Need private packages and team management tools?Check out npm Teams »

compute-euclidean-distance

1.0.0 • Public • Published

Euclidean Distance

NPM version Build Status Coverage Status Dependencies

Computes the Euclidean distance between two arrays.

The Euclidean distance is the straight line distance between two points in Euclidean space.

Euclidean distance formula

Installation

$ npm install compute-euclidean-distance

For use in the browser, use browserify.

Usage

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

euclidean( x, y[, accessor] )

Computes the Euclidean distance between two arrays.

var x = [ 2, 4, 5, 3, 8, 2 ],
    y = [ 3, 1, 5, -3, 7, 2 ];
 
var d = euclidean( x, y );
// returns ~6.86

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;
}
 
= euclidean( x, y, getValue );
// returns ~6.86

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 euclidean = require( 'compute-euclidean-distance' );
 
var x = new Array( 100 ),
    y = new Array( 100 );
 
for ( var i = 0; i < x.length; i++ ) {
    x[ i ] = Math.round( Math.random()*10 );
    y[ i ] = Math.round( Math.random()*10 );
}
 
console.log( euclidean( x, y ) );

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

$ node ./examples/index.js

References

  • Dahlquist, Germund and Bjorck, Ake. Numerical Methods in Scientific Computing.
  • Blue, James (1978) "A Portable Fortran Program To Find the Euclidean Norm of a Vector". ACM Transactions on Mathematical Software.
  • Higham, Nicholas J. Accuracy and Stability of Numerical Algorithms, Second Edition.

This module implements a one-pass algorithm proposed by S.J. Hammarling.

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. Athan Reines.

Install

npm i compute-euclidean-distance

DownloadsWeekly Downloads

180

Version

1.0.0

License

none

Last publish

Collaborators

  • avatar
  • avatar