time-to-botec

Benchmark sampling in different programming languages
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README.md (4134B)

      1 <!--
      2 
      3 @license Apache-2.0
      4 
      5 Copyright (c) 2020 The Stdlib Authors.
      6 
      7 Licensed under the Apache License, Version 2.0 (the "License");
      8 you may not use this file except in compliance with the License.
      9 You may obtain a copy of the License at
     10 
     11    http://www.apache.org/licenses/LICENSE-2.0
     12 
     13 Unless required by applicable law or agreed to in writing, software
     14 distributed under the License is distributed on an "AS IS" BASIS,
     15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     16 See the License for the specific language governing permissions and
     17 limitations under the License.
     18 
     19 -->
     20 
     21 # Signum
     22 
     23 > [Signum][signum] function.
     24 
     25 <section class="intro">
     26 
     27 The [signum][signum] function is defined as
     28 
     29 <!-- <equation class="equation" label="eq:signum_function" align="center" raw="\operatorname{sign}(x) := \begin{cases} -1 & \textrm{if}\ x < 0 \\ 0 & \textrm{if}\ x = 0 \\ 1 & \textrm{if}\ x > 0 \end{cases}" alt="Signum function"> -->
     30 
     31 <div class="equation" align="center" data-raw-text="\operatorname{sign}(x) := \begin{cases} -1 &amp; \textrm{if}\ x &lt; 0 \\ 0 &amp; \textrm{if}\ x = 0 \\ 1 &amp; \textrm{if}\ x &gt; 0 \end{cases}" data-equation="eq:signum_function">
     32     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@4e38532a2ca3d2a641daa792a9c4c0fce3e749eb/lib/node_modules/@stdlib/math/base/special/signumf/docs/img/equation_signum_function.svg" alt="Signum function">
     33     <br>
     34 </div>
     35 
     36 <!-- </equation> -->
     37 
     38 for any real number `x`.
     39 
     40 </section>
     41 
     42 <!-- /.intro -->
     43 
     44 <section class="usage">
     45 
     46 ## Usage
     47 
     48 ```javascript
     49 var signumf = require( '@stdlib/math/base/special/signumf' );
     50 ```
     51 
     52 #### signumf( x )
     53 
     54 Evaluates the [signum][signum] function for a single-precision floating-point number.
     55 
     56 ```javascript
     57 var sign = signumf( -5.0 );
     58 // returns -1
     59 
     60 sign = signumf( 5.0 );
     61 // returns 1
     62 
     63 sign = signumf( -0.0 );
     64 // returns -0
     65 
     66 sign = signumf( 0.0 );
     67 // returns 0
     68 
     69 sign = signumf( NaN );
     70 // returns NaN
     71 ```
     72 
     73 </section>
     74 
     75 <!-- /.usage -->
     76 
     77 <section class="notes">
     78 
     79 ## Notes
     80 
     81 Table of results:
     82 
     83 | Value   | Sign  |
     84 | ------- | ----- |
     85 | `x > 0` | `+1`  |
     86 | `x < 0` | `-1`  |
     87 | `0`     | `0`   |
     88 | `-0`    | `-0`  |
     89 | `NaN`   | `NaN` |
     90 
     91 </section>
     92 
     93 <!-- /.notes -->
     94 
     95 <section class="examples">
     96 
     97 ## Examples
     98 
     99 <!-- eslint no-undef: "error" -->
    100 
    101 ```javascript
    102 var randu = require( '@stdlib/random/base/randu' );
    103 var round = require( '@stdlib/math/base/special/round' );
    104 var signumf = require( '@stdlib/math/base/special/signumf' );
    105 
    106 var sign;
    107 var x;
    108 var i;
    109 
    110 for ( i = 0; i < 100; i++ ) {
    111     x = round( randu()*100.0 ) - 50.0;
    112     sign = signumf( x );
    113     console.log( 'signum(%d) = %d', x, sign );
    114 }
    115 ```
    116 
    117 </section>
    118 
    119 <!-- /.examples -->
    120 
    121 <!-- C interface documentation. -->
    122 
    123 * * *
    124 
    125 <section class="c">
    126 
    127 ## C APIs
    128 
    129 <!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
    130 
    131 <section class="intro">
    132 
    133 </section>
    134 
    135 <!-- /.intro -->
    136 
    137 <!-- C usage documentation. -->
    138 
    139 <section class="usage">
    140 
    141 ### Usage
    142 
    143 ```c
    144 #include "stdlib/math/base/special/signumf.h"
    145 ```
    146 
    147 #### stdlib_base_signumf( x )
    148 
    149 Evaluates the [signum][signum] function for a single-precision floating-point number.
    150 
    151 ```c
    152 float y = stdlib_base_signumf( -9.0f );
    153 // returns -1.0f
    154 ```
    155 
    156 The function accepts the following arguments:
    157 
    158 -   **x**: `[in] float` input value.
    159 
    160 ```c
    161 float stdlib_base_signumf( const float x );
    162 ```
    163 
    164 </section>
    165 
    166 <!-- /.usage -->
    167 
    168 <!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
    169 
    170 <section class="notes">
    171 
    172 </section>
    173 
    174 <!-- /.notes -->
    175 
    176 <!-- C API usage examples. -->
    177 
    178 <section class="examples">
    179 
    180 ### Examples
    181 
    182 ```c
    183 #include "stdlib/math/base/special/signumf.h"
    184 #include <stdio.h>
    185 
    186 int main() {
    187     float x[] = { 3.14f, -3.14f, 0.0f, 0.0f/0.0f };
    188 
    189     float y;
    190     int i;
    191     for ( i = 0; i < 4; i++ ) {
    192         y = stdlib_base_signumf( x[ i ] );
    193         printf( "signum(%f) = %f\n", x[ i ], y );
    194     }
    195 }
    196 ```
    197 
    198 </section>
    199 
    200 <!-- /.examples -->
    201 
    202 </section>
    203 
    204 <!-- /.c -->
    205 
    206 <section class="links">
    207 
    208 [signum]: http://en.wikipedia.org/wiki/Sign_function
    209 
    210 </section>
    211 
    212 <!-- /.links -->