time-to-botec

Benchmark sampling in different programming languages
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README.md (3306B)

      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 # incrmeanabs2
     22 
     23 > Compute an [arithmetic mean][arithmetic-mean] of squared absolute values incrementally.
     24 
     25 <section class="intro">
     26 
     27 The [arithmetic mean][arithmetic-mean] of squared absolute values is defined as
     28 
     29 <!-- <equation class="equation" label="eq:arithmetic_mean_squared_absolute_values" align="center" raw="m = \frac{1}{n} \sum_{i=0}^{n-1} x_i^2" alt="Equation for the arithmetic mean of squared absolute values."> -->
     30 
     31 <div class="equation" align="center" data-raw-text="m = \frac{1}{n} \sum_{i=0}^{n-1} x_i^2" data-equation="eq:arithmetic_mean_squared_absolute_values">
     32     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@d08c5f0a491ba12729c84e40455fb75cf8666874/lib/node_modules/@stdlib/stats/incr/meanabs2/docs/img/equation_arithmetic_mean_squared_absolute_values.svg" alt="Equation for the arithmetic mean of squared absolute values.">
     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 incrmeanabs2 = require( '@stdlib/stats/incr/meanabs2' );
     48 ```
     49 
     50 #### incrmeanabs2()
     51 
     52 Returns an accumulator `function` which incrementally computes an [arithmetic mean][arithmetic-mean] of squared absolute values.
     53 
     54 ```javascript
     55 var accumulator = incrmeanabs2();
     56 ```
     57 
     58 #### accumulator( \[x] )
     59 
     60 If provided an input value `x`, the accumulator function returns an updated mean. If not provided an input value `x`, the accumulator function returns the current mean.
     61 
     62 ```javascript
     63 var accumulator = incrmeanabs2();
     64 
     65 var m = accumulator( 2.0 );
     66 // returns 4.0
     67 
     68 m = accumulator( -1.0 );
     69 // returns 2.5
     70 
     71 m = accumulator( -3.0 );
     72 // returns ~4.67
     73 
     74 m = accumulator();
     75 // returns ~4.67
     76 ```
     77 
     78 </section>
     79 
     80 <!-- /.usage -->
     81 
     82 <section class="notes">
     83 
     84 ## Notes
     85 
     86 -   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 **all** 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.
     87 
     88 </section>
     89 
     90 <!-- /.notes -->
     91 
     92 <section class="examples">
     93 
     94 ## Examples
     95 
     96 <!-- eslint no-undef: "error" -->
     97 
     98 ```javascript
     99 var randu = require( '@stdlib/random/base/randu' );
    100 var incrmeanabs2 = require( '@stdlib/stats/incr/meanabs2' );
    101 
    102 var accumulator;
    103 var v;
    104 var i;
    105 
    106 // Initialize an accumulator:
    107 accumulator = incrmeanabs2();
    108 
    109 // For each simulated datum, update the mean...
    110 for ( i = 0; i < 100; i++ ) {
    111     v = ( randu()*100.0 ) - 50.0;
    112     accumulator( v );
    113 }
    114 console.log( accumulator() );
    115 ```
    116 
    117 </section>
    118 
    119 <!-- /.examples -->
    120 
    121 <section class="links">
    122 
    123 [arithmetic-mean]: https://en.wikipedia.org/wiki/Arithmetic_mean
    124 
    125 </section>
    126 
    127 <!-- /.links -->