stdlib-js / math-base-special-xlogy

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

xlogy

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

Installation

npm install @stdlib/math-base-special-xlogy

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch.
• If you are using Deno, visit the deno branch.
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch.

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

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 ) );
}

---

See Also

• @stdlib/math-base/special/ln: natural logarithm.
• @stdlib/math-base/special/xlog1py: compute x * ln(y+1) so that the result is 0 if x = 0.

---

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

---

License

See LICENSE.

Copyright

Copyright © 2016-2023. The Stdlib Authors.