# @stdlib/math-base-special-modf

0.3.0 • Public • Published

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.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

# modf

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

## Installation

`npm install @stdlib/math-base-special-modf`

## Usage

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

#### modf( x )

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

```var parts = modf( 3.14 );
// returns [ 3.0, 0.14000000000000012 ]

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

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

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

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

parts = modf( NaN );
// returns [ NaN, NaN ]```

#### modf.assign( x, out, stride, offset )

Decomposes a double-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 Float64Array = require( '@stdlib/array-float64' );

var out = new Float64Array( 2 );

var parts = modf.assign( 3.14, out, 1, 0 );
// returns <Float64Array>[ 3.0, 0.14000000000000012 ]

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

## Examples

```var randu = require( '@stdlib/random-base-randu' );
var modf = require( '@stdlib/math-base-special-modf' );

var parts;
var x;
var i;

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

## C APIs

### Usage

`#include "stdlib/math/base/special/modf.h"`

#### stdlib_base_modf( x, integral, frac )

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

```double integral;
double frac;

stdlib_base_modf( 4.0, &integral, &frac );```

The function accepts the following arguments:

• x: `[in] double` input value.
• frac: `[out] double*` destination for the integral part.
• exp: `[out] double*` destination for the fractional part.
`void stdlib_base_modf( const double x, double *integral, double *frac );`

### Examples

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

int main( void ) {
const double x[] = { 4.0, 0.0, -0.0, 1.0, -1.0, 3.14, -3.14, 1.0e308, -1.0e308, 1.0/0.0, -1.0/0.0, 0.0/0.0 };

double integral;
double frac;
int i;
for ( i = 0; i < 12; i++ ) {
stdlib_base_modf( x[ i ], &integral, &frac );
printf( "x: %lf => integral: %lf, frac: %lf\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.

## Package Sidebar

### Install

`npm i @stdlib/math-base-special-modf`

### Repository

github.com/stdlib-js/math-base-special-modf

stdlib.io

23

0.3.0

Apache-2.0

52.3 kB

17