xlogy
Compute
x * ln(y)
so that the result is0
ifx = 0
.
Usage
var xlogy = require( '@stdlib/math/base/special/xlogy' );
xlogy( x, y )
Computes x * ln(y)
so that the result is 0
if x = 0
.
var out = xlogy( 3.0, 2.0 );
// returns ~2.079
out = xlogy( 1.5, 5.9 );
// returns ~2.662
out = xlogy( 0.9, 1.0 );
// returns 0.0
out = xlogy( 0.0, -2.0 );
// returns 0.0
out = xlogy( 1.5, NaN );
// returns NaN
out = xlogy( 0.0, NaN );
// returns NaN
out = xlogy( NaN, 2.3 );
// returns NaN
Examples
var randu = require( '@stdlib/random/base/randu' );
var xlogy = require( '@stdlib/math/base/special/xlogy' );
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( 'xlogy(%d, %d) = %d', x, y, xlogy( x, y ) );
}
C APIs
Usage
#include "stdlib/math/base/special/xlogy.h"
stdlib_base_xlogy( x, y )
Computes x * ln(y)
so that the result is 0
if x = 0
.
double v = stdlib_base_xlogy( 3.0, 2.0 );
// returns ~2.079
The function accepts the following arguments:
- x:
[in] double
input value. - y:
[in] double
input value.
double stdlib_base_xlogy( const double x, const double y );
Examples
#include "stdlib/math/base/special/xlogy.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_xlogy( x, y );
printf( "xlogy(%lf, %lf) = %lf\n", x, y, out );
}
}