Astro-float (astronomically large floating point numbers) is a library that implements arbitrary precision floating point numbers purely in Rust.
The library implements the basic operations and functions. It uses classical algorithms such as Karatsuba, Toom-3, Schönhage-Strassen algorithm, etc.
Compute Pi with precision of 1024 bit:
``` rust use astrofloat::BigFloatNumber; use astrofloat::PI; use astrofloat::RoundingMode; use astrofloat::Radix; use astro_float::Error;
// Rounding of all operations let rm = RoundingMode::ToEven;
// Compute pi: pi = 6*arctan(1/sqrt(3)) let six = BigFloatNumber::fromword(6, 1).unwrap(); let three = BigFloatNumber::parse("3.0", Radix::Dec, 1024+8, rm).unwrap(); // +8 bits of precision to cover error let mut pi = six.mul(&three.sqrt(rm).unwrap().reciprocal(rm).unwrap().atan(rm).unwrap(), rm).unwrap(); pi.setprecision(1024, rm).unwrap(); let mut epsilon = BigFloatNumber::fromword(1, 1).unwrap(); epsilon.setexponent(-1021);
// Use library's constant for verifying the result
let pilib = PI.with(|v| -> Result
// Compare computed constant with library's constant assert!(pi.sub(&pi_lib, rm).unwrap().abs().unwrap().cmp(&epsilon) <= 0);
// Print computed result as decimal number. let s = pi.format(Radix::Dec, rm).unwrap(); println!("{}", s);
// output: 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848111745028410270193852110555964462294895493038196442881097566593344612847564823378678316527120190914564856692346034861045432664821339360726024914127372458698858e+0 ```
The library is still young and may lack some features or contain bugs. Issues for these or other cases can be opened here: https://github.com/stencillogic/astro-float/issues