Guard watershed_mfd() against unbounded memory allocations (#1339)#1342
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Adds host (97 B/pixel) and GPU (72 B/pixel) memory guards on the numpy and cupy dispatch branches of watershed_mfd. The MFD float64 fractions buffer (8 channels x 8 bytes = 64 B/pixel) is the dominant cost vs. the 8 B/pixel D8 flow direction array. Dask paths are unchanged -- per-tile allocations are bounded by the user's chunk size.
This was referenced Apr 29, 2026
brendancol
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Apr 29, 2026
…1348) Mirrors the pattern from watershed_d8 (#1330) and watershed_mfd (#1342). CPU peak is 33 B/pixel (single-channel float64 angle, same as D8). GPU peak is 24 B/pixel (caller's flow_dir + pour_points + result). Guards run on numpy/cupy dispatch paths; dask paths skip them since per-tile allocations are bounded by chunk size.
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Summary
_check_memoryand_check_gpu_memoryguards (50% threshold) to the numpy and cupy dispatch branches ofwatershed_mfdCloses #1339.
Test plan
pytest xrspatial/hydro/tests/test_watershed_mfd.py(17 passed: 12 existing + 5 new)pytest xrspatial/hydro/tests/(635 passed; one unrelatedtest_basin_d8::test_basin_dask_temp_cleanupflake from parallel agents sharing/tmp/xrs_bdry_*, passes in isolation)