big-rat
=======
Arbitrary precision rational number arithmetic

[![build status](https://secure.travis-ci.org/rat-nest/big-rat.png)](http://travis-ci.org/rat-nest/big-rat)

# Example

#### Program

```javascript
var rat = require('big-rat')

//Construct a pair of rational numbers;
//   a = 1/10
//   b = 2/10
var a = rat(1, 10)
var b = rat(2, 10)

//Compute their sum
var add = require('big-rat/add')
var c = add(a, b)

//Print out sum
var toString = require('big-rat/to-string')
console.log('a+b=', toString(c))

//And also convert to a number
var toFloat = require('big-rat/to-float')
console.log('exact rational result:', toFloat(c))

//For comparison, here is the same computation performed with floats
var x = 0.1
var y = 0.2
console.log('approximate float result:', x + y)
```

#### Output

```
a+b= 3/10
exact rational result: 0.3
approximate float result: 0.30000000000000004
```

# Install

```
npm i big-rat
```

# API

#### `var r = require('big-rat')(n[, d])`
Constructs a rational number as the quotient n/d

* `n` is the numerator.  Can be a float, string, bignum or rational
* `d` is the denominator (optional, default `1`)

**Returns** A rational number

#### `var f = require('big-rat/to-float')(r)`

**Returns** The closest floating point number to `r`

#### `var s = require('big-rat/to-string')(r)`

**Returns** A string representing the big rat `r`

#### `var b = require('big-rat/is-rat')(r)`

**Returns** `true` if `r` is a big rat

#### `var c = require('big-rat/add')(a, b)`

**Returns** `a+b`

#### `var c = require('big-rat/sub')(a, b)`

**Returns** `a-b`

#### `var c = require('big-rat/mul')(a, b)`

**Returns** `a*b`

#### `var c = require('big-rat/div')(a, b)`

**Returns** `a/b`

#### `var c = require('big-rat/neg')(a)`

**Returns** `-a`

#### `var c = require('big-rat/recip')(a)`

**Returns** `1/a`

#### `var c = require('big-rat/sign')(a)`

**Returns** One of the following values:

* `-1` if `a<0`
* `0` if `a=0`
* `+1` if `a>0`

#### `var c = require('big-rat/abs')(a)`

**Returns** `|a|`

#### `var c = require('big-rat/min')(a, b)`

**Returns** `min(a,b)`

#### `var c = require('big-rat/max')(a, b)`

**Returns** `max(a,b)`

#### `var c = require('big-rat/equals')(a, b)`

**Returns** `true` if `a=b`, `false` otherwise

#### `var c = require('big-rat/cmp')(a, b)`

**Returns**

* `-1` if `a<b`
* `0` if `a=b`
* `+1` if `a>b`

# License

(c) 2015 MIT License