https://github.com/mikolalysenko/two-product

Multiplies two floating point numbers together, giving an increasing nonoverlapping sequence
https://github.com/mikolalysenko/two-product

Last synced: about 2 months ago
JSON representation

Multiplies two floating point numbers together, giving an increasing nonoverlapping sequence

• Host: GitHub
• URL: https://github.com/mikolalysenko/two-product
• Owner: mikolalysenko
• License: mit
• Created: 2013-09-18T18:00:06.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2014-05-28T17:25:13.000Z (over 10 years ago)
• Last Synced: 2024-10-20T14:27:13.598Z (2 months ago)
• Language: JavaScript
• Size: 199 KB
• Stars: 4
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
two-product

===========

Computes the product of two floating point numbers as a 2-term nonoverlapping increasing sequence.

[![testling badge](https://ci.testling.com/mikolalysenko/two-product.png)](https://ci.testling.com/mikolalysenko/two-product)

[![build status](https://secure.travis-ci.org/mikolalysenko/two-product.png)](http://travis-ci.org/mikolalysenko/two-product)

## Install

```

npm install two-product

```

		

## Example

```javascript

var twoProduct = require("two-product")

console.log(twoProduct(1 + Math.pow(2, -52), Math.pow(2, 52) + 1))

```

Output:

```javascript

[ 2.220446049250313e-16, 4503599627370498 ]

```

## API

### `require("two-product")(a, b[, result])`

Multiplies `a` and `b` and returns the product as a non-overlapping sequence.  `result` is an optional length 2 array that stores the result.

* `a` is a number

* `b` is a number

* `result` is an optional length 2 array that gets the result of multiplying `a` and `b`

**Returns** A length 2 array representing the product of `a` and `b` as an expansion.  The first entry is the lower order bits, and the second entry is the upper order bits.

**Note** This algorithm does not work correctly with denormalized numbers.

## Credits

JavaScript implementation (c) 2013-2014 Mikola Lysenko.  Based on ideas from Jonathan Shewchuk's [robust adaptive geometric predicates](http://www.cs.cmu.edu/~quake/robust.html).