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:
extern crate num;
# #[cfg(all(feature = "bigint", feature="rational"))]
# mod test {
use num::FromPrimitive;
use num::bigint::BigInt;
use num::rational::{Ratio, BigRational};
# pub
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
}
# }
# #[cfg(not(all(feature = "bigint", feature="rational")))]
# mod test { pub fn approx_sqrt(n: u64, _: usize) -> u64 { n } }
# use test::approx_sqrt;
fn main() {
println!("{}", approx_sqrt(10, 4)); // prints 4057691201/1283082416
}