time-to-botec

Benchmark sampling in different programming languages
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README.md (3885B)

      1 <!--
      2 
      3 @license Apache-2.0
      4 
      5 Copyright (c) 2018 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 # incrmgmean
     22 
     23 > Compute a moving [geometric mean][geometric-mean] incrementally.
     24 
     25 <section class="intro">
     26 
     27 The [geometric mean][geometric-mean] is defined as the nth root of a product of _n_ numbers.
     28 
     29 <!-- <equation class="equation" label="eq:geometric_mean" align="center" raw="\biggl( \prod_{i=0}^{n-1} \biggr)^{\frac{1}{n}} = \sqrt[n]{x_0 x_1 \cdots x_{n-1}}" alt="Equation for the geometric mean."> -->
     30 
     31 <div class="equation" align="center" data-raw-text="\biggl( \prod_{i=0}^{n-1} \biggr)^{\frac{1}{n}} = \sqrt[n]{x_0 x_1 \cdots x_{n-1}}" data-equation="eq:geometric_mean">
     32     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@49d8cabda84033d55d7b8069f19ee3dd8b8d1496/lib/node_modules/@stdlib/stats/incr/mgmean/docs/img/equation_geometric_mean.svg" alt="Equation for the geometric mean.">
     33     <br>
     34 </div>
     35 
     36 <!-- </equation> -->
     37 
     38 </section>
     39 
     40 <!-- /.intro -->
     41 
     42 <section class="usage">
     43 
     44 ## Usage
     45 
     46 ```javascript
     47 var incrmgmean = require( '@stdlib/stats/incr/mgmean' );
     48 ```
     49 
     50 #### incrmgmean( window )
     51 
     52 Returns an accumulator `function` which incrementally computes a moving [geometric mean][geometric-mean]. The `window` parameter defines the number of values over which to compute the moving [geometric mean][geometric-mean].
     53 
     54 ```javascript
     55 var accumulator = incrmgmean( 3 );
     56 ```
     57 
     58 #### accumulator( \[x] )
     59 
     60 If provided an input value `x`, the accumulator function returns an updated [geometric mean][geometric-mean]. If not provided an input value `x`, the accumulator function returns the current [geometric-mean][geometric-mean].
     61 
     62 ```javascript
     63 var accumulator = incrmgmean( 3 );
     64 
     65 var v = accumulator();
     66 // returns null
     67 
     68 // Fill the window...
     69 v = accumulator( 2.0 ); // [2.0]
     70 // returns 2.0
     71 
     72 v = accumulator( 1.0 ); // [2.0, 1.0]
     73 // returns ~1.41
     74 
     75 v = accumulator( 3.0 ); // [2.0, 1.0, 3.0]
     76 // returns ~1.82
     77 
     78 // Window begins sliding...
     79 v = accumulator( 7.0 ); // [1.0, 3.0, 7.0]
     80 // returns ~2.76
     81 
     82 v = accumulator( 5.0 ); // [3.0, 7.0, 5.0]
     83 // returns ~4.72
     84 
     85 v = accumulator();
     86 // returns ~4.72
     87 ```
     88 
     89 </section>
     90 
     91 <!-- /.usage -->
     92 
     93 <section class="notes">
     94 
     95 ## Notes
     96 
     97 -   Input values are **not** type checked. If provided `NaN` or a value which, when used in computations, results in `NaN`, the accumulated value is `NaN` for **at least** `W-1` future invocations. If non-numeric inputs are possible, you are advised to type check and handle accordingly **before** passing the value to the accumulator function.
     98 -   As `W` values are needed to fill the window buffer, the first `W-1` returned values are calculated from smaller sample sizes. Until the window is full, each returned value is calculated from all provided values.
     99 
    100 </section>
    101 
    102 <!-- /.notes -->
    103 
    104 <section class="examples">
    105 
    106 ## Examples
    107 
    108 <!-- eslint no-undef: "error" -->
    109 
    110 ```javascript
    111 var randu = require( '@stdlib/random/base/randu' );
    112 var incrmgmean = require( '@stdlib/stats/incr/mgmean' );
    113 
    114 var accumulator;
    115 var v;
    116 var i;
    117 
    118 // Initialize an accumulator:
    119 accumulator = incrmgmean( 5 );
    120 
    121 // For each simulated datum, update the moving geometric mean...
    122 for ( i = 0; i < 100; i++ ) {
    123     v = randu() * 100.0;
    124     accumulator( v );
    125 }
    126 console.log( accumulator() );
    127 ```
    128 
    129 </section>
    130 
    131 <!-- /.examples -->
    132 
    133 <section class="links">
    134 
    135 [geometric-mean]: https://en.wikipedia.org/wiki/Geometric_mean
    136 
    137 </section>
    138 
    139 <!-- /.links -->