perf: spatial hash grid, sqrt elimination, GC-free hot path#1
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OldCrow wants to merge 3 commits intotjards:masterfrom
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perf: spatial hash grid, sqrt elimination, GC-free hot path#1OldCrow wants to merge 3 commits intotjards:masterfrom
OldCrow wants to merge 3 commits intotjards:masterfrom
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Reduces per-frame complexity from O(n^2) to O(n) for bounded-density interactions, extending usable agent count from ~200 to 2000+. Performance: - Spatial hash grid (spatial-grid.js): O(1) neighbor queries replace O(n) full scans in herd and shepherd update loops - Squared distance comparisons: range checks avoid sqrt, only computed when normalizing direction vectors - GC pressure eliminated: pre-allocated limitMagnitude output, removed per-frame array spreads and precomputeOtherShepherds allocation Bug fixes: - Shepherd closest-herd-member search uses full list (not grid) to handle wrap-around boundaries correctly Additions: - .gitignore - OPTIMIZATION.md: problem statement, methodology, per-file changes, design decisions (spatial hash vs KD-tree, GC avoidance, batched rendering), measured results, future work - FPS counter overlay (dark background for visibility on light canvas) Measured results (144Hz monitor): - 144 FPS sustained to 1100 agents (vsync-capped) - ~100 FPS at 2100 agents (est. ~7x over original O(n^2)) No external dependencies. All vanilla JavaScript. Co-Authored-By: Oz <oz-agent@warp.dev>
Cantor pairing is only bijective for non-negative integers. query() could produce negative cell coordinates for agents near the top/left canvas edges, causing hash collisions with positive cells. This returned duplicate agents in results, multi-counting their forces. Clamp minCx/minCy to 0 since agents always wrap to non-negative positions—negative cells are guaranteed empty. Co-Authored-By: Oz <oz-agent@warp.dev>
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Pushed a bugfix in 5637394: the spatial grid's Cantor pairing hash is only bijective for non-negative integers, but Fix: clamp |
Co-Authored-By: Oz <oz-agent@warp.dev>
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Summary
Reduces per-frame complexity from O(n²) to O(n) for bounded-density interactions, extending usable agent count from ~200 to 2000+ at 60fps.
Changes
spatial-grid.js): O(1) neighbor queries replace O(n) full scans in herd and shepherd update loopsMath.sqrt, only computed when normalizing direction vectorslimitMagnitudeIntooutput, removed per-frameprecomputeOtherShepherds()array allocation and[...herd.members]spread.gitignoreandOPTIMIZATION.md: documentation covering methodology, design decisions, measured results, and future workBug Fix
Shepherd closest-herd-member search uses full list scan (not spatial grid) to correctly handle wrap-around boundaries.
Measured Results (144Hz monitor)
No external dependencies. All vanilla JavaScript.
Co-Authored-By: Oz oz-agent@warp.dev