Computes the L2 norm (Euclidean norm) of an array of values.
npm install compute-l2normL2 norm
===
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> Computes the L2 norm (Euclidean norm)) of an array.
`` bash`
$ npm install compute-l2norm
For use in the browser, use browserify.
` javascript`
var l2norm = require( 'compute-l2norm' );
#### l2norm( arr[, accessor] )
Computes the _L2_ norm (Euclidean norm) of an array.
` javascript
var data = [ 2, 7, 3, -3, 9 ];
var norm = l2norm( data );
// returns ~12.3288
`
For object arrays, provide an accessor function for accessing array values.
` javascript
var data = [
['beep', 3],
['boop', 4]
];
function getValue( d, i ) {
return d[ 1 ];
}
var norm = l2norm( data, getValue );
// returns 5
`
If provided an empty array, the function returns null.
` javascript
var l2norm = require( 'compute-l2norm' );
var data = new Array( 1000 );
for ( var i = 0; i < data.length; i++ ) {
data[ i ] = Math.random() * 100;
}
console.log( l2norm( data ) );
`
To run the example code from the top-level application directory,
` bash`
$ node ./examples/index.js
- 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.
Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:
` bash`
$ make test
All new feature development should have corresponding unit tests to validate correct functionality.
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:
` bash`
$ make test-cov
Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,
` bash``
$ make view-cov
---
Copyright © 2014-2015. Athan Reines.
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