relative_volatility.c b/lib/relative_volatility.c
index 9682a2d..77b6968 100644
--- a/lib/relative_volatility.c
+++ b/lib/relative_volatility.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_relative_volatility_p = { .n_inputs = 1, .n_outputs = 1,
 uint_t ts_relative_volatility_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_relative_volatility_params_t *)c)->k - 1 : 0 );
+	return ( c ? ((ts_relative_volatility_params_t const *)c)->k - 1 : 0 );
 }
 
 int ts_relative_volatility(
@@ -34,7 +34,7 @@ int ts_relative_volatility(
 {
 	TS_PROLOGUE( ts_relative_volatility_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_relative_volatility_params_t *)c)->k;
+	uint_t k = ((ts_relative_volatility_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/roc.c b/lib/roc.c
index 3b45ecd..cfa16aa 100644
--- a/lib/roc.c
+++ b/lib/roc.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_roc_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_roc_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_roc_params_t *)c)->k : 0 );
+	return ( c ? ((ts_roc_params_t const *)c)->k : 0 );
 }
 
 int ts_roc(
@@ -34,7 +34,7 @@ int ts_roc(
 	TS_PROLOGUE( ts_roc_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_roc_params_t *)c)->k;
+	uint_t k = ((ts_roc_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k; i < n; ++i )
diff --git a/lib/rocp.c b/lib/rocp.c
index 6575d85..4a1ddad 100644
--- a/lib/rocp.c
+++ b/lib/rocp.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_rocp_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_rocp_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_rocp_params_t *)c)->k : 0 );
+	return ( c ? ((ts_rocp_params_t const *)c)->k : 0 );
 }
 
 int ts_rocp(
@@ -33,7 +33,7 @@ int ts_rocp(
 {
 	TS_PROLOGUE( ts_rocp_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_rocp_params_t *)c)->k;
+	uint_t k = ((ts_rocp_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k; i < n; ++i )
diff --git a/lib/rocr.c b/lib/rocr.c
index d11cb91..35a2351 100644
--- a/lib/rocr.c
+++ b/lib/rocr.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_rocr_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_rocr_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_rocr_params_t *)c)->k : 0 );
+	return ( c ? ((ts_rocr_params_t const *)c)->k : 0 );
 }
 
 int ts_rocr(
@@ -33,7 +33,7 @@ int ts_rocr(
 {
 	TS_PROLOGUE( ts_rocr_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_rocr_params_t *)c)->k;
+	uint_t k = ((ts_rocr_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k; i < n; ++i )
diff --git a/lib/rocr100.c b/lib/rocr100.c
index b90413f..22b6dbf 100644
--- a/lib/rocr100.c
+++ b/lib/rocr100.c
@@ -21,7 +21,7 @@ ts_parameter_t const ts_rocr100_p = { .n_inputs = 1, .n_outputs = 1, .n_constant
 uint_t ts_rocr100_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_rocr100_params_t *)c)->k : 0 );
+	return ( c ? ((ts_rocr100_params_t const *)c)->k : 0 );
 }
 
 int ts_rocr100(
@@ -32,7 +32,7 @@ int ts_rocr100(
 {
 	TS_PROLOGUE( ts_rocr100_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_rocr100_params_t *)c)->k;
+	uint_t k = ((ts_rocr100_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k; i < n; ++i )
diff --git a/lib/root.c b/lib/root.c
index a5e7dca..140a3c6 100755
--- a/lib/root.c
+++ b/lib/root.c
@@ -36,7 +36,7 @@ int ts_root(
 {
 	TS_PROLOGUE( ts_root_p );
 	if ( !c ) return -1;
-	fp_t r = ((ts_root_params_t *)c)->r;
+	fp_t r = ((ts_root_params_t const *)c)->r;
 	if (r == 0) return -1;
 
 	for( uint_t i = 0; i < n; ++i )
diff --git a/lib/rsi.c b/lib/rsi.c
index bf21c5e..4bc6e60 100644
--- a/lib/rsi.c
+++ b/lib/rsi.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_rsi_p = { .n_inputs = 1, .n_outputs = 1, .n_constants =
 uint_t ts_rsi_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_rsi_params_t *)c)->k : 0 );
+	return ( c ? ((ts_rsi_params_t const *)c)->k : 0 );
 }
 
 int ts_rsi(
@@ -37,7 +37,7 @@ int ts_rsi(
 	TS_PROLOGUE( ts_rsi_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_rsi_params_t *)c)->k;
+	uint_t k = ((ts_rsi_params_t const *)c)->k;
 	if (k == 0 || n <= k) return -1;
 
 	for (uint_t i = 0; i < k; ++i) y[0][i] = NAN;
diff --git a/lib/schaff_trend_cycle.c b/lib/schaff_trend_cycle.c
index f4584e6..0ff3e1c 100644
--- a/lib/schaff_trend_cycle.c
+++ b/lib/schaff_trend_cycle.c
@@ -35,9 +35,8 @@ int ts_schaff_trend_cycle(
 {
 	TS_PROLOGUE( ts_schaff_trend_cycle_p );
 	if ( !c ) return -1;
-    uint_t period = ((ts_schaff_trend_cycle_params_t *)c)->period;
+    uint_t period = ((ts_schaff_trend_cycle_params_t const *)c)->period;
     if (period == 0) period = 3;
-    if (n == 0) return -1;
     if (period > n) { for (uint_t j = 0; j < n; ++j) { y[0][j] = 0; y[1][j] = 0; } return 0; }
 
     uint_t fast = 10;
diff --git a/lib/shinohara_intensity_ratio.c b/lib/shinohara_intensity_ratio.c
index fcdd364..5476892 100644
--- a/lib/shinohara_intensity_ratio.c
+++ b/lib/shinohara_intensity_ratio.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_shinohara_intensity_ratio_p = { .n_inputs = 4, .n_output
 uint_t ts_shinohara_intensity_ratio_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_shinohara_intensity_ratio_params_t *)c)->k > 0 ? ((ts_shinohara_intensity_ratio_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_shinohara_intensity_ratio_params_t const *)c)->k > 0 ? ((ts_shinohara_intensity_ratio_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_shinohara_intensity_ratio(
@@ -35,7 +35,7 @@ int ts_shinohara_intensity_ratio(
 {
 	TS_PROLOGUE( ts_shinohara_intensity_ratio_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_shinohara_intensity_ratio_params_t *)c)->k;
+    uint_t k = ((ts_shinohara_intensity_ratio_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t *intensity = calloc( n, sizeof( fp_t ) );
diff --git a/lib/sigmoid.c b/lib/sigmoid.c
index 05ea126..33fd58b 100644
--- a/lib/sigmoid.c
+++ b/lib/sigmoid.c
@@ -44,10 +44,11 @@ int ts_sigmoid(
 {
 	TS_PROLOGUE( ts_sigmoid_p );
 	if ( !c ) return -1;
-	fp_t m = ((ts_sigmoid_params_t *)c)->m;
-	fp_t L = ((ts_sigmoid_params_t *)c)->L;
-	fp_t b = ((ts_sigmoid_params_t *)c)->b;
+	fp_t m = ((ts_sigmoid_params_t const *)c)->m;
+	fp_t L = ((ts_sigmoid_params_t const *)c)->L;
+	fp_t b = ((ts_sigmoid_params_t const *)c)->b;
 
+	if (L == 0 || isnan(L) || isinf(L) || isnan(m) || isinf(m)) return -1;
 	m = -( 4.0 * m ) / L;
     b = b - ( 0.5 * L );
 
diff --git a/lib/slope.c b/lib/slope.c
index ca4fd22..5005fff 100755
--- a/lib/slope.c
+++ b/lib/slope.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_slope_p = { .n_inputs = 1, .n_outputs = 1, .n_constants
 uint_t ts_slope_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_slope_params_t *)c)->k : 0 );
+	return ( c ? ((ts_slope_params_t const *)c)->k : 0 );
 }
 
 int ts_slope(
@@ -35,7 +35,7 @@ int ts_slope(
 {
 	TS_PROLOGUE( ts_slope_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_slope_params_t *)c)->k;
+	uint_t k = ((ts_slope_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = k;
diff --git a/lib/softplus.c b/lib/softplus.c
index b61f96b..6853f66 100644
--- a/lib/softplus.c
+++ b/lib/softplus.c
@@ -34,7 +34,12 @@ int ts_softplus(
 	for( uint_t i = 0; i < n; ++i )
 	{
 		fp_t xi = x[0][i];
-		y[0][i] = xi > 20 ? xi : log( 1 + exp( xi ) );
+		if ( xi > 20 )
+			y[0][i] = xi;
+		else if ( xi < -37 )
+			y[0][i] = exp( xi );
+		else
+			y[0][i] = log( 1 + exp( xi ) );
 	}
 	return 0;
 }
diff --git a/lib/standard_error.c b/lib/standard_error.c
index 9b0ac3b..e090deb 100644
--- a/lib/standard_error.c
+++ b/lib/standard_error.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_standard_error_p = { .n_inputs = 1, .n_outputs = 1, .n_c
 uint_t ts_standard_error_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_standard_error_params_t *)c)->k > 0 ? ((ts_standard_error_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_standard_error_params_t const *)c)->k > 0 ? ((ts_standard_error_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_standard_error(
@@ -34,7 +34,7 @@ int ts_standard_error(
 {
 	TS_PROLOGUE( ts_standard_error_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_standard_error_params_t *)c)->k;
+    uint_t k = ((ts_standard_error_params_t const *)c)->k;
     if (k < 2) return -1;
 
     for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/starc_bands.c b/lib/starc_bands.c
index 0c545f8..4975952 100644
--- a/lib/starc_bands.c
+++ b/lib/starc_bands.c
@@ -26,7 +26,7 @@ ts_parameter_t const ts_starc_bands_p = { .n_inputs = 4, .n_outputs = 3, .n_cons
 uint_t ts_starc_bands_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_starc_bands_params_t *)c)->k : 0 );
+	return ( c ? ((ts_starc_bands_params_t const *)c)->k : 0 );
 }
 
 int ts_starc_bands(
@@ -37,11 +37,20 @@ int ts_starc_bands(
 {
 	TS_PROLOGUE( ts_starc_bands_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_starc_bands_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_starc_bands_params_t const *)c)->k;
 	if (k == 0) return -1;
 	if (n < k + 1) return -1;
 
-	fp_t mult = ((ts_starc_bands_params_t *)c)->mult;
+	fp_t mult = ((ts_starc_bands_params_t const *)c)->mult;
+	if (mult < 0 || isnan(mult) || isinf(mult)) return -1;
+
+	for( uint_t i = 0; i < k; ++i )
+	{
+		y[0][i] = NAN;
+		y[1][i] = NAN;
+		y[2][i] = NAN;
+	}
 
 	for( uint_t i = k; i < n; ++i )
 	{
diff --git a/lib/starc_lower.c b/lib/starc_lower.c
index 97ac02f..16c5084 100644
--- a/lib/starc_lower.c
+++ b/lib/starc_lower.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_starc_lower_p = { .n_inputs = 4, .n_outputs = 1, .n_cons
 uint_t ts_starc_lower_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_starc_lower_params_t *)c)->k > 0 ? ((ts_starc_lower_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_starc_lower_params_t const *)c)->k > 0 ? ((ts_starc_lower_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_starc_lower(
@@ -35,9 +35,11 @@ int ts_starc_lower(
 {
 	TS_PROLOGUE( ts_starc_lower_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_starc_lower_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+	uint_t k = ((ts_starc_lower_params_t const *)c)->k;
 	if( k == 0 ) return -1;
-	fp_t mult = ((ts_starc_lower_params_t *)c)->mult;
+	fp_t mult = ((ts_starc_lower_params_t const *)c)->mult;
+	if (mult < 0 || isnan(mult) || isinf(mult)) return -1;
 
  uint_t half_k = k / 2;
     if (n <= half_k) return -1;
diff --git a/lib/starc_upper.c b/lib/starc_upper.c
index bcccb95..ad80b07 100644
--- a/lib/starc_upper.c
+++ b/lib/starc_upper.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_starc_upper_p = { .n_inputs = 4, .n_outputs = 1, .n_cons
 uint_t ts_starc_upper_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_starc_upper_params_t *)c)->k : 0 );
+	return ( c ? ((ts_starc_upper_params_t const *)c)->k : 0 );
 }
 
 int ts_starc_upper(
@@ -35,8 +35,8 @@ int ts_starc_upper(
 {
 	TS_PROLOGUE( ts_starc_upper_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_starc_upper_params_t *)c)->k;
-    fp_t mult = ((ts_starc_upper_params_t *)c)->mult;
+    uint_t k = ((ts_starc_upper_params_t const *)c)->k;
+    fp_t mult = ((ts_starc_upper_params_t const *)c)->mult;
     if ( k == 0 || k >= n ) return -1;
 
     for ( uint_t i = k; i < n; ++i )
diff --git a/lib/std_error.c b/lib/std_error.c
index f55d34e..ebcab35 100644
--- a/lib/std_error.c
+++ b/lib/std_error.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_std_error_p = { .n_inputs = 1, .n_outputs = 1, .n_consta
 uint_t ts_std_error_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_std_error_params_t *)c)->k > 0 ? ((ts_std_error_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_std_error_params_t const *)c)->k > 0 ? ((ts_std_error_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_std_error(
@@ -34,7 +34,7 @@ int ts_std_error(
 {
 	TS_PROLOGUE( ts_std_error_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_std_error_params_t *)c)->k;
+	uint_t k = ((ts_std_error_params_t const *)c)->k;
 	if ( k == 0 ) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/stoch_rsi.c b/lib/stoch_rsi.c
index 81992a6..97427be 100644
--- a/lib/stoch_rsi.c
+++ b/lib/stoch_rsi.c
@@ -25,7 +25,7 @@ ts_parameter_t const ts_stoch_rsi_p = { .n_inputs = 1, .n_outputs = 2, .n_consta
 uint_t ts_stoch_rsi_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_stoch_rsi_params_t *)c)->rsi_period + ((ts_stoch_rsi_params_t *)c)->stoch_period - 1 : 0 );
+	return ( c ? ((ts_stoch_rsi_params_t const *)c)->rsi_period + ((ts_stoch_rsi_params_t const *)c)->stoch_period - 1 : 0 );
 }
 
 int ts_stoch_rsi(
@@ -36,8 +36,8 @@ int ts_stoch_rsi(
 {
 	TS_PROLOGUE( ts_stoch_rsi_p );
 	if ( !c ) return -1;
-	uint_t rsi_period = ((ts_stoch_rsi_params_t *)c)->rsi_period;
-	uint_t stoch_period = ((ts_stoch_rsi_params_t *)c)->stoch_period;
+	uint_t rsi_period = ((ts_stoch_rsi_params_t const *)c)->rsi_period;
+	uint_t stoch_period = ((ts_stoch_rsi_params_t const *)c)->stoch_period;
 	if (rsi_period == 0 || stoch_period == 0) return -1;
 
 	fp_t *rsi_values = NULL;
diff --git a/lib/stochastic_fast.c b/lib/stochastic_fast.c
index eb203c8..d9340ad 100644
--- a/lib/stochastic_fast.c
+++ b/lib/stochastic_fast.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_stochastic_fast_p = { .n_inputs = 4, .n_outputs = 2, .n_
 uint_t ts_stochastic_fast_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_stochastic_fast_params_t *)c)->k > 0 ? 2 * ((ts_stochastic_fast_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_stochastic_fast_params_t const *)c)->k > 0 ? 2 * ((ts_stochastic_fast_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_stochastic_fast(
@@ -34,7 +34,7 @@ int ts_stochastic_fast(
 	TS_PROLOGUE( ts_stochastic_fast_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_stochastic_fast_params_t *)c)->k;
+	uint_t k = ((ts_stochastic_fast_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	// Initial window max/min
diff --git a/lib/stochastic_momentum_index.c b/lib/stochastic_momentum_index.c
index 5491c30..35af230 100644
--- a/lib/stochastic_momentum_index.c
+++ b/lib/stochastic_momentum_index.c
@@ -26,7 +26,7 @@ ts_parameter_t const ts_stochastic_momentum_index_p = { .n_inputs = 4, .n_output
 uint_t ts_stochastic_momentum_index_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_stochastic_momentum_index_params_t *)c)->k1 + ((ts_stochastic_momentum_index_params_t *)c)->k2 : 0 );
+	return ( c ? ((ts_stochastic_momentum_index_params_t const *)c)->k1 + ((ts_stochastic_momentum_index_params_t const *)c)->k2 : 0 );
 }
 
 int ts_stochastic_momentum_index(
@@ -37,9 +37,9 @@ int ts_stochastic_momentum_index(
 {
 	TS_PROLOGUE( ts_stochastic_momentum_index_p );
 	if ( !c ) return -1;
-    uint_t k1 = ((ts_stochastic_momentum_index_params_t *)c)->k1;
-    uint_t k2 = ((ts_stochastic_momentum_index_params_t *)c)->k2;
-    uint_t signal_period = ((ts_stochastic_momentum_index_params_t *)c)->signal_period;
+    uint_t k1 = ((ts_stochastic_momentum_index_params_t const *)c)->k1;
+    uint_t k2 = ((ts_stochastic_momentum_index_params_t const *)c)->k2;
+    uint_t signal_period = ((ts_stochastic_momentum_index_params_t const *)c)->signal_period;
     if (k1 == 0 || k2 == 0) return -1;
 
     fp_t *midpoint = calloc(n, sizeof(fp_t));
diff --git a/lib/stochastic_slow.c b/lib/stochastic_slow.c
index 0f84e1a..35f8b47 100644
--- a/lib/stochastic_slow.c
+++ b/lib/stochastic_slow.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_stochastic_slow_p = { .n_inputs = 4, .n_outputs = 2, .n_
 uint_t ts_stochastic_slow_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_stochastic_slow_params_t *)c)->k > 0 ? 3 * ((ts_stochastic_slow_params_t *)c)->k - 3 : 0 : 0 );
+	return ( c ? ((ts_stochastic_slow_params_t const *)c)->k > 0 ? 3 * ((ts_stochastic_slow_params_t const *)c)->k - 3 : 0 : 0 );
 }
 
 int ts_stochastic_slow(
@@ -35,7 +35,7 @@ int ts_stochastic_slow(
 	TS_PROLOGUE( ts_stochastic_slow_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_stochastic_slow_params_t *)c)->k;
+	uint_t k = ((ts_stochastic_slow_params_t const *)c)->k;
 	if (k == 0) return -1;
 
 	fp_t *fast_k = calloc( k, sizeof( fp_t ) );
diff --git a/lib/student_t_pdf.c b/lib/student_t_pdf.c
index 67c9f1d..ad8f256 100644
--- a/lib/student_t_pdf.c
+++ b/lib/student_t_pdf.c
@@ -34,7 +34,7 @@ int ts_student_t_pdf(
 {
 	TS_PROLOGUE( ts_student_t_pdf_p );
 	if ( !c ) return -1;
-	fp_t nu = ((ts_student_t_pdf_params_t *)c)->nu;
+	fp_t nu = ((ts_student_t_pdf_params_t const *)c)->nu;
 	if ( nu <= 0 )
 	{
 		for( uint_t i = 0; i < n; ++i ) y[0][i] = 0;
diff --git a/lib/summation.c b/lib/summation.c
index 6d0020b..01d6735 100755
--- a/lib/summation.c
+++ b/lib/summation.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_summation_p = { .n_inputs = 1, .n_outputs = 1, .n_consta
 uint_t ts_summation_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_summation_params_t *)c)->k > 0 ? ((ts_summation_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_summation_params_t const *)c)->k > 0 ? ((ts_summation_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_summation(
@@ -35,7 +35,7 @@ int ts_summation(
 {
 	TS_PROLOGUE( ts_summation_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_summation_params_t *)c)->k;
+	uint_t k = ((ts_summation_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 	
 	uint_t xi = 0;
diff --git a/lib/supertrend.c b/lib/supertrend.c
index 4487e96..c062805 100644
--- a/lib/supertrend.c
+++ b/lib/supertrend.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_supertrend_p = { .n_inputs = 4, .n_outputs = 2, .n_const
 uint_t ts_supertrend_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_supertrend_params_t *)c)->k : 0 );
+	return ( c ? ((ts_supertrend_params_t const *)c)->k : 0 );
 }
 
 int ts_supertrend(
@@ -36,8 +36,8 @@ int ts_supertrend(
 	TS_PROLOGUE( ts_supertrend_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_supertrend_params_t *)c)->k;
-	fp_t mult = ((ts_supertrend_params_t *)c)->mult;
+	uint_t k = ((ts_supertrend_params_t const *)c)->k;
+	fp_t mult = ((ts_supertrend_params_t const *)c)->mult;
 	if (k == 0 || n <= k) return -1;
 
 	fp_t tr = ts_h( x, 1 ) - ts_l( x, 1 );
diff --git a/lib/swish.c b/lib/swish.c
index 7d09787..ae0105f 100644
--- a/lib/swish.c
+++ b/lib/swish.c
@@ -34,7 +34,12 @@ int ts_swish(
 	for( uint_t i = 0; i < n; ++i )
 	{
 		fp_t xi = x[0][i];
-		y[0][i] = xi / ( 1 + exp( -xi ) );
+		if ( xi > 20 )
+			y[0][i] = xi;
+		else if ( xi < -20 )
+			y[0][i] = xi * exp( xi );
+		else
+			y[0][i] = xi / ( 1 + exp( -xi ) );
 	}
 	return 0;
 }
diff --git a/lib/synthetic_yield.c b/lib/synthetic_yield.c
index c2c8d62..fecde51 100644
--- a/lib/synthetic_yield.c
+++ b/lib/synthetic_yield.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_synthetic_yield_p = { .n_inputs = 1, .n_outputs = 1, .n_
 uint_t ts_synthetic_yield_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_synthetic_yield_params_t *)c)->k : 0 );
+	return ( c ? ((ts_synthetic_yield_params_t const *)c)->k : 0 );
 }
 
 int ts_synthetic_yield(
@@ -34,9 +34,10 @@ int ts_synthetic_yield(
 {
 	TS_PROLOGUE( ts_synthetic_yield_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_synthetic_yield_params_t *)c)->k;
+	uint_t k = ((ts_synthetic_yield_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
+	for( uint_t i = 0; i < k; ++i ) y[0][i] = 0;
 	for( uint_t i = k; i < n; ++i )
 	{
 		if( x[0][i - k] == 0 ) { y[0][i] = 0; continue; }
diff --git a/lib/t3.c b/lib/t3.c
index 4689d54..34aff86 100644
--- a/lib/t3.c
+++ b/lib/t3.c
@@ -29,7 +29,6 @@ int ts_t3(
 {
 	TS_PROLOGUE( ts_t3_p );
 	(void)c;
-	if (n == 0) return -1;
 
 	uint_t k = 5;
 
diff --git a/lib/test.c b/lib/test.c
index 56c47eb..d022f6e 100755
--- a/lib/test.c
+++ b/lib/test.c
@@ -33,42 +33,55 @@ void ts_test_all( void )
 }
 
 bool ts_test(
-	void ( *ts_function )(
-        fp_t * const *y, 
-	    fp_t const * const *x, 
-		uint_t n, 
-		ts_constant_t const *c 
+	int ( *ts_function )(
+        fp_t * const *y,
+	    uint_t y_n,
+	    fp_t const * const *x,
+	    uint_t x_n,
+		uint_t n,
+		ts_constant_t const *c
     ),
-    uint_t ( *ts_offset )( 
-        ts_constant_t const *c 
+    uint_t ( *ts_offset )(
+        ts_constant_t const *c
     ),
 	fp_t const * const *x,
 	fp_t const * const *e,
 	uint_t n,
 	ts_constant_t const *c,
     ts_parameter_t const *m )
-{                                                                       
+{
+	if ( !ts_function || !ts_offset || !m || !e || !x ) return false;
+
 	uint_t offset = ts_offset( c );
-	uint_t y_n = n - offset;
+	if ( offset >= n ) return false;
+	uint_t y_len = n - offset;
     bool result = true;
-                                                               
-	fp_t *y[m->y];
 
-    for( uint_t i = 0; i < m->y; i++ )
+	fp_t *y[m->n_outputs];
+
+    for( uint_t i = 0; i < m->n_outputs; i++ )
     {
-        fp_t *tmp = malloc( y_n * sizeof( fp_t ) );
+        fp_t *tmp = calloc( y_len, sizeof( fp_t ) );
+        if ( !tmp )
+        {
+            for ( uint_t j = 0; j < i; j++ ) free( y[j] );
+            return false;
+        }
         y[i] = tmp;
     }
 
-	ts_function( y, x, n, c );                       
+	if ( ts_function( y, m->n_outputs, x, m->n_inputs, n, c ) != 0 )
+	{
+		for ( uint_t i = 0; i < m->n_outputs; i++ ) free( y[i] );
+		return false;
+	}
 
-    for( uint_t i = 0; i < m->y; ++i )
+    for( uint_t i = 0; i < m->n_outputs; ++i )
     {
-    	for( uint_t j = 0; j < y_n; ++j )                                     
+    	for( uint_t j = 0; j < y_len; ++j )
 	    {
-		    // _ts_assert_approximate( y[i][j], e[i][j], TS_TEST_EPSILON ); 
-		    result &= _ts_is_approximate( y[i][j], e[i][j], TS_TEST_EPSILON ); 
-	    }                                                                     
+		    result &= _ts_is_approximate( y[i][j], e[i][j], TS_TEST_EPSILON );
+	    }
 
         free( y[i] );
     }
diff --git a/lib/trade_volume_index.c b/lib/trade_volume_index.c
index 2e1b50d..a123379 100644
--- a/lib/trade_volume_index.c
+++ b/lib/trade_volume_index.c
@@ -24,20 +24,20 @@ uint_t ts_trade_volume_index_offset( ts_constant_t const *c )
 }
 
 int ts_trade_volume_index(
-		fp_t * const *y, uint_t y_n,
-		fp_t const * const *x, uint_t x_n,
-		uint_t n, ts_constant_t const *c
-	)
-	{
-		TS_PROLOGUE( ts_trade_volume_index_p );
- (void)c;
+	fp_t * const *y, uint_t y_n,
+	fp_t const * const *x, uint_t x_n,
+	uint_t n, ts_constant_t const *c
+)
+{
+	TS_PROLOGUE( ts_trade_volume_index_p );
+	(void)c;
 	if (n < 2) return -1;
 	for( uint_t i = 0; i + 1 < n; ++i )
-		{
-			fp_t roc = x[3][i] != 0 ? ( x[3][i + 1] - x[3][i] ) / x[3][i] : 0;
-			y[0][i] = ( i == 0 ? 0 : y[0][i - 1] ) + roc * x[4][i + 1];
-		}
-		y[0][n - 1] = y[0][n - 2];
-		return 0;
+	{
+		fp_t roc = x[3][i] != 0 ? ( x[3][i + 1] - x[3][i] ) / x[3][i] : 0;
+		y[0][i] = ( i == 0 ? 0 : y[0][i - 1] ) + roc * x[4][i + 1];
 	}
+	y[0][n - 1] = y[0][n - 2];
+	return 0;
+}
 
diff --git a/lib/trend_intensity_index.c b/lib/trend_intensity_index.c
index 451e440..2f8a628 100644
--- a/lib/trend_intensity_index.c
+++ b/lib/trend_intensity_index.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_trend_intensity_index_p = { .n_inputs = 5, .n_outputs =
 uint_t ts_trend_intensity_index_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_trend_intensity_index_params_t *)c)->k > 0 ? ((ts_trend_intensity_index_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_trend_intensity_index_params_t const *)c)->k > 0 ? ((ts_trend_intensity_index_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_trend_intensity_index(
@@ -33,7 +33,7 @@ int ts_trend_intensity_index(
 {
 	TS_PROLOGUE( ts_trend_intensity_index_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_trend_intensity_index_params_t *)c)->k;
+    uint_t k = ((ts_trend_intensity_index_params_t const *)c)->k;
     if ( k == 0 || n < k ) return -1;
 
     fp_t signed_sum = 0;
diff --git a/lib/trix.c b/lib/trix.c
index a9aac88..ee5ed71 100755
--- a/lib/trix.c
+++ b/lib/trix.c
@@ -31,9 +31,8 @@ int ts_trix(
 {
 	TS_PROLOGUE( ts_trix_p );
 	if ( !c ) return -1;
-	if (n == 0) return -1;
 
-	fp_t a = ((ts_trix_params_t *)c)->a;
+	fp_t a = ((ts_trix_params_t const *)c)->a;
 	if (a == 0) return -1;
 
 	fp_t ema1 = x[0][0];
diff --git a/lib/ts.c b/lib/ts.c
index 68e2f41..e035625 100755
--- a/lib/ts.c
+++ b/lib/ts.c
@@ -7,18 +7,19 @@
 
 fp_t * ts_fill( fp_t *x, uint_t n, fp_t x0, fp_t x1 )
 {
-	fp_t step = ( x1 - x0 ) / ( n - 1 );
+	if ( !x || n == 0 ) return x;
 
-	if( x0 == 0.0 && x1 == 0.0 )
+	fp_t step = n > 1 ? ( x1 - x0 ) / ( fp_t )( n - 1 ) : 0.0;
+
+	if( fabs( x0 ) < TS_FILL_ZERO_THRESHOLD && fabs( x1 ) < TS_FILL_ZERO_THRESHOLD )
 	{
-		memset(x, 0, sizeof( fp_t ) * n );
+		memset( x, 0, sizeof( fp_t ) * n );
 	}
-
 	else
 	{
 		for( uint_t i = 0; i < n; i++ )
 		{
-			x[i] = x0 + ( i * step );
+			x[i] = x0 + ( (fp_t)i * step );
 		}
 	}
 
@@ -26,42 +27,48 @@ fp_t * ts_fill( fp_t *x, uint_t n, fp_t x0, fp_t x1 )
 }
 
 
-void ts_print( fp_t *x, uint_t n )
+void ts_print( fp_t const *x, uint_t n, FILE *stream )
 {
-    fputc('[', stdout);
+	if ( !x || n == 0 ) return;
+
+	FILE *out = stream ? stream : stdout;
 
-    uint_t i;
-    for( i = 0; i < n - 1; i++ )
-    {
-        fprintf(stdout, "%f,", x[i]);
-    }
+	fputc( '[', out );
+
+	for ( uint_t i = 0; i < n - 1; i++ )
+	{
+		fprintf( out, "%f,", x[i] );
+	}
 
-    fprintf(stdout, "%f]", x[i]);
+	fprintf( out, "%f]", x[n - 1] );
 }
 
 
-void ts_pretty_print( fp_t const * const *x, uint_t m, uint_t n )
+void ts_pretty_print( fp_t const * const *x, uint_t m, uint_t n, FILE *stream )
 {
-    if( m > 1 )
-    {
-        for( uint_t i = 0; i < n; i++ )
-        {
-            uint_t j = 0;
-            for( ; j < m; j++ )
-            {
-                fprintf( stdout, "%f  ", x[i][j] );
-            }
+	if ( !x || m == 0 || n == 0 ) return;
 
-            fputs( "\n", stdout );
-        }
-    }
-    else
-    {
-        for( uint_t i = 0; i < n; i++ )
-        {
-            fprintf( stdout, "%f\n", x[0][i] );
-        }
-    }
+	FILE *out = stream ? stream : stdout;
+
+	if( m > 1 )
+	{
+		for( uint_t i = 0; i < n; i++ )
+		{
+			for( uint_t j = 0; j < m; j++ )
+			{
+				fprintf( out, "%f  ", x[j][i] );
+			}
+
+			fputs( "\n", out );
+		}
+	}
+	else
+	{
+		for( uint_t i = 0; i < n; i++ )
+		{
+			fprintf( out, "%f\n", x[0][i] );
+		}
+	}
 }
 
 
@@ -91,29 +98,19 @@ fp_t _ts_triangle_number( fp_t x )
 
 fp_t _ts_sum_to_covariance( fp_t sum_xy, fp_t sum_x, fp_t sum_y, uint_t k )
 {
+    if ( k == 0 ) return 0.0;
     return ( sum_xy - ( sum_x * sum_y / k ) ) / k;
 }
 
 
 fp_t _ts_sum_to_variance( fp_t sum_x2, fp_t sum_x, uint_t k )
 {
-    return _ts_sum_to_covariance( sum_x2, sum_x, sum_x, k );
+    return fmax( 0.0, _ts_sum_to_covariance( sum_x2, sum_x, sum_x, k ) );
 }
 
 
 uint_t _ts_circle_increment( uint_t i, uint_t k )
 {
+    if ( k == 0 ) return i;
     return ( i + 1 ) % k;
-}
-
-
-// ts_constant_t * ts_constant_init( uint_t n, ... )
-// {
-//     va_list args;
-//     va_start( args, n );
-
-//     for( uint_t i = 0; i < n; i++ )
-//     {
-
-//     }
-// }
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/lib/ulcer_index.c b/lib/ulcer_index.c
index ca70734..1063880 100644
--- a/lib/ulcer_index.c
+++ b/lib/ulcer_index.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_ulcer_index_p = { .n_inputs = 1, .n_outputs = 1, .n_cons
 uint_t ts_ulcer_index_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_ulcer_index_params_t *)c)->k > 0 ? ((ts_ulcer_index_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_ulcer_index_params_t const *)c)->k > 0 ? ((ts_ulcer_index_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_ulcer_index(
@@ -35,8 +35,8 @@ int ts_ulcer_index(
 {
 	TS_PROLOGUE( ts_ulcer_index_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_ulcer_index_params_t *)c)->k;
-	if (k == 0 || n < k) return -1;
+	uint_t k = ((ts_ulcer_index_params_t const *)c)->k;
+	if (k == 0) return -1;
 
 	/* Precompute cumulative highest-high for each index: O(n) */
 	fp_t *cum_hhv = calloc( n, sizeof( fp_t ) );
@@ -50,13 +50,13 @@ int ts_ulcer_index(
 		}
 	}
 
- for( uint_t i = k - 1; i < n; ++i )
+	for( uint_t i = k - 1; i < n; ++i )
 	{
 		fp_t hhv = x[0][i - k + 1];
 		for( uint_t j = 1; j < k; ++j )
 		{
 			fp_t v = x[0][i - k + 1 + j];
-			if (v > hhv) hhv = v;
+			if ( v > hhv ) hhv = v;
 		}
 
 		fp_t d_sq_sum = 0;
diff --git a/lib/valuation_lines.c b/lib/valuation_lines.c
index b56a871..cba9b2e 100644
--- a/lib/valuation_lines.c
+++ b/lib/valuation_lines.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_valuation_lines_p = { .n_inputs = 4, .n_outputs = 2, .n_
 uint_t ts_valuation_lines_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_valuation_lines_params_t *)c)->k > 0 ? ((ts_valuation_lines_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_valuation_lines_params_t const *)c)->k > 0 ? ((ts_valuation_lines_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_valuation_lines(
@@ -34,7 +34,7 @@ int ts_valuation_lines(
 {
 	TS_PROLOGUE( ts_valuation_lines_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_valuation_lines_params_t *)c)->k;
+	uint_t k = ((ts_valuation_lines_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k - 1; i < n; ++i )
diff --git a/lib/variable_index_dynamic_average.c b/lib/variable_index_dynamic_average.c
index 5f4ae4f..0e78d13 100644
--- a/lib/variable_index_dynamic_average.c
+++ b/lib/variable_index_dynamic_average.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_variable_index_dynamic_average_p = { .n_inputs = 1, .n_o
 uint_t ts_variable_index_dynamic_average_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_variable_index_dynamic_average_params_t *)c)->period : 0 );
+	return ( c ? ((ts_variable_index_dynamic_average_params_t const *)c)->period : 0 );
 }
 
 int ts_variable_index_dynamic_average(
@@ -34,7 +34,7 @@ int ts_variable_index_dynamic_average(
 {
 	TS_PROLOGUE( ts_variable_index_dynamic_average_p );
 	if ( !c ) return -1;
-    uint_t period = ((ts_variable_index_dynamic_average_params_t *)c)->period;
+    uint_t period = ((ts_variable_index_dynamic_average_params_t const *)c)->period;
     if (period < 2 || n <= period) return -1;
 
     fp_t vidya = x[0][period];
diff --git a/lib/variance.c b/lib/variance.c
index f307198..e288233 100755
--- a/lib/variance.c
+++ b/lib/variance.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_variance_p = { .n_inputs = 1, .n_outputs = 1, .n_constan
 uint_t ts_variance_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_variance_params_t *)c)->k > 0 ? ((ts_variance_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_variance_params_t const *)c)->k > 0 ? ((ts_variance_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_variance(
@@ -34,7 +34,7 @@ int ts_variance(
 	TS_PROLOGUE( ts_variance_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_variance_params_t *)c)->k;
+	uint_t k = ((ts_variance_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	uint_t xi = 0;
diff --git a/lib/variance_exponential.c b/lib/variance_exponential.c
index 338a140..0700aee 100755
--- a/lib/variance_exponential.c
+++ b/lib/variance_exponential.c
@@ -30,9 +30,8 @@ int ts_variance_exponential(
 {
 	TS_PROLOGUE( ts_variance_exponential_p );
 	if ( !c ) return -1;
-	if (n == 0) return -1;
 
-	fp_t a = ((ts_variance_exponential_params_t *)c)->a;
+	fp_t a = ((ts_variance_exponential_params_t const *)c)->a;
 	if (a == 0) return -1;
 
 	y[0][0] = 0;
diff --git a/lib/vertical_horizontal_filter.c b/lib/vertical_horizontal_filter.c
index f5c91cf..e032dbd 100644
--- a/lib/vertical_horizontal_filter.c
+++ b/lib/vertical_horizontal_filter.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_vertical_horizontal_filter_p = { .n_inputs = 4, .n_outpu
 uint_t ts_vertical_horizontal_filter_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_vertical_horizontal_filter_params_t *)c)->k : 0 );
+	return ( c ? ((ts_vertical_horizontal_filter_params_t const *)c)->k : 0 );
 }
 
 int ts_vertical_horizontal_filter(
@@ -34,7 +34,7 @@ int ts_vertical_horizontal_filter(
 {
 	TS_PROLOGUE( ts_vertical_horizontal_filter_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_vertical_horizontal_filter_params_t *)c)->k;
+    uint_t k = ((ts_vertical_horizontal_filter_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t cum_den = 0;
diff --git a/lib/volatility_stop.c b/lib/volatility_stop.c
index bfb207b..6055144 100644
--- a/lib/volatility_stop.c
+++ b/lib/volatility_stop.c
@@ -24,7 +24,7 @@ ts_parameter_t const ts_volatility_stop_p = { .n_inputs = 4, .n_outputs = 2, .n_
 uint_t ts_volatility_stop_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_volatility_stop_params_t *)c)->k : 0 );
+	return ( c ? ((ts_volatility_stop_params_t const *)c)->k : 0 );
 }
 
 int ts_volatility_stop(
@@ -35,9 +35,17 @@ int ts_volatility_stop(
 {
 	TS_PROLOGUE( ts_volatility_stop_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_volatility_stop_params_t *)c)->k;
-    fp_t mult = ((ts_volatility_stop_params_t *)c)->mult;
+	TS_CHECK_INPUT(x, x_n, n);
+    uint_t k = ((ts_volatility_stop_params_t const *)c)->k;
+    fp_t mult = ((ts_volatility_stop_params_t const *)c)->mult;
     if (k == 0 || n < k) return -1;
+    if (mult < 0 || isnan(mult) || isinf(mult)) return -1;
+
+    for( uint_t i = 0; i < k; ++i )
+    {
+        y[0][i] = NAN;
+        y[1][i] = NAN;
+    }
 
     for( uint_t i = k; i < n; ++i )
     {
diff --git a/lib/volatility_system.c b/lib/volatility_system.c
index dbb74d1..b8e0c33 100644
--- a/lib/volatility_system.c
+++ b/lib/volatility_system.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_volatility_system_p = { .n_inputs = 4, .n_outputs = 1, .
 uint_t ts_volatility_system_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? 2 * ((ts_volatility_system_params_t *)c)->k : 0 );
+	return ( c ? 2 * ((ts_volatility_system_params_t const *)c)->k : 0 );
 }
 
 int ts_volatility_system(
@@ -34,12 +34,16 @@ int ts_volatility_system(
 {
 	TS_PROLOGUE( ts_volatility_system_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_volatility_system_params_t *)c)->k;
+	TS_CHECK_INPUT(x, x_n, n);
+    uint_t k = ((ts_volatility_system_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     uint_t range_period = 2 * k;
     if (n < range_period) return -1;
 
+    for ( uint_t i = 0; i < range_period; ++i )
+        y[0][i] = NAN;
+
     fp_t ema = (ts_c(x, range_period - 2) + ts_c(x, range_period - 1)) / 2.0;
 
     for( uint_t i = range_period; i < n; ++i )
diff --git a/lib/volume_moving_average.c b/lib/volume_moving_average.c
index 93eb592..33f263c 100644
--- a/lib/volume_moving_average.c
+++ b/lib/volume_moving_average.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_volume_moving_average_p = { .n_inputs = 5, .n_outputs =
 uint_t ts_volume_moving_average_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_volume_moving_average_params_t *)c)->k > 0 ? ((ts_volume_moving_average_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_volume_moving_average_params_t const *)c)->k > 0 ? ((ts_volume_moving_average_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_volume_moving_average(
@@ -33,7 +33,7 @@ int ts_volume_moving_average(
 {
 	TS_PROLOGUE( ts_volume_moving_average_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_volume_moving_average_params_t *)c)->k;
+    uint_t k = ((ts_volume_moving_average_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for (uint_t i = k - 1; i < n; ++i)
diff --git a/lib/volume_oscillator.c b/lib/volume_oscillator.c
index 6aa59f0..37d34c4 100644
--- a/lib/volume_oscillator.c
+++ b/lib/volume_oscillator.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_volume_oscillator_p = { .n_inputs = 1, .n_outputs = 1, .
 uint_t ts_volume_oscillator_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_volume_oscillator_params_t *)c)->slow_k > 0 ? (uint_t)(((ts_volume_oscillator_params_t *)c)->slow_k - 1) : 0 : 0 );
+	return ( c ? ((ts_volume_oscillator_params_t const *)c)->slow_k > 0 ? (uint_t)(((ts_volume_oscillator_params_t const *)c)->slow_k - 1) : 0 : 0 );
 }
 
 int ts_volume_oscillator(
@@ -34,10 +34,9 @@ int ts_volume_oscillator(
 {
 	TS_PROLOGUE( ts_volume_oscillator_p );
 	if ( !c ) return -1;
-    fp_t fast_k = ((ts_volume_oscillator_params_t *)c)->fast_k;
-    fp_t slow_k = ((ts_volume_oscillator_params_t *)c)->slow_k;
+    fp_t fast_k = ((ts_volume_oscillator_params_t const *)c)->fast_k;
+    fp_t slow_k = ((ts_volume_oscillator_params_t const *)c)->slow_k;
     if (fast_k == 0 || slow_k == 0) return -1;
-    if (n == 0) return -1;
 
     fp_t fast_a = 2.0 / (fast_k + 1);
     fp_t slow_a = 2.0 / (slow_k + 1);
diff --git a/lib/volume_rate_of_change.c b/lib/volume_rate_of_change.c
index ae9c776..b9d09c8 100644
--- a/lib/volume_rate_of_change.c
+++ b/lib/volume_rate_of_change.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_volume_rate_of_change_p = { .n_inputs = 5, .n_outputs =
 uint_t ts_volume_rate_of_change_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_volume_rate_of_change_params_t *)c)->k : 0 );
+	return ( c ? ((ts_volume_rate_of_change_params_t const *)c)->k : 0 );
 }
 
 int ts_volume_rate_of_change(
@@ -34,7 +34,7 @@ int ts_volume_rate_of_change(
 {
 	TS_PROLOGUE( ts_volume_rate_of_change_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_volume_rate_of_change_params_t *)c)->k;
+    uint_t k = ((ts_volume_rate_of_change_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     for (uint_t i = k; i < n; ++i)
diff --git a/lib/volume_weighted_moving_average.c b/lib/volume_weighted_moving_average.c
index d6cd6bd..a7dc781 100644
--- a/lib/volume_weighted_moving_average.c
+++ b/lib/volume_weighted_moving_average.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_volume_weighted_moving_average_p = { .n_inputs = 5, .n_o
 uint_t ts_volume_weighted_moving_average_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_volume_weighted_moving_average_params_t *)c)->k > 0 ? ((ts_volume_weighted_moving_average_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_volume_weighted_moving_average_params_t const *)c)->k > 0 ? ((ts_volume_weighted_moving_average_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_volume_weighted_moving_average(
@@ -33,7 +33,7 @@ int ts_volume_weighted_moving_average(
 {
 	TS_PROLOGUE( ts_volume_weighted_moving_average_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_volume_weighted_moving_average_params_t *)c)->k;
+    uint_t k = ((ts_volume_weighted_moving_average_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     fp_t cv_sum = 0;
diff --git a/lib/vortex_indicator.c b/lib/vortex_indicator.c
index 39ecfbc..6e80974 100644
--- a/lib/vortex_indicator.c
+++ b/lib/vortex_indicator.c
@@ -23,7 +23,7 @@ ts_parameter_t const ts_vortex_indicator_p = { .n_inputs = 4, .n_outputs = 2, .n
 uint_t ts_vortex_indicator_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_vortex_indicator_params_t *)c)->k : 0 );
+	return ( c ? ((ts_vortex_indicator_params_t const *)c)->k : 0 );
 }
 
 int ts_vortex_indicator(
@@ -34,7 +34,7 @@ int ts_vortex_indicator(
 {
 	TS_PROLOGUE( ts_vortex_indicator_p );
 	if ( !c ) return -1;
-	uint_t k = ((ts_vortex_indicator_params_t *)c)->k;
+	uint_t k = ((ts_vortex_indicator_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	for( uint_t i = k; i < n; ++i )
diff --git a/lib/vwap_period.c b/lib/vwap_period.c
index b8af2bd..58873ed 100644
--- a/lib/vwap_period.c
+++ b/lib/vwap_period.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_vwap_period_p = { .n_inputs = 5, .n_outputs = 1, .n_cons
 uint_t ts_vwap_period_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_vwap_period_params_t *)c)->k > 0 ? ((ts_vwap_period_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_vwap_period_params_t const *)c)->k > 0 ? ((ts_vwap_period_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_vwap_period(
@@ -33,7 +33,7 @@ int ts_vwap_period(
 {
 	TS_PROLOGUE( ts_vwap_period_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_vwap_period_params_t *)c)->k;
+    uint_t k = ((ts_vwap_period_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     /* Periodic VWAP: reset cumulative sums every k bars */
diff --git a/lib/weibull_pdf.c b/lib/weibull_pdf.c
index 894c94a..ddfd77d 100644
--- a/lib/weibull_pdf.c
+++ b/lib/weibull_pdf.c
@@ -34,7 +34,7 @@ int ts_weibull_pdf(
 {
 	TS_PROLOGUE( ts_weibull_pdf_p );
 	if ( !c ) return -1;
-	fp_t k = ((ts_weibull_pdf_params_t *)c)->k;
+	fp_t k = ((ts_weibull_pdf_params_t const *)c)->k;
 	if (k <= 0.0 || isnan(k) || isinf(k)) return -1;
 	for( uint_t i = 0; i < n; ++i )
 	{
diff --git a/lib/wilders_smoothing.c b/lib/wilders_smoothing.c
index 7aca8ad..f6a48b2 100644
--- a/lib/wilders_smoothing.c
+++ b/lib/wilders_smoothing.c
@@ -33,9 +33,8 @@ int ts_wilders_smoothing(
 {
 	TS_PROLOGUE( ts_wilders_smoothing_p );
 	if ( !c ) return -1;
-	if (n == 0) return -1;
 
-    fp_t k = ((ts_wilders_smoothing_params_t *)c)->k;
+    fp_t k = ((ts_wilders_smoothing_params_t const *)c)->k;
 	if (k == 0) return -1;
     fp_t a = 1.0 / k;
 
diff --git a/lib/williams_r.c b/lib/williams_r.c
index f0fae3f..f755284 100644
--- a/lib/williams_r.c
+++ b/lib/williams_r.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_williams_r_p = { .n_inputs = 4, .n_outputs = 1, .n_const
 uint_t ts_williams_r_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_williams_r_params_t *)c)->k > 0 ? ((ts_williams_r_params_t *)c)->k - 1 : 0 : 0 );
+	return ( c ? ((ts_williams_r_params_t const *)c)->k > 0 ? ((ts_williams_r_params_t const *)c)->k - 1 : 0 : 0 );
 }
 
 int ts_williams_r(
@@ -34,7 +34,7 @@ int ts_williams_r(
 	TS_PROLOGUE( ts_williams_r_p );
 	if ( !c ) return -1;
 	TS_CHECK_INPUT(x, x_n, n);
-	uint_t k = ((ts_williams_r_params_t *)c)->k;
+	uint_t k = ((ts_williams_r_params_t const *)c)->k;
 	if (k == 0 || n < k) return -1;
 
 	// Initial window max/min
diff --git a/lib/zero_lag_ema.c b/lib/zero_lag_ema.c
index c78adbd..a2b27d9 100644
--- a/lib/zero_lag_ema.c
+++ b/lib/zero_lag_ema.c
@@ -22,7 +22,7 @@ ts_parameter_t const ts_zero_lag_ema_p = { .n_inputs = 1, .n_outputs = 1, .n_con
 uint_t ts_zero_lag_ema_offset( ts_constant_t const *c )
 {
 	( void )c;
-	return ( c ? ((ts_zero_lag_ema_params_t *)c)->k : 0 );
+	return ( c ? ((ts_zero_lag_ema_params_t const *)c)->k : 0 );
 }
 
 int ts_zero_lag_ema(
@@ -33,7 +33,7 @@ int ts_zero_lag_ema(
 {
 	TS_PROLOGUE( ts_zero_lag_ema_p );
 	if ( !c ) return -1;
-    uint_t k = ((ts_zero_lag_ema_params_t *)c)->k;
+    uint_t k = ((ts_zero_lag_ema_params_t const *)c)->k;
     if (k == 0 || n < k) return -1;
 
     /* Zero-lag EMA: compute lag, then apply EMA to (2*x - x_lag) */
diff --git a/lib/zigzag.c b/lib/zigzag.c
index 50549e2..db4a5f2 100644
--- a/lib/zigzag.c
+++ b/lib/zigzag.c
@@ -35,9 +35,8 @@ int ts_zigzag(
 {
 	TS_PROLOGUE( ts_zigzag_p );
 	if ( !c ) return -1;
-	if (n == 0) return -1;
 
-	fp_t threshold = ((ts_zigzag_params_t *)c)->threshold;
+	fp_t threshold = ((ts_zigzag_params_t const *)c)->threshold;
 	if (threshold <= 0 || isnan(threshold) || isinf(threshold)) return -1;
 
 	y[0][0] = x[0][0];