recern-vector 0.0.2

A single-file, embedded, inspectable vector database
Documentation 
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/// SplitMix64: tiny, fast and deterministic. Its state is persisted with each
/// collection so that index construction is reproducible across sessions.
#[derive(Clone, Debug)]
pub(crate) struct SplitMix64 {
    pub(crate) state: u64,
}

impl SplitMix64 {
    pub(crate) fn new(seed: u64) -> Self {
        Self { state: seed }
    }

    pub(crate) fn next_u64(&mut self) -> u64 {
        self.state = self.state.wrapping_add(0x9E37_79B9_7F4A_7C15);
        let mut z = self.state;
        z = (z ^ (z >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
        z = (z ^ (z >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
        z ^ (z >> 31)
    }

    /// Uniform sample in `(0, 1]`.
    pub(crate) fn next_f64(&mut self) -> f64 {
        ((self.next_u64() >> 11) as f64 + 1.0) / (1u64 << 53) as f64
    }

    /// Uniform integer in `0..n`. `n` must be non-zero.
    pub(crate) fn below(&mut self, n: usize) -> usize {
        (self.next_u64() % n as u64) as usize
    }
}