time-to-botec

Benchmark sampling in different programming languages
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README.md (4338B)

      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
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     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.
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     19 -->
     20 
     21 # smaxabs
     22 
     23 > Calculate the maximum absolute value of a single-precision floating-point strided array.
     24 
     25 <section class="intro">
     26 
     27 </section>
     28 
     29 <!-- /.intro -->
     30 
     31 <section class="usage">
     32 
     33 ## Usage
     34 
     35 ```javascript
     36 var smaxabs = require( '@stdlib/stats/base/smaxabs' );
     37 ```
     38 
     39 #### smaxabs( N, x, stride )
     40 
     41 Computes the maximum absolute value of a single-precision floating-point strided array `x`.
     42 
     43 ```javascript
     44 var Float32Array = require( '@stdlib/array/float32' );
     45 
     46 var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );
     47 var N = x.length;
     48 
     49 var v = smaxabs( N, x, 1 );
     50 // returns 2.0
     51 ```
     52 
     53 The function has the following parameters:
     54 
     55 -   **N**: number of indexed elements.
     56 -   **x**: input [`Float32Array`][@stdlib/array/float32].
     57 -   **stride**: index increment for `x`.
     58 
     59 The `N` and `stride` parameters determine which elements in `x` are accessed at runtime. For example, to compute the maximum absolute value of every other element in `x`,
     60 
     61 ```javascript
     62 var Float32Array = require( '@stdlib/array/float32' );
     63 var floor = require( '@stdlib/math/base/special/floor' );
     64 
     65 var x = new Float32Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0 ] );
     66 var N = floor( x.length / 2 );
     67 
     68 var v = smaxabs( N, x, 2 );
     69 // returns 4.0
     70 ```
     71 
     72 Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
     73 
     74 <!-- eslint-disable stdlib/capitalized-comments -->
     75 
     76 ```javascript
     77 var Float32Array = require( '@stdlib/array/float32' );
     78 var floor = require( '@stdlib/math/base/special/floor' );
     79 
     80 var x0 = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
     81 var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
     82 
     83 var N = floor( x0.length / 2 );
     84 
     85 var v = smaxabs( N, x1, 2 );
     86 // returns 4.0
     87 ```
     88 
     89 #### smaxabs.ndarray( N, x, stride, offset )
     90 
     91 Computes the maximum absolute value of a single-precision floating-point strided array using alternative indexing semantics.
     92 
     93 ```javascript
     94 var Float32Array = require( '@stdlib/array/float32' );
     95 
     96 var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );
     97 var N = x.length;
     98 
     99 var v = smaxabs.ndarray( N, x, 1, 0 );
    100 // returns 2.0
    101 ```
    102 
    103 The function has the following additional parameters:
    104 
    105 -   **offset**: starting index for `x`.
    106 
    107 While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the `offset` parameter supports indexing semantics based on a starting index. For example, to calculate the maximum absolute value for every other value in `x` starting from the second value
    108 
    109 ```javascript
    110 var Float32Array = require( '@stdlib/array/float32' );
    111 var floor = require( '@stdlib/math/base/special/floor' );
    112 
    113 var x = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
    114 var N = floor( x.length / 2 );
    115 
    116 var v = smaxabs.ndarray( N, x, 2, 1 );
    117 // returns 4.0
    118 ```
    119 
    120 </section>
    121 
    122 <!-- /.usage -->
    123 
    124 <section class="notes">
    125 
    126 ## Notes
    127 
    128 -   If `N <= 0`, both functions return `NaN`.
    129 
    130 </section>
    131 
    132 <!-- /.notes -->
    133 
    134 <section class="examples">
    135 
    136 ## Examples
    137 
    138 <!-- eslint no-undef: "error" -->
    139 
    140 ```javascript
    141 var randu = require( '@stdlib/random/base/randu' );
    142 var round = require( '@stdlib/math/base/special/round' );
    143 var Float32Array = require( '@stdlib/array/float32' );
    144 var smaxabs = require( '@stdlib/stats/base/smaxabs' );
    145 
    146 var x;
    147 var i;
    148 
    149 x = new Float32Array( 10 );
    150 for ( i = 0; i < x.length; i++ ) {
    151     x[ i ] = round( (randu()*100.0) - 50.0 );
    152 }
    153 console.log( x );
    154 
    155 var v = smaxabs( x.length, x, 1 );
    156 console.log( v );
    157 ```
    158 
    159 </section>
    160 
    161 <!-- /.examples -->
    162 
    163 <section class="links">
    164 
    165 [@stdlib/array/float32]: https://www.npmjs.com/package/@stdlib/array-float32
    166 
    167 [mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
    168 
    169 </section>
    170 
    171 <!-- /.links -->