stdlib-js
<summary>
About stdlib...
</summary>
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.
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incrstdev
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
Compute a [corrected sample standard deviation][sample-stdev] incrementally.
bash
npm install @stdlib/stats-incr-stdev
javascript
var incrstdev = require( '@stdlib/stats-incr-stdev' );
#### incrstdev( [mean] )
Returns an accumulator function which incrementally computes a [corrected sample standard deviation][sample-stdev].
javascript
var accumulator = incrstdev();
If the mean is already known, provide a mean argument.
javascript
var accumulator = incrstdev( 3.0 );
#### accumulator( [x] )
If provided an input value x, the accumulator function returns an updated [corrected sample standard deviation][sample-stdev]. If not provided an input value x, the accumulator function returns the current [corrected sample standard deviation][sample-stdev].
javascript
var accumulator = incrstdev();
var s = accumulator( 2.0 );
// returns 0.0
s = accumulator( 1.0 ); // => sqrt(((2-1.5)^2+(1-1.5)^2) / (2-1))
// returns ~0.7071
s = accumulator( 3.0 ); // => sqrt(((2-2)^2+(1-2)^2+(3-2)^2) / (3-1))
// returns 1.0
s = accumulator();
// returns 1.0
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.
javascript
var randu = require( '@stdlib/random-base-randu' );
var incrstdev = require( '@stdlib/stats-incr-stdev' );
var accumulator;
var v;
var i;
// Initialize an accumulator:
accumulator = incrstdev();
// For each simulated datum, update the sample standard deviation...
for ( i = 0; i < 100; i++ ) {
v = randu() * 100.0;
accumulator( v );
}
console.log( accumulator() );
@stdlib/stats-incr/kurtosis][@stdlib/stats/incr/kurtosis]: compute a corrected sample excess kurtosis incrementally.
- [@stdlib/stats-incr/mean][@stdlib/stats/incr/mean]: compute an arithmetic mean incrementally.
- [@stdlib/stats-incr/mstdev][@stdlib/stats/incr/mstdev]: compute a moving corrected sample standard deviation incrementally.
- [@stdlib/stats-incr/skewness][@stdlib/stats/incr/skewness]: compute a corrected sample skewness incrementally.
- [@stdlib/stats-incr/summary][@stdlib/stats/incr/summary]: compute a statistical summary incrementally.
- [@stdlib/stats-incr/variance][@stdlib/stats/incr/variance]: compute an unbiased sample variance incrementally.
