// Momentum
//
// momentum
//
// Momentum
//
// C[t] - C[t-k]
//
// Inputs:    1
// Outputs:   1
// Constants: 1


#include "ts.h"

typedef struct {
    uint_t k;
} ts_momentum_params_t;

ts_parameter_t const ts_momentum_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 1, .params_size = sizeof(ts_momentum_params_t) };

uint_t ts_momentum_offset( ts_constant_t const *c )
{
	( void )c;
	return ( c ? ((ts_momentum_params_t *)c)->k : 0 );
}

int ts_momentum(
	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_momentum_p );
	if ( !c ) return -1;
	TS_CHECK_INPUT(x, x_n, n);
	uint_t k = ((ts_momentum_params_t *)c)->k;

	for( uint_t i = k; i < n; ++i )
	{
		y[0][i] = x[0][i] - x[0][i - k];
	}

	return 0;
}