https://github.com/stdlib-js/math-base-special-copysign
Return a double-precision floating-point number with the magnitude of x and the sign of y.
https://github.com/stdlib-js/math-base-special-copysign
bits copy copysign dbl double float float64 floating-point function ieee754 javascript math mathematics node node-js nodejs number sign special stdlib
Last synced: 7 months ago
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Return a double-precision floating-point number with the magnitude of x and the sign of y.
- Host: GitHub
- URL: https://github.com/stdlib-js/math-base-special-copysign
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-15T17:05:06.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2024-12-30T04:24:36.000Z (12 months ago)
- Last Synced: 2025-01-30T15:40:03.033Z (11 months ago)
- Topics: bits, copy, copysign, dbl, double, float, float64, floating-point, function, ieee754, javascript, math, mathematics, node, node-js, nodejs, number, sign, special, stdlib
- Language: Python
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 1.07 MB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
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# copysign
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Return a [double-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `y`.
## Installation
```bash
npm install @stdlib/math-base-special-copysign
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var copysign = require( '@stdlib/math-base-special-copysign' );
```
#### copysign( x, y )
Returns a [double-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `y`.
```javascript
var z = copysign( -3.14, 10.0 );
// returns 3.14
z = copysign( 3.14, -1.0 );
// returns -3.14
z = copysign( 1.0, -0.0 );
// returns -1.0
z = copysign( -3.14, -0.0 );
// returns -3.14
z = copysign( -0.0, 1.0 );
// returns 0.0
```
## Notes
- According to the [IEEE754][ieee754] standard, a `NaN` has a biased exponent equal to `2047`, a significand greater than `0`, and a sign bit equal to **either** `1` **or** `0`. In which case, `NaN` may not correspond to just one but many binary representations. Accordingly, care should be taken to ensure that `y` is **not** `NaN`; otherwise, behavior may be indeterminate.
## Examples
```javascript
var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var copysign = require( '@stdlib/math-base-special-copysign' );
var opts = {
'dtype': 'float64'
};
var x = uniform( 100, -50.0, 50.0, opts );
var y = uniform( 100, -5.0, 5.0, opts );
// Generate random double-precision floating-point numbers `x` and `y` and copy the sign of `y` to `x`...
logEachMap( 'x: %0.4f, y: %0.4f => %0.4f', x, y, copysign );
```
* * *
## C APIs
### Usage
```c
#include "stdlib/math/base/special/copysign.h"
```
#### stdlib_base_copysign( x, y )
Returns a [double-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `y`.
```c
double v = stdlib_base_copysign( -3.14, 10.0 );
// returns 3.14
double v = stdlib_base_copysign( 3.14, -1.0 );
// returns -3.14
```
The function accepts the following arguments:
- **x**: `[in] double` number from which to derive a magnitude.
- **y**: `[in] double` number from which to derive a sign.
```c
double stdlib_base_copysign( const double x, const double y );
```
### Examples
```c
#include "stdlib/math/base/special/copysign.h"
#include
int main( void ) {
const double x[] = { 3.14, -3.14, 0.0, 0.0/0.0 };
double y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_copysign( x[ i ], -3.0 );
printf( "copysign(%lf, %lf) = %lf\n", x[ i ], -3.0, y );
}
}
```
* * *
## See Also
- [`@stdlib/math-base/special/flipsign`][@stdlib/math/base/special/flipsign]: return a double-precision floating-point number with the magnitude of x and the sign of x\*y.
* * *
## Notice
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].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/math-base-special-copysign.svg
[npm-url]: https://npmjs.org/package/@stdlib/math-base-special-copysign
[test-image]: https://github.com/stdlib-js/math-base-special-copysign/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/math-base-special-copysign/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/math-base-special-copysign/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/math-base-special-copysign?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/math-base-special-copysign/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-copysign/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-copysign/tree/umd
[umd-readme]: https://github.com/stdlib-js/math-base-special-copysign/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/math-base-special-copysign/tree/esm
[esm-readme]: https://github.com/stdlib-js/math-base-special-copysign/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/math-base-special-copysign/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-copysign/main/LICENSE
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
[@stdlib/math/base/special/flipsign]: https://github.com/stdlib-js/math-base-special-flipsign