@stdlib/math-base-special-rsqrt
v0.2.3TypeScript
Compute the reciprocal square root of a double-precision floating-point number.
0/weekUpdated 4 days agoApache-2.0Unpacked: 39.0 KB
Published by The Stdlib Authors
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Reciprocal Square Root
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> Compute the reciprocal of the principal [square root][square-root] of a double-precision floating-point number.
The reciprocal of the principal [square root][square-root] is defined as
Installation
``bash`
npm install @stdlib/math-base-special-rsqrt
Usage
`javascript`
var rsqrt = require( '@stdlib/math-base-special-rsqrt' );
#### rsqrt( x )
Computes the reciprocal (inverse) square root of a double-precision floating-point number.
`javascript
var v = rsqrt( 1.0 );
// returns 1.0
v = rsqrt( 4.0 );
// returns 0.5
v = rsqrt( 100.0 );
// returns 0.1
v = rsqrt( 0.0 );
// returns Infinity
v = rsqrt( NaN );
// returns NaN
v = rsqrt( Infinity );
// returns 0.0
`
For negative numbers, the reciprocal square root is not defined.
`javascript`
var v = rsqrt( -4.0 );
// returns NaN
Examples
`javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var rsqrt = require( '@stdlib/math-base-special-rsqrt' );
var opts = {
'dtype': 'float64'
};
var x = discreteUniform( 100, 0, 100, opts );
logEachMap( 'rsqrt(%d) = %0.4f', x, rsqrt );
`
*
C APIs
$3
`c`
#include "stdlib/math/base/special/rsqrt.h"
#### stdlib_base_rsqrt( x )
Computes the reciprocal (inverse) [square root][square-root] of a double-precision floating-point number.
`c`
double y = stdlib_base_rsqrt( 4.0 );
// returns 0.5
The function accepts the following arguments:
- x: [in] double input value.
`c`
double stdlib_base_rsqrt( const double x );
$3
`c
#include "stdlib/math/base/special/rsqrt.h"
#include
int main( void ) {
const double x[] = { 3.14, 9.0, 0.0, 0.0/0.0 };
double y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_rsqrt( x[ i ] );
printf( "rsqrt(%lf) = %lf\n", x[ i ], y );
}
}
`
*
See Also
- [@stdlib/math-base/special/sqrt][@stdlib/math/base/special/sqrt]: compute the principal square root 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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[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-rsqrt/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-rsqrt/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-rsqrt/tree/umd
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[esm-url]: https://github.com/stdlib-js/math-base-special-rsqrt/tree/esm
[esm-readme]: https://github.com/stdlib-js/math-base-special-rsqrt/blob/esm/README.md
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-rsqrt/main/LICENSE
[square-root]: https://en.wikipedia.org/wiki/Square_root
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