xlog1py

Compute x * ln(y+1) so that the result is 0 if x = 0.

Usage

var xlog1py = require( '@stdlib/math/base/special/xlog1py' );

xlog1py( x, y )

Computes x * ln(y+1) so that the result is 0 if x = 0.

var out = xlog1py( 3.0, 2.0 );
// returns ~3.296

out = xlog1py( 1.5, 5.9 );
// returns ~2.897

out = xlog1py( 0.9, 1.0 );
// returns ~0.624

out = xlog1py( 1.0, 0.0 );
// returns 0.0

out = xlog1py( 0.0, -2.0 );
// returns 0.0

out = xlog1py( 1.5, NaN );
// returns NaN

out = xlog1py( 0.0, NaN );
// returns NaN

out = xlog1py( NaN, 2.3 );
// returns NaN

Examples

var randu = require( '@stdlib/random/base/randu' );
var xlog1py = require( '@stdlib/math/base/special/xlog1py' );

var x;
var y;
var i;

for ( i = 0; i < 100; i++ ) {
    x = randu();
    if ( x < 0.5 ) {
        x = 0.0;
    }
    y = ( randu() * 20.0 ) - 5.0;
    console.log( 'xlog1py(%d, %d) = %d', x, y, xlog1py( x, y ) );
}

C APIs

Usage

#include "stdlib/math/base/special/xlog1py.h"

stdlib_base_xlog1py( x, y )

Computes x * ln(y+1) so that the result is 0 if x = 0.

double v = stdlib_base_xlog1py( 3.0, 2.0 );
// returns ~3.296

The function accepts the following arguments:

x: [in] double input value.
y: [in] double input value.

double stdlib_base_xlog1py( const double x, const double y );

Examples

#include "stdlib/math/base/special/xlog1py.h"
#include <stdio.h>
#include <stdlib.h>

int main( void ) {
    double out;
    double x;
    double y;
    int i;

    for ( i = 0; i < 100; i++ ) {
        x = ( (double)rand() / (double)RAND_MAX ) * 100.0;
        y = ( (double)rand() / (double)RAND_MAX ) * 5.0;
        out = stdlib_base_xlog1py( x, y );
        printf( "xlog1py(%lf, %lf) = %lf\n", x, y, out );
    }
}