1 files changed, 58 insertions, 0 deletions
diff --git a/lib/prime_number_bands.c b/lib/prime_number_bands.c
new file mode 100644
index 0000000..ac94e7b
--- /dev/null
+++ b/lib/prime_number_bands.c
@@ -0,0 +1,58 @@
+// Prime Number Bands
+//
+// prime_number_bands
+//
+// Prime Number Bands
+//
+// 
+//
+// Inputs:    1
+// Outputs:   3
+// Constants: 1
+
+
+#include <math.h>
+#include "ts.h"
+
+typedef struct {
+    uint_t k;
+} ts_prime_number_bands_params_t;
+
+ts_parameter_t const ts_prime_number_bands_p = { .n_inputs = 1, .n_outputs = 3, .n_constants = 1, .params_size = sizeof(ts_prime_number_bands_params_t) };
+
+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 );
+}
+
+int ts_prime_number_bands(
+	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_prime_number_bands_p );
+	if ( !c ) return -1;
+	uint_t k = ((ts_prime_number_bands_params_t *)c)->k;
+	if (k == 0 || n < k) return -1;
+
+	for( uint_t i = k - 1; i < n; ++i )
+	{
+		fp_t sum = 0, sum2 = 0;
+		for( uint_t j = 0; j < k; ++j )
+		{
+			fp_t v = x[0][i - k + 1 + j];
+			sum += v;
+			sum2 += v * v;
+		}
+		fp_t mean = sum / k;
+		fp_t variance = sum2 / k - mean * mean;
+		fp_t stddev = variance >= 0 ? sqrt( variance ) : 0;
+		y[0][i] = mean;
+		y[1][i] = mean + 2.0 * stddev;
+		y[2][i] = mean - 2.0 * stddev;
+	}
+	return 0;
+}
+