nalgebra/src/base/helper.rs

#[cfg(feature = "arbitrary")]
use quickcheck::{Arbitrary, Gen};
use rand::{Rand, Rng};

/// Simple helper function for rejection sampling
#[cfg(feature = "arbitrary")]
#[doc(hidden)]
#[inline]
pub fn reject<G: Gen, F: FnMut(&T) -> bool, T: Arbitrary>(g: &mut G, f: F) -> T {
    use std::iter;
    iter::repeat(())
        .map(|_| Arbitrary::arbitrary(g))
        .find(f)
        .unwrap()
}

#[doc(hidden)]
#[inline]
pub fn reject_rand<G: Rng, F: FnMut(&T) -> bool, T: Rand>(g: &mut G, f: F) -> T {
    use std::iter;
    iter::repeat(()).map(|_| Rand::rand(g)).find(f).unwrap()
}