Rising Factorial

Compute the rising factorial.

Installation

npm install @stdlib/math-base-special-rising-factorial

Usage

var risingFactorial = require( '@stdlib/math-base-special-rising-factorial' );

risingFactorial( x, n )

Evaluates the rising factorial of x and n.

var v = risingFactorial( 0.9, 5 );
// returns ~94.766

v = risingFactorial( -9.0, 3 );
// returns -504.0

v = risingFactorial( 0.0, 2 );
// returns 0.0

v = risingFactorial( 3.0, -2 );
// returns 0.5

v = risingFactorial( NaN, 3 );
// returns NaN

v = risingFactorial( 5.0, NaN );
// returns NaN

v = risingFactorial( NaN, NaN );
// returns NaN

The function returns NaN for non-integer n.

var v = risingFactorial( 2.0, 1.5 );
// returns NaN

Examples

var randu = require( '@stdlib/random-base-randu' );
var ceil = require( '@stdlib/math-base-special-ceil' );
var risingFactorial = require( '@stdlib/math-base-special-rising-factorial' );

var n;
var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = ( randu()*40.0 ) - 20.0;
    n = ceil( ( randu()*40.0 ) - 20.0 );
    console.log( 'risingFactorial(%d,%d) = %d', x, n, risingFactorial( x, n ) );
}

C APIs

Usage

#include "stdlib/math/base/special/rising_factorial.h"

stdlib_base_rising_factorial( x, n )

Evaluates the rising factorial of x and n.

double out = stdlib_base_rising_factorial( 0.9, 5 );
// returns ~94.766

out = stdlib_base_rising_factorial( -9.0, 3 );
// returns -504.0

The function accepts the following arguments:

• x: [in] double first function parameter.
• n: [in] int32_t second function parameter.

double stdlib_base_rising_factorial( const double x, const int32_t n );

Examples

#include "stdlib/math/base/special/rising_factorial.h"
#include <stdio.h>
#include <stdint.h>

int main( void ) {
    const double x[] = { -10.0, -7.78, -5.56, -3.33, -1.11, 1.11, 3.33, 5.56, 7.78, 10.0 };
    const int32_t n[] = { 5, 4, 3, 2, 1, 0, -1, -2, -3, -4 };

    double v;
    int i;
    for ( i = 0; i < 10; i++ ) {
        v = stdlib_base_rising_factorial( x[ i ], n[ i ] );
        printf( "risingFactorial(%lf, %d) = %lf\n", x[ i ], n[ i ], v );
    }
}

See Also

• @stdlib/math-base/special/falling-factorial: compute the falling factorial.

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.

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Copyright

Copyright © 2016-2026. The Stdlib Authors.