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// Catalan Number
//
// catalan - C(n)
//
// nth Catalan number: C(n) = (2n)! / ((n+1)! * n!)
//
// Inputs: 1 (n)
// Outputs: 1 (Catalan number)
// Constants: 0
#include <math.h>
#include "ts.h"
ts_parameter_t const ts_catalan_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 0, .params_size = 0 };
uint_t ts_catalan_offset( ts_constant_t const *c )
{
( void )c;
return ( 0 );
}
int ts_catalan(
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_catalan_p );
(void)c;
for( uint_t i = 0; i < n; ++i )
{
fp_t xv = x[0][i];
if (isnan(xv) || isinf(xv) || xv < 0 || xv != (fp_t)(uint_t)xv) {
y[0][i] = 0;
continue;
}
uint_t n_val = (uint_t)xv;
fp_t result = 1.0;
for( uint_t j = 0; j < n_val; ++j )
{
result *= (fp_t)(j + n_val + 1);
result /= (fp_t)(j + 1);
}
result /= (fp_t)(n_val + 1);
y[0][i] = result;
}
return 0;
}
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