1 files changed, 42 insertions, 0 deletions
diff --git a/lib/secant_hyperbolic.c b/lib/secant_hyperbolic.c
new file mode 100644
index 0000000..6956840
--- /dev/null
+++ b/lib/secant_hyperbolic.c
@@ -0,0 +1,42 @@
+// Hyperbolic Secant
+//
+// secant_hyperbolic - sech
+//
+// f( x ) = sech( x )
+//        = 1 / cosh( x )
+//        = 2 / ( e^x + e^( -x ) )
+//
+// X_n - 1
+// Y_n - 1
+// C_n - 0
+
+
+#include <math.h>
+#include "ts.h"
+
+
+
+ts_parameter_t const ts_secant_hyperbolic_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 0, .params_size = 0 };
+
+
+uint_t ts_secant_hyperbolic_offset( ts_constant_t const *c )
+{
+	( void )c;
+	return ( 0 );
+}
+
+int ts_secant_hyperbolic(
+	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_secant_hyperbolic_p );
+	(void)c;
+	for( uint_t i = 0; i < n; ++i )
+	{
+		y[0][i] = _ts_reciprocal( cosh( x[0][i] ) );
+	}
+	return 0;
+}
+