nextafter

Returns the next representable double-precision floating-point number after x toward y.

Installation

$ npm install math-float64-nextafter

Usage

var nextafter = require( 'math-float64-nextafter' );

nextafter( x, y )

Returns the next representable double-precision floating-point number after x toward y.

var z = nextafter( 1, 100 )
// returns 1.0000000000000002
 
z = nextafter( 1, 0 );
// returns 0.9999999999999999
 
z = nextafter( -9007199254740992, -1e300 );
// returns -9007199254740994

If x equals y, the function returns y, ensuring consistent behavior around zero.

var z = nextafter( +0.0, -0.0 );
// returns -0.0
 
z = nextafter( -0.0, +0.0 );
// returns +0.0

If either x or y is NaN, the function returns NaN.

var z = nextafter( NaN, 5.0 );
// returns NaN
 
z = nextafter( 5.0, NaN );
// returns NaN
 
z = nextafter( NaN, NaN );
// returns NaN

Examples

var PINF = require( 'const-pinf-float64' );
var NINF = require( 'const-ninf-float64' );
var nextafter = require( 'math-float64-nextafter' );
 
var x;
var y;
var z;
var i;
 
for ( i = 0; i < 100; i++ ) {
    x = Math.random()*1e6 - 5e5;
    if ( Math.random() < 0.5 ) {
        y = NINF;
    } else {
        y = PINF;
    }
    z = nextafter( x, y );
    console.log( 'x = %d, y = %d. nextafter(x,y) => %d', x, y, z );
}

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.