time-to-botec

Benchmark sampling in different programming languages
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README.md (3160B)

      1 <!--
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      3 @license Apache-2.0
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      5 Copyright (c) 2018 The Stdlib Authors.
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      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
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     11    http://www.apache.org/licenses/LICENSE-2.0
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     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.
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     19 -->
     20 
     21 # strides2offset
     22 
     23 > Determine the index offset which specifies the location of the first indexed value in a multidimensional array based on a stride array.
     24 
     25 <!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
     26 
     27 <section class="intro">
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     29 </section>
     30 
     31 <!-- /.intro -->
     32 
     33 <!-- Package usage documentation. -->
     34 
     35 <section class="usage">
     36 
     37 ## Usage
     38 
     39 ```javascript
     40 var strides2offset = require( '@stdlib/ndarray/base/strides2offset' );
     41 ```
     42 
     43 #### strides2offset( shape, strides )
     44 
     45 Returns the index offset which specifies the location of the first indexed value in a multidimensional array.
     46 
     47 ```javascript
     48 var offset = strides2offset( [ 3, 2 ], [ 2, 1 ] );
     49 // returns 0
     50 
     51 offset = strides2offset( [ 3, 2 ], [ -2, 1 ] );
     52 // returns 4
     53 ```
     54 
     55 </section>
     56 
     57 <!-- /.usage -->
     58 
     59 <!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
     60 
     61 <section class="notes">
     62 
     63 </section>
     64 
     65 <!-- /.notes -->
     66 
     67 <!-- Package usage examples. -->
     68 
     69 <section class="examples">
     70 
     71 ## Examples
     72 
     73 <!-- eslint no-undef: "error" -->
     74 
     75 ```javascript
     76 var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
     77 var shape2strides = require( '@stdlib/ndarray/base/shape2strides' );
     78 var numel = require( '@stdlib/ndarray/base/numel' );
     79 var randu = require( '@stdlib/random/base/randu' );
     80 var strides2offset = require( '@stdlib/ndarray/base/strides2offset' );
     81 
     82 var strides;
     83 var offset;
     84 var shape;
     85 var len;
     86 var arr;
     87 var i;
     88 var j;
     89 
     90 shape = [ 0, 0, 0 ];
     91 shape[ 0 ] = discreteUniform( 1, 10 );
     92 shape[ 1 ] = discreteUniform( 1, 10 );
     93 shape[ 2 ] = discreteUniform( 1, 10 );
     94 
     95 strides = shape2strides( shape, 'row-major' );
     96 len = numel( shape );
     97 
     98 arr = [];
     99 for ( i = 0; i < len; i++ ) {
    100     arr.push( i );
    101 }
    102 for ( i = 0; i < 100; i++ ) {
    103     j = discreteUniform( 0, shape.length-1 );
    104     strides[ j ] *= ( randu() < 0.5 ) ? -1 : 1;
    105     offset = strides2offset( shape, strides );
    106     console.log( 'arr[0][0][0] = %d', arr[ offset ] );
    107 }
    108 ```
    109 
    110 </section>
    111 
    112 <!-- /.examples -->
    113 
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    116 <section class="references">
    117 
    118 </section>
    119 
    120 <!-- /.references -->
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