compute-cosine-similarity
v1.1.0
Published
Computes the cosine similarity between two arrays.
Downloads
169,406
Readme
Cosine Similarity
Computes the cosine similarity between two arrays.
Cosine similarity defines vector similarity in terms of the angle separating two vectors.
Installation
$ npm install compute-cosine-similarity
For use in the browser, use browserify.
Usage
var similarity = require( 'compute-cosine-similarity' );
similarity( x, y[, accessor] )
Computes the cosine similarity between two arrays
.
var x = [ 5, 23, 2, 5, 9 ],
y = [ 3, 21, 2, 5, 14 ];
var s = similarity( x, y );
// returns ~0.975
For object arrays
, provide an accessor function
for accessing numeric
values.
var x = [
{'x':2},
{'x':4},
{'x':5}
];
var y = [
[1,3],
[2,1],
[3,5]
];
function getValue( d, i, j ) {
if ( j === 0 ) {
return d.x;
}
return d[ 1 ];
}
var s = similarity( x, y, getValue );
// returns ~0.882
The accessor function
is provided three arguments:
- d: current datum.
- i: current datum index.
- j: array index; e.g., array
x
has index0
, and arrayy
has index1
.
If provided empty arrays
, the function returns null
.
Examples
var similarity = require( 'compute-cosine-similarity' );
var x = new Array( 100 ),
y = new Array( 100 ),
s;
for ( var i = 0; i < x.length; i++ ) {
x[ i ] = Math.round( Math.random()*100 );
y[ i ] = Math.round( Math.random()*100 );
}
s = similarity( x, y );
console.log( s );
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
Copyright
Copyright © 2015. The Compute.io Authors. All rights reserved.