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// Hermite
//
// hermite
//
// Hermite polynomial
//
// H_n(x) via recurrence relation
//
// Inputs: 2
// Outputs: 1
// Constants: 0
#include <math.h>
#include "ts.h"
ts_parameter_t const ts_hermite_p = { .n_inputs = 2, .n_outputs = 1, .n_constants = 0, .params_size = 0 };
uint_t ts_hermite_offset( ts_constant_t const *c )
{
( void )c;
return ( 0 );
}
int ts_hermite(
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_hermite_p );
(void)c;
for( uint_t i = 0; i < n; ++i )
{
fp_t xv = x[0][i];
if (x[1][i] < 0 || x[1][i] > 10000) { y[0][i] = 0; continue; }
uint_t n_val = (uint_t)x[1][i];
if( n_val == 0 )
{
y[0][i] = 1.0;
}
else if( n_val == 1 )
{
y[0][i] = 2.0 * xv;
}
else
{
fp_t h0 = 1.0;
fp_t h1 = 2.0 * xv;
for( uint_t k = 2; k <= n_val; ++k )
{
fp_t h2 = 2.0 * xv * h1 - 2.0 * (fp_t)(k - 1) * h0;
h0 = h1;
h1 = h2;
}
y[0][i] = h1;
}
}
return 0;
}
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