# [−][src]Crate num

A collection of numeric types and traits for Rust.

This includes new types for big integers, rationals, and complex numbers, new traits for generic programming on numeric properties like `Integer`, and generic range iterators.

## Example

This example uses the BigRational type and Newton's method to approximate a square root to arbitrary precision:

```
use num::FromPrimitive;
use num::bigint::BigInt;
use num::rational::{Ratio, BigRational};

fn approx_sqrt(number: u64, iterations: usize) -> BigRational {
let start: Ratio<BigInt> = Ratio::from_integer(FromPrimitive::from_u64(number).unwrap());
let mut approx = start.clone();

for _ in 0..iterations {
approx = (&approx + (&start / &approx)) /
Ratio::from_integer(FromPrimitive::from_u64(2).unwrap());
}

approx
}

fn main() {
println!("{}", approx_sqrt(10, 4)); // prints 4057691201/1283082416
}
```

## Compatibility

The `num` crate is tested for rustc 1.31 and greater.

## Modules

 bigint cast complex integer iter pow rational traits

## Structs

 BigInt A big signed integer type. BigUint A big unsigned integer type. Complex A complex number in Cartesian form.

## Traits

 Bounded Numbers which have upper and lower bounds CheckedAdd Performs addition that returns `None` instead of wrapping around on overflow. CheckedDiv Performs division that returns `None` instead of panicking on division by zero and instead of wrapping around on underflow and overflow. CheckedMul Performs multiplication that returns `None` instead of wrapping around on underflow or overflow. CheckedSub Performs subtraction that returns `None` instead of wrapping around on underflow. Float Generic trait for floating point numbers FromPrimitive A generic trait for converting a number to a value. Integer Num The base trait for numeric types, covering `0` and `1` values, comparisons, basic numeric operations, and string conversion. NumCast An interface for casting between machine scalars. One Defines a multiplicative identity element for `Self`. PrimInt Generic trait for primitive integers. Saturating Saturating math operations. Deprecated, use `SaturatingAdd`, `SaturatingSub` and `SaturatingMul` instead. Signed Useful functions for signed numbers (i.e. numbers that can be negative). ToPrimitive A generic trait for converting a value to a number. Unsigned A trait for values which cannot be negative Zero Defines an additive identity element for `Self`.

## Functions

 abs Computes the absolute value. abs_sub The positive difference of two numbers. cast Cast from one machine scalar to another. checked_pow Raises a value to the power of exp, returning `None` if an overflow occurred. clamp A value bounded by a minimum and a maximum one Returns the multiplicative identity, `1`. pow Raises a value to the power of exp, using exponentiation by squaring. range Returns an iterator over the given range [start, stop) (that is, starting at start (inclusive), and ending at stop (exclusive)). range_inclusive Return an iterator over the range [start, stop] range_step Return an iterator over the range [start, stop) by `step`. It handles overflow by stopping. range_step_inclusive Return an iterator over the range [start, stop] by `step`. It handles overflow by stopping. signum Returns the sign of the number. zero Returns the additive identity, `0`.

## Type Definitions

 BigRational Alias for arbitrary precision rationals. Rational Alias for a `Ratio` of machine-sized integers.