lib/secant_hyperbolic_inverse.c


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// Inverse Hyperbolic Secant
//
// secant_hyperbolic_inverse - asech
//
// f( x ) = asech( x )
//        = ln( ( 1 / x ) + √( ( 1 / x^2 ) - 1 ) )    0 < x ≤ 1
//
// X_n - 1
// Y_n - 1
// C_n - 0


#include <math.h>
#include "ts.h"


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


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

int ts_secant_hyperbolic_inverse(
	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_secant_hyperbolic_inverse_p );
	(void)c;
	for( uint_t i = 0; i < n; ++i )
	{
		fp_t xi = x[0][i];
		y[0][i] = ( xi > 0 && xi <= 1.0 ) ? acosh( _ts_reciprocal( xi ) ) : 0;
	}
	return 0;
}