compute-chebyshev-distance

    1.0.2 • Public • Published

    Chebyshev Distance

    NPM version Build Status Coverage Status Dependencies

    Computes the Chebyshev distance between two arrays.

    The Chebyshev distance is a metric defined on a vector space where the distance between two vectors is the greatest difference along any coordinate dimension.

    Chebyshev distance formula

    Installation

    $ npm install compute-chebyshev-distance

    For use in the browser, use browserify.

    Usage

    var chebyshev = require( 'compute-chebyshev-distance' );

    chebyshev( x, y[, accessor] )

    Computes the Chebyshev distance between two arrays.

    var x = [ 2, 4, 5, 3, 8, 2 ],
        y = [ 3, 1, 5, -3, 7, 2 ];
     
    var d = chebyshev( x, y );
    // returns 6

    For object arrays, provide an accessor function for accessing numeric values.

    var x, y, d;
     
    = [
        [1,2],
        [2,4],
        [3,5],
        [4,3],
        [5,8],
        [6,2]
    ];
     
    = [
        {'y':3},
        {'y':1},
        {'y':5},
        {'y':-3},
        {'y':7},
        {'y':2}
    ];
     
    function getValue( d, i, j ) {
        if ( j === 0 ) {
            return d[ 1 ];
        }
        return d.y;
    }
     
    var d = chebyshev( x, y, getValue );
    // returns 6

    The accessor function is provided three arguments:

    • d: current datum.
    • i: current datum index.
    • j: array index; e.g., array x has index 0 and array y has index 1.

    If provided empty arrays, the function returns null.

    Examples

    var chebyshev = require( 'compute-chebyshev-distance' );
     
    var x = new Array( 100 ),
        y = new Array( 100 );
     
    for ( var i = 0; i < x.length; i++ ) {
        x[ i ] = Math.round( Math.random()*100 );
        y[ i ] = Math.round( Math.random()*100 );
    }
     
    console.log( chebyshev( x, y ) );

    To run the example code from the top-level application directory,

    $ node ./examples/index.js

    Tests

    Unit

    Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:

    $ make test

    All new feature development should have corresponding unit tests to validate correct functionality.

    Test Coverage

    This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

    $ make test-cov

    Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

    $ make view-cov

    License

    MIT license.

    Copyright

    Copyright © 2015. Philipp Burckhardt.

    Install

    npm i compute-chebyshev-distance

    DownloadsWeekly Downloads

    57

    Version

    1.0.2

    License

    none

    Last publish

    Collaborators

    • planeshifter
    • kgryte