lib/smoothstep.c


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// Smoothstep
//
// smoothstep - Smoothstep interpolation
//
// y[t] = x[t] <= 0 ? 0 : x[t] >= 1 ? 1 : 3*x[t]^2 - 2*x[t]^3
//
// X_n - 1
// Y_n - 1
// C_n - 0


#include "ts.h"


ts_parameter_t const ts_smoothstep_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 0, .params_size = 0 };


uint_t ts_smoothstep_offset( ts_constant_t const *c )
{
	( void )c;
	return ( 0 );
}

int ts_smoothstep(
	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_smoothstep_p );
	(void)c;
	for( uint_t i = 0; i < n; ++i )
	{
		fp_t xi = x[0][i];
		if ( xi <= 0 )
			y[0][i] = 0;
		else if ( xi >= 1 )
			y[0][i] = 1;
		else
		{
			fp_t x2 = xi * xi;
			y[0][i] = 3 * x2 - 2 * x2 * xi;
		}
	}
	return 0;
}