Floating Point Raw ULP comparison

ulps.rs

//! Taken from Stack overflow: ttps://stackoverflow.com/a/17871376/5713037


fn diff_ulps(a: f64, b: f64) -> u64 {
    (raw_ulps(a) as i64).wrapping_sub(raw_ulps(b) as i64).abs() as u64
}
fn raw_ulps(f: f64) -> u64 {
    assert!(!f.is_nan());
    let b: u64 = f.to_bits();
    const TOP: u64 = 0x8000_0000_0000_0000;
    let b = if (b as i64) < 0 { TOP.wrapping_sub(b) } else { b };
    assert!((b as i64) >= 0);
    b
}

// original:
/*

public static boolean compareDoubleEquals(double expected, double actual, long maxUlps) {
    long expectedBits = Double.doubleToLongBits(expected) < 0 ? 0x8000000000000000L - Double.doubleToLongBits(expected) : Double.doubleToLongBits(expected);
    long actualBits = Double.doubleToLongBits(actual) < 0 ? 0x8000000000000000L - Double.doubleToLongBits(actual) : Double.doubleToLongBits(actual);
    long difference = expectedBits > actualBits ? expectedBits - actualBits : actualBits - expectedBits;

    return !Double.isNaN(expected) && !Double.isNaN(actual) && difference <= maxUlps;
}
*/