time-to-botec

Benchmark sampling in different programming languages
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README.md (3204B)

      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 # incrsum
     22 
     23 > Compute a sum incrementally.
     24 
     25 <section class="intro">
     26 
     27 The sum is defined as
     28 
     29 <!-- <equation class="equation" label="eq:sum" align="center" raw="s = \sum_{i=0}^{n-1} x_i" alt="Equation for the sum."> -->
     30 
     31 <div class="equation" align="center" data-raw-text="s = \sum_{i=0}^{n-1} x_i" data-equation="eq:sum">
     32     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@49d8cabda84033d55d7b8069f19ee3dd8b8d1496/lib/node_modules/@stdlib/stats/incr/sum/docs/img/equation_sum.svg" alt="Equation for the sum.">
     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 incrsum = require( '@stdlib/stats/incr/sum' );
     48 ```
     49 
     50 #### incrsum()
     51 
     52 Returns an accumulator `function` which incrementally computes a sum.
     53 
     54 ```javascript
     55 var accumulator = incrsum();
     56 ```
     57 
     58 #### accumulator( \[x] )
     59 
     60 If provided an input value `x`, the accumulator function returns an updated sum. If not provided an input value `x`, the accumulator function returns the current sum.
     61 
     62 ```javascript
     63 var accumulator = incrsum();
     64 
     65 var sum = accumulator( 2.0 );
     66 // returns 2.0
     67 
     68 sum = accumulator( 1.0 );
     69 // returns 3.0
     70 
     71 sum = accumulator( 3.0 );
     72 // returns 6.0
     73 
     74 sum = accumulator();
     75 // returns 6.0
     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 -   For long running accumulations or accumulations of large numbers, care should be taken to prevent overflow.
     88 
     89 </section>
     90 
     91 <!-- /.notes -->
     92 
     93 <section class="examples">
     94 
     95 ## Examples
     96 
     97 <!-- eslint no-undef: "error" -->
     98 
     99 ```javascript
    100 var randu = require( '@stdlib/random/base/randu' );
    101 var incrsum = require( '@stdlib/stats/incr/sum' );
    102 
    103 var accumulator;
    104 var v;
    105 var i;
    106 
    107 // Initialize an accumulator:
    108 accumulator = incrsum();
    109 
    110 // For each simulated datum, update the sum...
    111 for ( i = 0; i < 100; i++ ) {
    112     v = randu() * 100.0;
    113     accumulator( v );
    114 }
    115 console.log( accumulator() );
    116 ```
    117 
    118 </section>
    119 
    120 <!-- /.examples -->
    121 
    122 * * *
    123 
    124 <section class="references">
    125 
    126 ## References
    127 
    128 -   Klein, Andreas. 2005. "A Generalized Kahan-Babuška-Summation-Algorithm." _Computing_ 76 (3): 279–93. doi:[10.1007/s00607-005-0139-x][@klein:2005a].
    129 
    130 </section>
    131 
    132 <!-- /.references -->
    133 
    134 <section class="links">
    135 
    136 [@klein:2005a]: https://doi.org/10.1007/s00607-005-0139-x
    137 
    138 </section>
    139 
    140 <!-- /.links -->