stdlib-js
<summary>
About stdlib...
</summary>
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
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Gamma Function
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[Gamma][gamma-function] function.
n is a positive integer,
z, except for nonpositive integers, the [gamma function][gamma-function] can be expressed as an infinite product
where γ ≈ 0.577216 is the [Euler–Mascheroni constant][@stdlib/constants/float64/eulergamma].
bash
npm install @stdlib/math-base-special-gamma
javascript
var gamma = require( '@stdlib/math-base-special-gamma' );
#### gamma( x )
Evaluates the [gamma function][gamma-function].
javascript
var v = gamma( 4.0 );
// returns 6.0
v = gamma( -1.5 );
// returns ~2.363
v = gamma( -0.5 );
// returns ~-3.545
v = gamma( 0.5 );
// returns ~1.772
v = gamma( 0.0 );
// returns Infinity
v = gamma( -0.0 );
// returns -Infinity
v = gamma( NaN );
// returns NaN
javascript
var linspace = require( '@stdlib/array-base-linspace' );
var gamma = require( '@stdlib/math-base-special-gamma' );
var x = linspace( -10.0, 10.0, 100 );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( 'x: %d, f(x): %d', x[ i ], gamma( x[ i ] ) );
}
c
#include "stdlib/math/base/special/gamma.h"
#### stdlib_base_gamma( x )
Evaluates the [gamma function][gamma-function].
c
double out = stdlib_base_gamma( 4.0 );
// returns 6.0
out = stdlib_base_gamma( -1.5 );
// returns ~2.363
The function accepts the following arguments:
- x: [in] double input value.
c
double stdlib_base_gamma( const double x );
c
#include "stdlib/math/base/special/gamma.h"
#include <stdio.h>
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_gamma( x[ i ] );
printf( "gamma(%lf) = %lf\n", x[ i ], y );
}
}
@stdlib/math-base/special/gamma1pm1][@stdlib/math/base/special/gamma1pm1]: compute gamma(x+1) - 1.
- [@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.
- [@stdlib/math-base/special/gammaln][@stdlib/math/base/special/gammaln]: natural logarithm of the gamma function.
