v1.0.55
Endgame tablebase correctness
- Tablebase scores now remain below the engine mate band.
- Positions with castling rights bypass Syzygy probing.
- All-losing tablebase roots now select the best available DTZ move.
- In-search WDL probing remains a separate future enhancement.
Faster NNUE evaluation on AVX2
The 512-wide NNUE forward pass now has a dedicated AVX2 kernel while retaining the portable fallback.
- NNUE forward-pass microbenchmark: approximately 27% faster on the tested AVX2 processor.
- Fixed-affinity depth-12 engine benchmark: 2.411% faster ±0.332% paired 95% CI.
- Search topology and the 3,027,236-node deterministic signature were unchanged.
Use an AVX2 binary on supported x86-64 CPUs. Portable binaries remain available for other systems.
Search correctness and time management
- Singular-verification searches no longer use forward-pruning shortcuts that can invalidate the excluded-move result.
- Unexpectedly expensive timed iterations stop at the maximum soft-budget ceiling instead of consuming the hard-time reserve.
- Optional diagnostics preserve and report the first search stop cause.
Validation
- Full optimized suite: 209 passed, 0 failed, 3 ignored.
- Formatting and Clippy passed.
- Six platform binaries built successfully.
- UCI reports Rusty Rival 1.0.55.
Full changelog: v1.0.54...v1.0.55