modff

Decompose a single-precision floating-point number into integral and fractional parts.

Installation

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

Usage

var modff = require( '@stdlib/math-base-special-modff' );

modff( x )

Decomposes a single-precision floating-point number into integral and fractional parts, each having the same type and sign as x.

var parts = modff( 3.14 );
// returns [ 3.0, 0.1400001049041748 ]

parts = modff( +0.0 );
// returns [ +0.0, +0.0 ]

parts = modff( -0.0 );
// returns [ -0.0, -0.0 ]

parts = modff( Infinity );
// returns [ Infinity, +0.0 ]

parts = modff( -Infinity );
// returns [ -Infinity, -0.0 ]

parts = modff( NaN );
// returns [ NaN, NaN ]

modff.assign( x, out, stride, offset )

Decomposes a single-precision floating-point number into integral and fractional parts, each having the same type and sign as x, and assigns results to a provided output array.

var Float32Array = require( '@stdlib/array-float32' );

var out = new Float32Array( 2 );

var parts = modff.assign( 3.14, out, 1, 0 );
// returns <Float32Array>[ 3.0, 0.1400001049041748 ]

var bool = ( parts === out );
// returns true

Examples

var randu = require( '@stdlib/random-base-randu' );
var f32 = require( '@stdlib/number-float64-base-to-float32' );
var modff = require( '@stdlib/math-base-special-modff' );

var parts;
var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = f32( ( randu()*1000.0 ) - 500.0 );
    parts = modff( x );
    console.log( 'modff(%d) => integral: %d. fraction: %d.', x, parts[ 0 ], parts[ 1 ] );
}

C APIs

Usage

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

stdlib_base_modff( x, integral, frac )

Decomposes a single-precision floating-point number into integral and fractional parts, each having the same type and sign as x.

float integral;
float frac;

stdlib_base_modff( 4.0f, &integral, &frac );

The function accepts the following arguments:

• x: [in] float input value.
• integral: [out] float* destination for the integral part.
• frac: [out] float* destination for the fractional part.

void stdlib_base_modff( const float x, float *integral, float *frac );

Examples

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

int main( void ) {
    const float x[] = { 4.0f, 0.0f, -0.0f, 1.0f, -1.0f, 3.14f, -3.14f, 1.0e38f, -1.0e38f, 1.0f/0.0f, -1.0f/0.0f, 0.0f/0.0f };

    float integral;
    float frac;
    int i;
    for ( i = 0; i < 12; i++ ) {
        stdlib_base_modff( x[ i ], &integral, &frac );
        printf( "x: %f => integral: %f, frac: %f\n", x[ i ], integral, frac );
    }
}

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 © 2016-2026. The Stdlib Authors.