time-to-botec

Benchmark sampling in different programming languages
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README.md (4614B)

      1 <!--
      2 
      3 @license Apache-2.0
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      5 Copyright (c) 2020 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.
     16 See the License for the specific language governing permissions and
     17 limitations under the License.
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     19 -->
     20 
     21 # ssumors
     22 
     23 > Calculate the sum of single-precision floating-point strided array elements using ordinary recursive summation.
     24 
     25 <section class="intro">
     26 
     27 </section>
     28 
     29 <!-- /.intro -->
     30 
     31 <section class="usage">
     32 
     33 ## Usage
     34 
     35 ```javascript
     36 var ssumors = require( '@stdlib/blas/ext/base/ssumors' );
     37 ```
     38 
     39 #### ssumors( N, x, stride )
     40 
     41 Computes the sum of single-precision floating-point strided array elements using ordinary recursive summation.
     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 = ssumors( N, x, 1 );
     50 // returns 1.0
     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 sum 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 = ssumors( N, x, 2 );
     69 // returns 5.0
     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 = ssumors( N, x1, 2 );
     86 // returns 5.0
     87 ```
     88 
     89 #### ssumors.ndarray( N, x, stride, offset )
     90 
     91 Computes the sum of single-precision floating-point strided array elements using ordinary recursive summation and 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 = ssumors.ndarray( N, x, 1, 0 );
    100 // returns 1.0
    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 sum of 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 = ssumors.ndarray( N, x, 2, 1 );
    117 // returns 5.0
    118 ```
    119 
    120 </section>
    121 
    122 <!-- /.usage -->
    123 
    124 <section class="notes">
    125 
    126 ## Notes
    127 
    128 -   If `N <= 0`, both functions return `0.0`.
    129 -   Ordinary recursive summation (i.e., a "simple" sum) is performant, but can incur significant numerical error. If performance is paramount and error tolerated, using ordinary recursive summation is acceptable; in all other cases, exercise due caution.
    130 
    131 </section>
    132 
    133 <!-- /.notes -->
    134 
    135 <section class="examples">
    136 
    137 ## Examples
    138 
    139 <!-- eslint no-undef: "error" -->
    140 
    141 ```javascript
    142 var randu = require( '@stdlib/random/base/randu' );
    143 var round = require( '@stdlib/math/base/special/round' );
    144 var Float32Array = require( '@stdlib/array/float32' );
    145 var ssumors = require( '@stdlib/blas/ext/base/ssumors' );
    146 
    147 var x;
    148 var i;
    149 
    150 x = new Float32Array( 10 );
    151 for ( i = 0; i < x.length; i++ ) {
    152     x[ i ] = round( randu()*100.0 );
    153 }
    154 console.log( x );
    155 
    156 var v = ssumors( x.length, x, 1 );
    157 console.log( v );
    158 ```
    159 
    160 </section>
    161 
    162 <!-- /.examples -->
    163 
    164 <section class="links">
    165 
    166 [@stdlib/array/float32]: https://www.npmjs.com/package/@stdlib/array-float32
    167 
    168 [mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
    169 
    170 </section>
    171 
    172 <!-- /.links -->