Verify correctness of PR #196 AVX2 distance computation refactoring #207
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PR #196 refactored AVX2 distance computations to use
generic_simd_op()with operator structs, replacing ~500 lines of per-type-combination SIMD code with ~200 lines of unified infrastructure. This raised concerns about whether the carefully-crafted type-specific implementations ({float,float}, {float,fp16}, {float,int8}, {int8,int8}, etc.) were correctly preserved.Verification Methodology
Line-by-line analysis: Compared intrinsic sequences for all type combinations (Float×Float, Float×Int8, Int8×Int8, UInt8×UInt8, Float16×Float16, Float×Float16). Confirmed:
Comprehensive testing: Added
compute_ops_verification.cppwith 12,000+ assertions covering:Performance analysis: Core intrinsics identical. Improvements from 4-way unrolling (32 vs 8 elements/iter) and vectorized epilogue.
Key Findings
Numerical differences < 1×10⁻⁴ due to accumulation order (4-way unroll vs sequential). Expected and acceptable.
Documentation
pr196_analysis.md: Detailed intrinsic-level comparisonpr196_final_report.md: Complete verification reportVERIFICATION_SUMMARY.md: Executive summaryVerdict
PR #196 refactoring is correct. All type combinations produce correct results. Performance maintained or improved.
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