time-to-botec

README.md (3978B)

---

 <!--
 
 @license Apache-2.0
 
 Copyright (c) 2019 The Stdlib Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
    http://www.apache.org/licenses/LICENSE-2.0
 
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 See the License for the specific language governing permissions and
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 # Reciprocal Square Root
 
 > Compute the reciprocal of the principal [square root][square-root] of a double-precision floating-point number.
 
 <section class="intro">
 
 The reciprocal of the principal [square root][square-root] is defined as
 
 <!-- <equation class="equation" label="eq:reciprocal_square_root" align="center" raw="\operatorname{rsqrt}(x)=\frac{1}{\sqrt{x}}" alt="Reciprocal square root"> -->
 
 <div class="equation" align="center" data-raw-text="\operatorname{rsqrt}(x)=\frac{1}{\sqrt{x}}" data-equation="eq:reciprocal_square_root">
     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@5b8dab9d7f516fcc8e1741900ae1569e95470c73/lib/node_modules/@stdlib/math/base/special/rsqrt/docs/img/equation_reciprocal_square_root.svg" alt="Reciprocal square root">
     <br>
 </div>
 
 <!-- </equation> -->
 
 </section>
 
 <!-- /.intro -->
 
 <section class="usage">
 
 ## 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
 ```
 
 </section>
 
 <!-- /.usage -->
 
 <section class="examples">
 
 ## Examples
 
 <!-- eslint no-undef: "error" -->
 
 ```javascript
 var randu = require( '@stdlib/random/base/randu' );
 var round = require( '@stdlib/math/base/special/round' );
 var rsqrt = require( '@stdlib/math/base/special/rsqrt' );
 
 var x;
 var i;
 
 for ( i = 0; i < 100; i++ ) {
     x = round( randu() * 100.0 );
     console.log( 'rsqrt(%d) = %d', x, rsqrt( x ) );
 }
 ```
 
 </section>
 
 <!-- /.examples -->
 
 <!-- C interface documentation. -->
 
 * * *
 
 <section class="c">
 
 ## C APIs
 
 <!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
 
 <section class="intro">
 
 </section>
 
 <!-- /.intro -->
 
 <!-- C usage documentation. -->
 
 <section class="usage">
 
 ### Usage
 
 ```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 );
 ```
 
 </section>
 
 <!-- /.usage -->
 
 <!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
 
 <section class="notes">
 
 </section>
 
 <!-- /.notes -->
 
 <!-- C API usage examples. -->
 
 <section class="examples">
 
 ### Examples
 
 ```c
 #include "stdlib/math/base/special/rsqrt.h"
 #include <stdio.h>
 
 int main() {
     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 );
     }
 }
 ```
 
 </section>
 
 <!-- /.examples -->
 
 </section>
 
 <!-- /.c -->
 
 <section class="links">
 
 [square-root]: https://en.wikipedia.org/wiki/Square_root
 
 </section>
 
 <!-- /.links -->