betaln

Natural logarithm of the Beta function.

This function evaluates the natural logarithm of the Beta function, defined as follows:

In here, Γ denotes the Gamma function.

Installation

$ npm install math-betaln

Usage

var betaln = require( 'math-betaln' );

betaln( x, y )

Evaluates the natural logarithm of the Beta function.

var val = betaln( 0, 0 );
// returns +Infinity
 
val = betaln( 0.001, 0.001 );
// returns ~7.601
 
val = betaln( -1, 2 );
// return NaN
 
val = betaln( 2, 1 );
// returns ~-1.099
 
val = betaln( 4, 1 );
// returns ~-1.386

Examples

var betaln = require( 'math-betaln' );
 
for ( var x = 0; x < 5; x++ ) {
    for ( var y = 5; y > 0; y-- ) {
        console.log( 'x: %d, \t y: %d, \t f(x,y): %d', x, y, betaln( x, y ) );
    }
}
 

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

$ node ./examples/index.js

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Tests

Unit

This repository uses tape for unit tests. 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

Browser Support

This repository uses Testling for browser testing. To run the tests in a (headless) local web browser, execute the following command in the top-level application directory:

$ make test-browsers

To view the tests in a local web browser,

$ make view-browser-tests

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License

MIT license.

Copyright

Copyright © 2016. The Compute.io Authors.