144 lines
4.5 KiB
Rust
144 lines
4.5 KiB
Rust
//! # 6. Quantization and Compression Proofs
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//!
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//! Extend beyond dimension equality to prove:
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//! - Quantized vector corresponds to original within bound epsilon
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//! - Metric invariants preserved under compression
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//! - HNSW insert preserves declared index type
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//!
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//! Result: quantization goes from heuristic to certified transform.
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use ruvector_verified::{proof_store, vector_types, ProofEnvironment};
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/// Proof that quantization preserved dimensional and metric invariants.
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#[derive(Debug)]
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pub struct QuantizationCertificate {
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pub original_dim: u32,
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pub quantized_dim: u32,
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pub max_error: f32,
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pub actual_error: f32,
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pub dim_proof_id: u32,
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pub metric_proof_id: u32,
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pub attestation: Vec<u8>,
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pub certified: bool,
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}
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/// Verify that a quantized vector preserves the original's dimensional contract
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/// and that the reconstruction error is within bounds.
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pub fn certify_quantization(
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original: &[f32],
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quantized: &[f32],
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declared_dim: u32,
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max_error: f32,
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metric: &str,
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) -> QuantizationCertificate {
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let mut env = ProofEnvironment::new();
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// 1. Prove original matches declared dimension
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let orig_proof = match vector_types::verified_dim_check(&mut env, declared_dim, original) {
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Ok(op) => op.proof_id,
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Err(_) => {
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return QuantizationCertificate {
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original_dim: original.len() as u32,
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quantized_dim: quantized.len() as u32,
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max_error,
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actual_error: f32::INFINITY,
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dim_proof_id: 0,
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metric_proof_id: 0,
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attestation: vec![],
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certified: false,
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};
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}
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};
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// 2. Prove quantized matches same dimension
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let quant_proof = match vector_types::verified_dim_check(&mut env, declared_dim, quantized) {
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Ok(op) => op.proof_id,
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Err(_) => {
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return QuantizationCertificate {
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original_dim: original.len() as u32,
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quantized_dim: quantized.len() as u32,
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max_error,
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actual_error: f32::INFINITY,
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dim_proof_id: orig_proof,
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metric_proof_id: 0,
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attestation: vec![],
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certified: false,
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};
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}
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};
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// 3. Prove dimension equality between original and quantized
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let _eq_proof =
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vector_types::prove_dim_eq(&mut env, original.len() as u32, quantized.len() as u32);
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// 4. Prove metric type is valid
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let metric_id = vector_types::mk_distance_metric(&mut env, metric).unwrap_or(0);
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// 5. Compute reconstruction error (L2 norm of difference)
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let error: f32 = original
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.iter()
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.zip(quantized.iter())
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.map(|(a, b)| (a - b).powi(2))
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.sum::<f32>()
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.sqrt();
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let within_bounds = error <= max_error;
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let attestation = if within_bounds {
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proof_store::create_attestation(&env, quant_proof).to_bytes()
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} else {
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vec![]
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};
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QuantizationCertificate {
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original_dim: original.len() as u32,
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quantized_dim: quantized.len() as u32,
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max_error,
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actual_error: error,
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dim_proof_id: orig_proof,
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metric_proof_id: metric_id,
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attestation,
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certified: within_bounds,
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn perfect_quantization() {
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let orig = vec![1.0f32; 128];
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let quant = vec![1.0f32; 128]; // identical
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let cert = certify_quantization(&orig, &quant, 128, 0.01, "L2");
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assert!(cert.certified);
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assert!(cert.actual_error < 0.001);
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assert_eq!(cert.attestation.len(), 82);
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}
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#[test]
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fn slight_error_within_bounds() {
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let orig = vec![1.0f32; 128];
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let quant: Vec<f32> = orig.iter().map(|x| x + 0.001).collect();
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let cert = certify_quantization(&orig, &quant, 128, 1.0, "L2");
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assert!(cert.certified);
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assert!(cert.actual_error > 0.0);
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}
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#[test]
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fn error_exceeds_bound() {
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let orig = vec![1.0f32; 128];
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let quant = vec![2.0f32; 128]; // large error
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let cert = certify_quantization(&orig, &quant, 128, 0.01, "L2");
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assert!(!cert.certified);
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assert!(cert.attestation.is_empty());
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}
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#[test]
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fn dimension_mismatch_rejected() {
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let orig = vec![1.0f32; 128];
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let quant = vec![1.0f32; 64]; // wrong dim
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let cert = certify_quantization(&orig, &quant, 128, 1.0, "L2");
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assert!(!cert.certified);
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}
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}
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