Fix D-inf flow direction odd facet decomposition (Tarboton 1997)#1005
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brendancol merged 3 commits intomasterfrom Mar 14, 2026
Merged
Fix D-inf flow direction odd facet decomposition (Tarboton 1997)#1005brendancol merged 3 commits intomasterfrom
brendancol merged 3 commits intomasterfrom
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Odd facets (1,3,5,7) incorrectly used consecutive CCW neighbor pairs (e.g. facet 1: e1=NE, e2=N) with diagonal-based d1 distances. Tarboton requires e1=cardinal, e2=diagonal with alternating angle sign (e.g. facet 1: e1=N, e2=NE, angle=pi/2-r). Even facets were already correct. Fixed both CPU and GPU kernels.
- Increase GPU scanline fill MAX_ISECT from 512 to 2048 to handle dense polygon inputs (1000+ irregular polygons would silently drop edges, causing wrong pixel values and missing coverage) - Add host-side warning when active edge count exceeds the GPU limit - Vectorize _classify_geometries using shapely 2.0 array ops instead of per-geometry Python calls (178x faster for the classification step) - Defer bounds computation in _parse_input so callers who supply explicit bounds skip the unnecessary bbox scan - Add cross-library rasterizer benchmark (benchmarks/rasterizer_benchmarks.py) covering 10 geometry types with consistency checks and markdown output
…ology API - Move D-inf flow accumulation from flow_accumulation.py into flow_accumulation_dinf.py with its own test file - Update basin, watershed, stream_order, and stream_order_mfd to use D8 flow direction consistently - Add flow_accumulation_dinf to public API and docs - Simplify flow_accumulation.py to D8-only logic
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Summary
_cpu) and GPU (_gpu) kernels.test_odd_facet_1_tarboton,test_odd_facet_7_tarboton) and a full-grid comparison against a pure-Python reference Tarboton (test_reference_tarboton_agreement).Test plan
test_flow_direction_dinf.pypass (numpy, dask, cupy, dask+cupy)