vyre 0.4.0

GPU compute intermediate representation with a standard operation library
Documentation 
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use crate::ops::string_similarity::validation::{validate_input, SimilarityError};

// CPU reference kernel for `string_similarity.simhash64`.



pub const FNV_OFFSET: u64 = 0xcbf2_9ce4_8422_2325;

pub const FNV_PRIME: u64 = 0x0000_0100_0000_01b3;

pub const DEFAULT_GRAM: usize = 4;

/// Compute a 64-bit SimHash over overlapping 4-byte shingles.
///
/// Inputs shorter than four bytes are hashed as one whole-input shingle.
///
/// # Errors
///
/// Returns `Fix: ...` when the input exceeds the documented cap.
pub fn simhash64(input: &[u8]) -> Result<u64, SimilarityError> {
    validate_input("input", input)?;
    let mut weights = [0i32; 64];
    if input.is_empty() {
        return Ok(0);
    }
    if input.len() < DEFAULT_GRAM {
        add_hash(&mut weights, fnv1a64(input));
    } else {
        for gram in input.windows(DEFAULT_GRAM) {
            add_hash(&mut weights, fnv1a64(gram));
        }
    }
    let mut out = 0u64;
    for (bit, &weight) in weights.iter().enumerate() {
        if weight >= 0 {
            out |= 1u64 << bit;
        }
    }
    Ok(out)
}

pub fn add_hash(weights: &mut [i32; 64], hash: u64) {
    for (bit, weight) in weights.iter_mut().enumerate() {
        if ((hash >> bit) & 1) == 1 {
            *weight += 1;
        } else {
            *weight -= 1;
        }
    }
}

pub fn fnv1a64(input: &[u8]) -> u64 {
    input.iter().fold(FNV_OFFSET, |hash, &byte| {
        (hash ^ u64::from(byte)).wrapping_mul(FNV_PRIME)
    })
}

// Backend-specific lowering marker.

// WGSL lowering source for `string_similarity.simhash64`.

/// FNV-1a shingle SimHash kernel used by GPU parity tests and intrinsic dispatch.
pub const WGSL: &str = concat!(
    include_str!("../wgsl/common_params.wgsl"),
    "\n",
    include_str!("wgsl/simhash64.wgsl"),
);