Compute a weighted arithmetic mean incrementally.
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we’ve built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
Compute a [weighted arithmetic mean][weighted-arithmetic-mean] incrementally.
math
\bar{x} = \frac{\displaystyle\sum_{i=0}^{n-1} w_{i} x_{i}}{\displaystyle\sum_{i=0}^{n-1} w_{i}}bash
npm install @stdlib/stats-incr-wmeanscript tag without installation and bundlers, use the [ES Module][es-module] available on the [esm][esm-url] branch (see [README][esm-readme]).deno][deno-url] branch (see [README][deno-readme] for usage intructions).umd][umd-url] branch (see [README][umd-readme]).javascript
var incrwmean = require( '@stdlib/stats-incr-wmean' );function which incrementally computes a [weighted arithmetic mean][weighted-arithmetic-mean].javascript
var accumulator = incrwmean();x and a weight w, the accumulator function returns an updated weighted mean. If not provided any input values, the accumulator function returns the current mean.javascript
var accumulator = incrwmean();
var mu = accumulator( 2.0, 1.0 );
// returns 2.0
mu = accumulator( 2.0, 0.5 );
// returns 2.0
mu = accumulator( 3.0, 1.5 );
// returns 2.5
mu = accumulator();
// returns 2.5NaN 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.javascript
var randu = require( '@stdlib/random-base-randu' );
var incrwmean = require( '@stdlib/stats-incr-wmean' );
var accumulator;
var v;
var w;
var i;
// Initialize an accumulator:
accumulator = incrwmean();
// For each simulated datum, update the weighted mean...
for ( i = 0; i < 100; i++ ) {
v = randu() * 100.0;
w = randu() * 100.0;
accumulator( v, w );
}
console.log( accumulator() );
