@stdlib/math-base-special-binomcoefln
v0.2.2
Published
Compute the natural logarithm of the binomial coefficient.
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Logarithm of Binomial Coefficient
Compute the natural logarithm of the binomial coefficient.
The natural logarithm of the binomial coefficient is
The binomial coefficient of two nonnegative integers n
and k
is defined as
The binomial coefficient can be generalized to negative integers n
as follows:
Installation
npm install @stdlib/math-base-special-binomcoefln
Usage
var binomcoefln = require( '@stdlib/math-base-special-binomcoefln' );
binomcoefln( n, k )
Evaluates the binomial coefficient of two integers n
and k
.
var v = binomcoefln( 8, 2 );
// returns ~3.332
v = binomcoefln( 0, 0 );
// returns 0.0
v = binomcoefln( -4, 2 );
// returns ~2.303
v = binomcoefln( 88, 3 );
// returns ~11.606
v = binomcoefln( NaN, 3 );
// returns NaN
v = binomcoefln( 5, NaN );
// returns NaN
v = binomcoefln( NaN, NaN );
// returns NaN
For negative k
, the function returns -Infinity
.
var v = binomcoefln( 2, -1 );
// returns -Infinity
v = binomcoefln( -3, -1 );
// returns -Infinity
The function returns NaN
for non-integer n
or k
.
var v = binomcoefln( 2, 1.5 );
// returns NaN
v = binomcoefln( 5.5, 2 );
// returns NaN
Examples
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var binomcoefln = require( '@stdlib/math-base-special-binomcoefln' );
var n;
var k;
var i;
for ( i = 0; i < 100; i++ ) {
n = round( (randu()*40.0) - 10.0 );
k = round( randu()*20.0 );
console.log( 'ln( %d choose %d ) = %d', n, k, binomcoefln( n, k ) );
}
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 © 2016-2024. The Stdlib Authors.