@stdlib/math-base-special-cabs2
v0.2.3TypeScript
Compute the squared absolute value of a double-precision complex floating-point number.
0/weekUpdated 2 days agoApache-2.0Unpacked: 39.6 KB
Published by The Stdlib Authors
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cabs2
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> Compute the squared [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
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-cabs2
Usage
`javascript`
var cabs2 = require( '@stdlib/math-base-special-cabs2' );
#### cabs2( z )
Computes the squared [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 = cabs2( new Complex128( 5.0, 3.0 ) );
// returns 34.0
`
Notes
- Be careful to avoid overflow and underflow.
- Depending on the environment, this function _may_ have better performance than computing the [absolute value][absolute-value] of a [complex][@stdlib/complex/float64/ctor] number and then squaring. Hence, where appropriate, consider using cabs2() over [cabs()][@stdlib/math/base/special/cabs].
Examples
`javascript
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var cabs2 = require( '@stdlib/math-base-special-cabs2' );
// Create a PRNG to generate uniformly distributed pseudorandom integers:
var rand = discreteUniform( -50, 50 );
// Compute the squared absolute value for a set of random numbers...
var z;
var i;
for ( i = 0; i < 100; i++ ) {
z = new Complex128( rand(), rand() );
console.log( 'cabs2(%s) = %d', z.toString(), cabs2( z ) );
}
`
*
C APIs
$3
`c`
#include "stdlib/math/base/special/cabs2.h"
#### stdlib_base_cabs2( z )
Computes the squared [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_cabs2( z );
// returns 34.0
`
The function accepts the following arguments:
- z: [in] stdlib_complex128_t input value.
`c`
double stdlib_base_cabs2( const stdlib_complex128_t z );
$3
`c
#include "stdlib/math/base/special/cabs2.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_cabs2( v );
stdlib_complex128_reim( v, &re, &im );
printf( "f(%lf + %lf) = %lf\n", re, im, y );
}
}
`
*
See Also
- [@stdlib/math-base/special/cabs][@stdlib/math/base/special/cabs]: compute the absolute value of a double-precision complex floating-point number.
- [@stdlib/math-base/special/abs2][@stdlib/math/base/special/abs2]: compute the squared 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].
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[stdlib]: https://github.com/stdlib-js/stdlib
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[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-cabs2/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-cabs2/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-cabs2/tree/umd
[umd-readme]: https://github.com/stdlib-js/math-base-special-cabs2/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/math-base-special-cabs2/tree/esm
[esm-readme]: https://github.com/stdlib-js/math-base-special-cabs2/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/math-base-special-cabs2/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-cabs2/main/LICENSE
[absolute-value]: https://en.wikipedia.org/wiki/Absolute_value
[@stdlib/math/base/special/cabs]: https://www.npmjs.com/package/@stdlib/math-base-special-cabs
[@stdlib/complex/float64/ctor]: https://www.npmjs.com/package/@stdlib/complex-float64-ctor
[@stdlib/math/base/special/abs2]: https://www.npmjs.com/package/@stdlib/math-base-special-abs2