← [b]ack

hello world

2026-10-25

first post.

flow

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fn fast_inv_sqrt(x: f32) -> f32 {
    let y = f32::from_bits(0x5f37_59df - (x.to_bits() >> 1));
    y * (1.5 - 0.5 * x * y * y)
}

fn fast_sqrt(x: f32) -> f32 {
    x * fast_inv_sqrt(x)
}

fn main() {
    for x in [2.0, 9.0, 1e6] {
        println!("{x}: {} vs {}", fast_sqrt(x), x.sqrt());
    }
}