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    @stdlib/stats-incr-mgmean
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    0.0.6 • Public • Published

    incrmgmean

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    Compute a moving geometric mean incrementally.

    The geometric mean is defined as the nth root of a product of n numbers.

    Equation for the geometric mean.

    Installation

    npm install @stdlib/stats-incr-mgmean

    Usage

    var incrmgmean = require( '@stdlib/stats-incr-mgmean' );

    incrmgmean( window )

    Returns an accumulator function which incrementally computes a moving geometric mean. The window parameter defines the number of values over which to compute the moving geometric mean.

    var accumulator = incrmgmean( 3 );

    accumulator( [x] )

    If provided an input value x, the accumulator function returns an updated geometric mean. If not provided an input value x, the accumulator function returns the current geometric-mean.

    var accumulator = incrmgmean( 3 );
    
    var v = accumulator();
    // returns null
    
    // Fill the window...
    v = accumulator( 2.0 ); // [2.0]
    // returns 2.0
    
    v = accumulator( 1.0 ); // [2.0, 1.0]
    // returns ~1.41
    
    v = accumulator( 3.0 ); // [2.0, 1.0, 3.0]
    // returns ~1.82
    
    // Window begins sliding...
    v = accumulator( 7.0 ); // [1.0, 3.0, 7.0]
    // returns ~2.76
    
    v = accumulator( 5.0 ); // [3.0, 7.0, 5.0]
    // returns ~4.72
    
    v = accumulator();
    // returns ~4.72

    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 at least W-1 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.
    • As W values are needed to fill the window buffer, the first W-1 returned values are calculated from smaller sample sizes. Until the window is full, each returned value is calculated from all provided values.

    Examples

    var randu = require( '@stdlib/random-base-randu' );
    var incrmgmean = require( '@stdlib/stats-incr-mgmean' );
    
    var accumulator;
    var v;
    var i;
    
    // Initialize an accumulator:
    accumulator = incrmgmean( 5 );
    
    // For each simulated datum, update the moving geometric mean...
    for ( i = 0; i < 100; i++ ) {
        v = randu() * 100.0;
        accumulator( v );
    }
    console.log( accumulator() );

    See Also


    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.

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    License

    See LICENSE.

    Copyright

    Copyright © 2016-2022. The Stdlib Authors.

    Install

    npm i @stdlib/stats-incr-mgmean

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    57

    Version

    0.0.6

    License

    Apache-2.0

    Unpacked Size

    51.9 kB

    Total Files

    10

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser