@stdlib/stats-incr-meanabs2 NPM

incrmeanabs2

Compute an arithmetic mean of squared absolute values incrementally.

The arithmetic mean of squared absolute values is defined as

Installation

npm install @stdlib/stats-incr-meanabs2

Usage

var incrmeanabs2 = require( '@stdlib/stats-incr-meanabs2' );

incrmeanabs2()

Returns an accumulator function which incrementally computes an arithmetic mean of squared absolute values.

var accumulator = incrmeanabs2();

accumulator( [x] )

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.

var accumulator = incrmeanabs2();

var m = accumulator( 2.0 );
// returns 4.0

m = accumulator( -1.0 );
// returns 2.5

m = accumulator( -3.0 );
// returns ~4.67

m = accumulator();
// returns ~4.67

Notes

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.

Examples

var randu = require( '@stdlib/random-base-randu' );
var incrmeanabs2 = require( '@stdlib/stats-incr-meanabs2' );

var accumulator;
var v;
var i;

// Initialize an accumulator:
accumulator = incrmeanabs2();

// For each simulated datum, update the mean...
for ( i = 0; i < 100; i++ ) {
    v = ( randu()*100.0 ) - 50.0;
    accumulator( v );
}
console.log( accumulator() );

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.