initial commit: ts time series analysis library v0.1.0

- 354 financial and mathematical time-series indicators
- Uniform C11 API with consistent function signatures
- 349 passing tests with -Werror
- Static and shared library builds
- pkg-config integration
- Python bindings
- Fuzzing and sanitizer support
- Security hardening flags

1 files changed, 50 insertions, 0 deletions

diff --git a/lib/atanh.c b/lib/atanh.c
new file mode 100644
index 0000000..06896df
--- /dev/null
+++ b/lib/atanh.c
@@ -0,0 +1,50 @@
+// Hyperbolic Arctangent
+//
+// atanh - inverse hyperbolic tangent
+//
+// y[t] = atanh( x[t] )       if |x[t]| < 1
+// y[t] = +INFINITY           if x[t] == 1
+// y[t] = -INFINITY           if x[t] == -1
+// y[t] = NAN                 if |x[t]| > 1
+//
+// X_n - 1
+// Y_n - 1
+// C_n - 0
+
+#include <math.h>
+#include "ts.h"
+
+
+
+ts_parameter_t const ts_atanh_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 0, .params_size = 0 };
+
+
+uint_t ts_atanh_offset( ts_constant_t const *c )
+{
+	( void )c;
+	return ( 0 );
+}
+
+int ts_atanh(
+	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_atanh_p );
+	(void)c;
+	for( uint_t i = 0; i < n; ++i )
+	{
+		fp_t v = x[0][i];
+		if ( v > -1.0 && v < 1.0 )
+			y[0][i] = atanh( v );
+		else if ( v == 1.0 )
+			y[0][i] = INFINITY;
+		else if ( v == -1.0 )
+			y[0][i] = -INFINITY;
+		else
+			y[0][i] = (fp_t)NAN;
+	}
+	return 0;
+}
+