A high level arbitrary precision integer and rational arithmetic library wrapping imath.
The following example computes an approximation of pi using the Newton / Euler Convergence Transformation.
````rust use reckoner::{Integer, Rational};
fn factorial(v: &Integer) -> Integer { let mut accum = 1.into(); let mut f = v.clone();
while &f > &0 {
accum *= &f;
f -= 1;
}
accum
}
// Product of all odd integers up to the given value. fn odd_factorial(v: &Integer) -> Integer { let mut accum = 1.into(); let mut f = if v % 2 == 0 { v - 1 } else { v.clone() };
while &f > &0 {
accum *= &f;
f -= 2;
}
accum
}
//
// \frac{\pi}{2}
// = \sum_{k=0}^\infty\frac{k!}{(2k+1)!!}
// = \sum_{k=0}^{\infty} \cfrac {2^k k!^2}{(2k + 1)!}
// = 1+\frac{1}{3}\left(1+\frac{2}{5}\left(1+\frac{3}{7}\left(1+\cdots\right)\right)\right)
//
fn computepiapprox(iterations: u32) -> Rational {
2 * (0..iterations)
.map(Integer::from)
.map(|n| {
let numerator = factorial(&n);
let denominator = odd_factorial(&(2 * n + 1));
(numerator, denominator).into()
})
.sum::<Rational>()
} ````
See examples/ for more.
reckoner
A high level arbitrary precision arithmetic library supporting integer and rational numbers.
imath-sys
FFI bindings for imath.