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# cabs [![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] > Compute the [absolute value][absolute-value] of a double-precision [complex][@stdlib/complex/float64/ctor] floating-point number.
The [absolute value][absolute-value] of a [complex][@stdlib/complex/float64/ctor] number is defined as
Absolute value
which corresponds to the length of a vector from the origin to a complex value plotted in the complex plane.
## Installation ```bash npm install @stdlib/math-base-special-cabs ```
## Usage ```javascript var cabs = require( '@stdlib/math-base-special-cabs' ); ``` #### cabs( z ) Computes an [absolute value][absolute-value] of a double-precision [complex][@stdlib/complex/float64/ctor] floating-point number. ```javascript var Complex128 = require( '@stdlib/complex-float64-ctor' ); var y = cabs( new Complex128( 5.0, 3.0 ) ); // returns ~5.83 ```
## Examples ```javascript var Complex128 = require( '@stdlib/complex-float64-ctor' ); var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ); var cabs = require( '@stdlib/math-base-special-cabs' ); var z; var i; for ( i = 0; i < 100; i++ ) { z = new Complex128( discreteUniform( -50, 50 ), discreteUniform( -50, 50 ) ); console.log( 'cabs(%s) = %d', z.toString(), cabs( z ) ); } ```
* * *
## C APIs
### Usage ```c #include "stdlib/math/base/special/cabs.h" ``` #### stdlib_base_cabs( z ) Computes the [absolute value][absolute-value] of a double-precision complex floating-point number. ```c #include "stdlib/complex/float64/ctor.h" stdlib_complex128_t z = stdlib_complex128( 5.0, 3.0 ); double y = stdlib_base_cabs( z ); // returns ~5.83 ``` The function accepts the following arguments: - **z**: `[in] stdlib_complex128_t` input value. ```c double stdlib_base_cabs( const stdlib_complex128_t complex z ); ```
### Examples ```c #include "stdlib/math/base/special/cabs.h" #include "stdlib/complex/float64/ctor.h" #include "stdlib/complex/float64/reim.h" #include int main( void ) { const stdlib_complex128_t x[] = { stdlib_complex128( 3.14, 1.0 ), stdlib_complex128( -3.14, -1.0 ), stdlib_complex128( 0.0, 0.0 ), stdlib_complex128( 0.0/0.0, 0.0/0.0 ) }; stdlib_complex128_t v; double re; double im; double y; int i; for ( i = 0; i < 4; i++ ) { v = x[ i ]; y = stdlib_base_cabs( v ); stdlib_complex128_reim( v, &re, &im ); printf( "cabs(%lf + %lfi) = %lf\n", re, im, y ); } } ```
* * * ## See Also - [`@stdlib/math-base/special/cabs2`][@stdlib/math/base/special/cabs2]: compute the squared absolute value of a double-precision complex floating-point number. - [`@stdlib/math-base/special/abs`][@stdlib/math/base/special/abs]: compute the absolute value of a double-precision floating-point number.
* * * ## 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 © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/math-base-special-cabs.svg [npm-url]: https://npmjs.org/package/@stdlib/math-base-special-cabs [test-image]: https://github.com/stdlib-js/math-base-special-cabs/actions/workflows/test.yml/badge.svg?branch=v0.2.3 [test-url]: https://github.com/stdlib-js/math-base-special-cabs/actions/workflows/test.yml?query=branch:v0.2.3 [coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/math-base-special-cabs/main.svg [coverage-url]: https://codecov.io/github/stdlib-js/math-base-special-cabs?branch=main [chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg [chat-url]: https://stdlib.zulipchat.com [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-cabs/tree/deno [deno-readme]: https://github.com/stdlib-js/math-base-special-cabs/blob/deno/README.md [umd-url]: https://github.com/stdlib-js/math-base-special-cabs/tree/umd [umd-readme]: https://github.com/stdlib-js/math-base-special-cabs/blob/umd/README.md [esm-url]: https://github.com/stdlib-js/math-base-special-cabs/tree/esm [esm-readme]: https://github.com/stdlib-js/math-base-special-cabs/blob/esm/README.md [branches-url]: https://github.com/stdlib-js/math-base-special-cabs/blob/main/branches.md [stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-cabs/main/LICENSE [absolute-value]: https://en.wikipedia.org/wiki/Absolute_value [@stdlib/complex/float64/ctor]: https://www.npmjs.com/package/@stdlib/complex-float64-ctor [@stdlib/math/base/special/cabs2]: https://www.npmjs.com/package/@stdlib/math-base-special-cabs2 [@stdlib/math/base/special/abs]: https://www.npmjs.com/package/@stdlib/math-base-special-abs