Guard owa() against unbounded criteria stack (#1370)#1375
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owa() concatenates every weighted criterion layer into a single float64 stack via xr.concat, then sorts that stack descending along the criterion axis. Peak working memory scales as n_criteria * H * W * 8, with the sort roughly doubling that. A caller passing 100 criteria over a 10000x10000 raster needs ~80 GB just for the stack; the sort takes it to ~160 GB. Add a host-memory guard on the eager numpy path that refuses inputs whose stack would exceed 50% of available RAM. Dask-backed inputs skip the guard since per-chunk allocations are bounded. Tests: oversize raises MemoryError; normal-size succeeds; error message names the criterion count and grid shape.
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Summary
owa()that estimates the float64 criteria stack size (n_criteria * H * W * 8) and raisesMemoryErrorwhen it would exceed 50% of available RAM.TestOWAMemoryGuard: oversize raises, normal succeeds, error message names the criterion count and grid shape.Closes #1370.
Test plan
pytest xrspatial/tests/test_mcda.pypasses (169 tests, including the 3 new ones).owa()on a small Dataset returns the expected composite surface.