1 files changed, 71 insertions, 0 deletions
diff --git a/lib/power.c b/lib/power.c
new file mode 100755
index 0000000..41bb644
--- /dev/null
+++ b/lib/power.c
@@ -0,0 +1,71 @@
+// Power
+//
+// power - pow
+//
+// f( x ) = x^r
+//
+// X_n - 1
+// Y_n - 1
+// C_n - 1
+//
+// c[0] = r
+
+
+#include <math.h>
+#include "ts.h"
+
+
+typedef struct {
+    fp_t r;
+} ts_power_params_t;
+
+ts_parameter_t const ts_power_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 1, .params_size = sizeof(ts_power_params_t) };
+
+
+uint_t ts_power_offset( ts_constant_t const *c )
+{
+	( void )c;
+	return ( 0 );
+}
+
+int ts_power(
+	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_power_p );
+	if ( !c ) return -1;
+	fp_t r = ((ts_power_params_t *)c)->r;
+
+	for( uint_t i = 0; i < n; ++i )
+	{
+		fp_t base = x[0][i];
+		if ( base > 0 )
+		{
+			y[0][i] = pow( base, r );
+		}
+		else if ( base < 0 )
+		{
+			fp_t intpart;
+			if ( modf( r, &intpart ) == 0 )
+			{
+				fp_t result = pow( -base, r );
+				long ip = (long)intpart;
+				y[0][i] = (ip >= 0 && (ip & 1) != 0) ? -result : result;
+			}
+			else
+			{
+				y[0][i] = 0;
+			}
+		}
+		else
+		{
+			if (r > 0.0) y[0][i] = 0.0;
+			else if (r < 0.0) y[0][i] = INFINITY;
+			else y[0][i] = 1.0;
+		}
+	}
+	return 0;
+}
+