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-Cook, Schönhage-Strassen algorithm, and others.
The library can work without the standard library provided there is a memory allocator.
## Usage
Below is an example of using the library.
For more information please refer to the library documentation: https://docs.rs/astro-float/latest/astro_float/
Calculate Pi with 1024 bit precision:
``` rust
use astro_float::BigFloat;
use astro_float::Consts;
use astro_float::RoundingMode;
// Precision with some space for error.
let p = 1024 + 8;
// Rounding of all operations
let rm = RoundingMode::ToEven;
// Initialize mathematical constants cache
let mut cc = Consts::new().unwrap();
// Compute pi: pi = 6*arctan(1/sqrt(3))
let six = BigFloat::from_word(6, 1);
let three = BigFloat::from_word(3, p);
let n = three.sqrt(p, rm);
let n = n.reciprocal(p, rm);
let n = n.atan(p, rm, &mut cc);
let mut pi = six.mul(&n, p, rm);
// Reduce precision to 1024
pi.set_precision(1024, rm).expect("Precision updated");
// Use library's constant for verifying the result
let pi_lib = cc.pi(1024, rm);
// Compare computed constant with library's constant
assert_eq!(pi.cmp(&pi_lib), Some(0));
// Print using decimal radix.
println!("{}", pi);
```
## Correctness
Currently, arithmetic operations (add, sub, mul, div, rem), rounding, and constants produce identical results with [rug](https://crates.io/crates/rug) (MPFR), while other operations produce results that may differ by 1 ulp.
The source code contains corresponding [integration tests](https://github.com/stencillogic/astro-float/tree/main/tests).
## Performance
Benchmark can be found here: https://github.com/stencillogic/bigfloat-bench.
## Roadmap
Future improvements include the implementation of faster mathematical function algorithms for arguments with large precision, such as AGM implementation for calculating the logarithm, and faster trigonometric functions.
## Contributing
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