Vectorize MALI mesh flood-fill extrapolation for large-mesh speedup - #753
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trhille wants to merge 1 commit into
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Vectorize MALI mesh flood-fill extrapolation for large-mesh speedup#753trhille wants to merge 1 commit into
trhille wants to merge 1 commit into
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The per-cell Python neighbor loop used to extrapolate beta/muFriction/ stiffnessFactor into undefined regions is O(rings x remaining-empty-cells) and slow on large meshes. Replace it with a shared extrapolate_into_mask() helper that processes only the active BFS frontier each ring using vectorized numpy neighbor reductions, preserving the same min/idw/value semantics. Also vectorize the one-time grounded-neighbor dilation in extrapolate_variable.py. On an 829k-cell GIS mesh (muFriction grounded-mask case) this is ~107x faster for min (68.2s -> 0.64s, bitwise identical) and ~61x for idw (81.2s -> 1.32s, identical to 4e-15 sum-order roundoff). The new code also terminates cleanly on voids disconnected from any valid data, which the original loop could not.
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The per-cell Python neighbor loop used to extrapolate beta/muFriction/ stiffnessFactor into undefined regions is O(rings x remaining-empty-cells) and slow on large meshes. Replace it with a shared extrapolate_into_mask() helper that processes only the active BFS frontier each ring using vectorized numpy neighbor reductions, preserving the same min/idw/value semantics. Also vectorize the one-time grounded-neighbor dilation in extrapolate_variable.py.
On an 829k-cell GIS mesh (muFriction grounded-mask case) this is ~107x faster for min (68.2s -> 0.64s, bitwise identical) and ~61x for idw (81.2s -> 1.32s, identical to 4e-15 sum-order roundoff). The new code also terminates cleanly on voids disconnected from any valid data, which the original loop could not.