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    @stdlib/stats-base-dists-frechet-mean
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    Mean

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    Fréchet distribution expected value.

    The expected value for a Fréchet random variable shape α > 0, scale s > 0, and location parameter m is

    Expected value for a Fréchet distribution.

    where Γ is the gamma function.

    Installation

    npm install @stdlib/stats-base-dists-frechet-mean

    Usage

    var mean = require( '@stdlib/stats-base-dists-frechet-mean' );

    mean( alpha, s, m )

    Returns the expected value for a Fréchet distribution with shape alpha > 0, scale s > 0, and location parameter m.

    var y = mean( 2.0, 1.0, 1.0 );
    // returns ~2.772
    
    y = mean( 4.0, 4.0, -1.0 );
    // returns ~3.902
    
    y = mean( 1.0, 1.0, 2.0 );
    // returns Infinity

    If provided NaN as any argument, the function returns NaN.

    var y = mean( NaN, 1.0, -2.0 );
    // returns NaN
    
    y = mean( 1.0, NaN, -2.0 );
    // returns NaN
    
    y = mean( 1.0, 1.0, NaN );
    // returns NaN

    If provided alpha <= 0, the function returns NaN.

    var y = mean( 0.0, 3.0, 2.0 );
    // returns NaN
    
    y = mean( 0.0, -1.0, 2.0 );
    // returns NaN

    If provided s <= 0, the function returns NaN.

    var y = mean( 1.0, 0.0, 2.0 );
    // returns NaN
    
    y = mean( 1.0, -1.0, 2.0 );
    // returns NaN

    Examples

    var randu = require( '@stdlib/random-base-randu' );
    var EPS = require( '@stdlib/constants-float64-eps' );
    var mean = require( '@stdlib/stats-base-dists-frechet-mean' );
    
    var alpha;
    var m;
    var s;
    var y;
    var i;
    
    for ( i = 0; i < 10; i++ ) {
        alpha = ( randu()*20.0 ) + EPS;
        s = ( randu()*20.0 ) + EPS;
        m = ( randu()*20.0 ) - 40.0;
        y = mean( alpha, s, m );
        console.log( 'α: %d, s: %d, m: %d, E(X;α,s,m): %d', alpha.toFixed( 4 ), s.toFixed( 4 ), m.toFixed( 4 ), y.toFixed( 4 ) );
    }

    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 © 2016-2021. The Stdlib Authors.

    Install

    npm i @stdlib/stats-base-dists-frechet-mean

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    14

    Version

    0.0.4

    License

    Apache-2.0

    Unpacked Size

    56.4 kB

    Total Files

    11

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