Natural logarithm of the gamma function.
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> [Natural logarithm][@stdlib/math/base/special/ln] of the [gamma][@stdlib/math/base/special/gamma] function.
``bash`
npm install @stdlib/math-base-special-gammaln
`javascript`
var gammaln = require( '@stdlib/math-base-special-gammaln' );
#### gammaln( x )
Evaluates the [natural logarithm][@stdlib/math/base/special/ln] of the [gamma function][@stdlib/math/base/special/gamma].
`javascript
var v = gammaln( 2.0 );
// returns 0.0
v = gammaln( 1.0 );
// returns 0.0
v = gammaln( 4.0 );
// returns ~1.792
v = gammaln( -0.5 );
// returns ~1.266
v = gammaln( 0.5 );
// returns ~0.572
v = gammaln( 0.0 );
// returns Infinity
v = gammaln( NaN );
// returns NaN
`
`javascript
var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var gammaln = require( '@stdlib/math-base-special-gammaln' );
var opts = {
'dtype': 'float64'
};
var x = uniform( 100, -10.0, 10.0, opts );
logEachMap( 'x: %0.4f, f(x): %0.4f', x, gammaln );
`
*
`c`
#include "stdlib/math/base/special/gammaln.h"
#### stdlib_base_gammaln( x )
Evaluates the [natural logarithm][@stdlib/math/base/special/ln] of the [gamma function][@stdlib/math/base/special/gamma].
`c
double out = stdlib_base_gammaln( 2.0 );
// returns 0.0
out = stdlib_base_gammaln( 4.0 );
// returns ~1.792
`
The function accepts the following arguments:
- x: [in] double input value.
`c`
double stdlib_base_gammaln( const double x );
`c
#include "stdlib/math/base/special/gammaln.h"
#include
#include
int main( void ) {
const double x[] = { 4.0, -1.5, -0.5, 0.5 };
double y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_gammaln( x[ i ] );
printf( "gammaln(%lf) = %lf\n", x[ i ], y );
}
}
`
*
- [@stdlib/math-base/special/gamma][@stdlib/math/base/special/gamma]: gamma function.
- [@stdlib/math-base/special/gammainc][@stdlib/math/base/special/gammainc]: incomplete gamma function.
- [@stdlib/math-base/special/gammaincinv][@stdlib/math/base/special/gammaincinv]: inverse incomplete gamma function.
*
This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].
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---
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[umd]: https://github.com/umdjs/umd
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[deno-readme]: https://github.com/stdlib-js/math-base-special-gammaln/blob/deno/README.md
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[esm-url]: https://github.com/stdlib-js/math-base-special-gammaln/tree/esm
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[branches-url]: https://github.com/stdlib-js/math-base-special-gammaln/blob/main/branches.md
[@stdlib/math/base/special/ln]: https://www.npmjs.com/package/@stdlib/math-base-special-ln
[@stdlib/math/base/special/gamma]: https://www.npmjs.com/package/@stdlib/math-base-special-gamma
[@stdlib/math/base/special/gammainc]: https://www.npmjs.com/package/@stdlib/math-base-special-gammainc
[@stdlib/math/base/special/gammaincinv]: https://www.npmjs.com/package/@stdlib/math-base-special-gammaincinv