time-to-botec

Benchmark sampling in different programming languages
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README.md (5962B)

      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
     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
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     19 -->
     20 
     21 # dnanmskmin
     22 
     23 > Calculate the minimum value of a double-precision floating-point strided array according to a mask, ignoring `NaN` values.
     24 
     25 <section class="intro">
     26 
     27 </section>
     28 
     29 <!-- /.intro -->
     30 
     31 <section class="usage">
     32 
     33 ## Usage
     34 
     35 ```javascript
     36 var dnanmskmin = require( '@stdlib/stats/base/dnanmskmin' );
     37 ```
     38 
     39 #### dnanmskmin( N, x, strideX, mask, strideMask )
     40 
     41 Computes the minimum value of a double-precision floating-point strided array `x` according to a `mask`, ignoring `NaN` values.
     42 
     43 ```javascript
     44 var Float64Array = require( '@stdlib/array/float64' );
     45 var Uint8Array = require( '@stdlib/array/uint8' );
     46 
     47 var x = new Float64Array( [ 1.0, -2.0, -4.0, 2.0, NaN ] );
     48 var mask = new Uint8Array( [ 0, 0, 1, 0, 0 ] );
     49 
     50 var v = dnanmskmin( x.length, x, 1, mask, 1 );
     51 // returns -2.0
     52 ```
     53 
     54 The function has the following parameters:
     55 
     56 -   **N**: number of indexed elements.
     57 -   **x**: input [`Float64Array`][@stdlib/array/float64].
     58 -   **strideX**: index increment for `x`.
     59 -   **mask**: mask [`Uint8Array`][@stdlib/array/uint8]. If a `mask` array element is `0`, the corresponding element in `x` is considered valid and **included** in computation. If a `mask` array element is `1`, the corresponding element in `x` is considered invalid/missing and **excluded** from computation.
     60 -   **strideMask**: index increment for `mask`.
     61 
     62 The `N` and `stride` parameters determine which elements are accessed at runtime. For example, to compute the minimum value of every other element in `x`,
     63 
     64 ```javascript
     65 var Float64Array = require( '@stdlib/array/float64' );
     66 var Uint8Array = require( '@stdlib/array/uint8' );
     67 var floor = require( '@stdlib/math/base/special/floor' );
     68 
     69 var x = new Float64Array( [ 1.0, 2.0, 7.0, -2.0, -4.0, 3.0, -5.0, -6.0 ] );
     70 var mask = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
     71 var N = floor( x.length / 2 );
     72 
     73 var v = dnanmskmin( N, x, 2, mask, 2 );
     74 // returns -4.0
     75 ```
     76 
     77 Note that indexing is relative to the first index. To introduce offsets, use [`typed array`][mdn-typed-array] views.
     78 
     79 <!-- eslint-disable stdlib/capitalized-comments -->
     80 
     81 ```javascript
     82 var Float64Array = require( '@stdlib/array/float64' );
     83 var Uint8Array = require( '@stdlib/array/uint8' );
     84 var floor = require( '@stdlib/math/base/special/floor' );
     85 
     86 var x0 = new Float64Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, -5.0, -6.0 ] );
     87 var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
     88 
     89 var mask0 = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
     90 var mask1 = new Uint8Array( mask0.buffer, mask0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
     91 
     92 var N = floor( x0.length / 2 );
     93 
     94 var v = dnanmskmin( N, x1, 2, mask1, 2 );
     95 // returns -2.0
     96 ```
     97 
     98 #### dnanmskmin.ndarray( N, x, strideX, offsetX, mask, strideMask, offsetMask )
     99 
    100 Computes the minimum value of a double-precision floating-point strided array according to a `mask`, ignoring `NaN` values and using alternative indexing semantics.
    101 
    102 ```javascript
    103 var Float64Array = require( '@stdlib/array/float64' );
    104 var Uint8Array = require( '@stdlib/array/uint8' );
    105 
    106 var x = new Float64Array( [ 1.0, -2.0, -4.0, 2.0, NaN ] );
    107 var mask = new Uint8Array( [ 0, 0, 1, 0, 0 ] );
    108 
    109 var v = dnanmskmin.ndarray( x.length, x, 1, 0, mask, 1, 0 );
    110 // returns -2.0
    111 ```
    112 
    113 The function has the following additional parameters:
    114 
    115 -   **offsetX**: starting index for `x`.
    116 -   **offsetMask**: starting index for `mask`.
    117 
    118 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 minimum value for every other value in `x` starting from the second value
    119 
    120 ```javascript
    121 var Float64Array = require( '@stdlib/array/float64' );
    122 var Uint8Array = require( '@stdlib/array/uint8' );
    123 var floor = require( '@stdlib/math/base/special/floor' );
    124 
    125 var x = new Float64Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, -5.0, -6.0 ] );
    126 var mask = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
    127 var N = floor( x.length / 2 );
    128 
    129 var v = dnanmskmin.ndarray( N, x, 2, 1, mask, 2, 1 );
    130 // returns -2.0
    131 ```
    132 
    133 </section>
    134 
    135 <!-- /.usage -->
    136 
    137 <section class="notes">
    138 
    139 ## Notes
    140 
    141 -   If `N <= 0`, both functions return `NaN`.
    142 
    143 </section>
    144 
    145 <!-- /.notes -->
    146 
    147 <section class="examples">
    148 
    149 ## Examples
    150 
    151 <!-- eslint no-undef: "error" -->
    152 
    153 ```javascript
    154 var randu = require( '@stdlib/random/base/randu' );
    155 var round = require( '@stdlib/math/base/special/round' );
    156 var Float64Array = require( '@stdlib/array/float64' );
    157 var Uint8Array = require( '@stdlib/array/uint8' );
    158 var dnanmskmin = require( '@stdlib/stats/base/dnanmskmin' );
    159 
    160 var mask;
    161 var x;
    162 var i;
    163 
    164 x = new Float64Array( 10 );
    165 mask = new Uint8Array( x.length );
    166 for ( i = 0; i < x.length; i++ ) {
    167     if ( randu() < 0.2 ) {
    168         mask[ i ] = 1;
    169     } else {
    170         mask[ i ] = 0;
    171     }
    172     if ( randu() < 0.1 ) {
    173         x[ i ] = NaN;
    174     } else {
    175         x[ i ] = round( (randu()*100.0) - 50.0 );
    176     }
    177 }
    178 console.log( x );
    179 console.log( mask );
    180 
    181 var v = dnanmskmin( x.length, x, 1, mask, 1 );
    182 console.log( v );
    183 ```
    184 
    185 </section>
    186 
    187 <!-- /.examples -->
    188 
    189 <section class="links">
    190 
    191 [@stdlib/array/float64]: https://www.npmjs.com/package/@stdlib/array-float64
    192 
    193 [@stdlib/array/uint8]: https://www.npmjs.com/package/@stdlib/array-uint8
    194 
    195 [mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
    196 
    197 </section>
    198 
    199 <!-- /.links -->