Function next_pow2

nodedb-codec/src/vector_quant/rabitq.rs:56–62

(n: usize)

/// Next power-of-two ≥ `n`, returning `n` itself if already pow2.
#[inline]
fn next_pow2(n: usize) -> usize {
    if n.is_power_of_two() {
        n
    } else {
        n.next_power_of_two()
    }
}

/// In-place Walsh-Hadamard Transform of a power-of-2 length slice.
/// O(N log N) butterfly. Does not normalise by 1/√N (sign-only code