Provides a method to compute a moving arithmetic mean incrementally.
npm install compute-incrmmeanincrmmean
===
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> Provides a method to compute a moving arithmetic mean incrementally.
`` bash`
$ npm install compute-incrmmean
For use in the browser, use browserify.
` javascript`
var incrmmean = require( 'compute-incrmmean' );
#### incrmmean( window )
Returns an initialized method to compute a moving arithmetic mean incrementally. window sets the window size, i.e., the number of values over which to compute a moving mean.
` javascript`
var mmean = incrmmean( 3 );
#### mmean( [value] )
If provided a value, the method updates and returns the mean of the current window. If not provided a value, the method returns the current mean.
` javascript
var mu;
// Filling window...
mu = mmean( 2 );
// mean is 2
mmean( 3 );
// mean is 2.5
mmean( 2 );
// mean is 2.33...
// Window starts sliding...
mmean( -2 );
// mean is 1
mmean( 9 );
// mean is 3
mu = mmean();
// returns 3
`
1. If values have not yet been provided to mmean, mmean returns null.W-1
1. The first returned means will have less statistical support than subsequent moving means, as W values are needed to fill the window buffer. Until the window is full, the mean returned equals the arithmetic mean of all values provided thus far.
The use case for this module differs from the conventional vector implementation and the stream implementation. Namely, this module decouples the act of updating the moving mean from the act of consuming the moving mean.
` javascript
var incrmmean = require( 'compute-incrmmean' );
// Initialize a method to calculate the moving mean incrementally:
var mmean = incrmmean( 5 ),
mu;
// Simulate some data...
for ( var i = 0; i < 1000; i++ ) {
mu = mmean( Math.random()*100 );
console.log( mu );
}
mu = mmean();
console.log( mu );
`
To run the example code from the top-level application directory,
` bash`
$ node ./examples/index.js
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. The Compute.io Authors.
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[npm-url]: https://npmjs.org/package/compute-incrmmean
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[travis-url]: https://travis-ci.org/compute-io/incrmmean
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[dependencies-url]: https://david-dm.org/compute-io/incrmmean
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[dev-dependencies-url]: https://david-dm.org/dev/compute-io/incrmmean
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[github-issues-url]: https://github.com/compute-io/incrmmean/issues