Crate num_bigfloat

Expand description

Multiple precision floating point numbers implemented purely in Rust. Number has fixed-size mantissa and exponent, but increased precision compared to f32 or f64 values.

Number characteristics:

Name	Value
Decimal positions in mantissa	40
Exponent minimum value	-128
Exponent maximum value	127

Examples

use num_bigfloat::BigFloat;
use num_bigfloat::ONE;
use num_bigfloat::PI;
 
// compute pi: pi = 6*arctan(1/sqrt(3))
let six: BigFloat = 6.0.into(); // note: conversion from f64,f32 are not loss-less.
let three: BigFloat = BigFloat::parse("3.0").unwrap();
let pi = six * (ONE / three.sqrt()).atan();
let epsilon = 1.0e-38.into();
 
assert!((pi - PI).abs() < epsilon);
 
println!("{}", pi);
// output: 3.141592653589793238462643383279502884196e-39

Performance

The fixed-size mantissa allowed the introduction of precomputed tables to speed up most calculations. With regard to anything else, the implementation is straightforward.