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// 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 const *)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;
}
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