perf(galaxy): skip the second deflection call for the over-sampled grid at sub-size 1 (PyAutoArray#514) - #595
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…id at sub-size 1 (PyAutoArray#514) `Galaxy.traced_grid_2d_from` called `deflections_yx_2d_from` twice — once for the slim grid and once for `grid.over_sampled`. When the grid's over-sampler is uniform at sub-size 1 — the pixelization grid in every CPU likelihood cell — `grid.over_sampled` is the slim grid in the same order, so the second call recomputes a bit-identical answer at full cost and is now reused instead. The sub-size is host numpy, so the guard is a static Python bool and the branch is resolved at JAX trace time rather than becoming a traced `cond`. The equivalent guard in `Tracer.traced_grid_2d_list_from` (PyAutoLens) measures the tracer/raw deflection ratio on hst dropping from 2.52x to 1.41x for Isothermal and 1.94x to 0.88x for PowerLaw, with every pinned value still PASSING — the change is bit-identical. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HWjPT94MPbEHT45kJmDpDh
This was referenced Sep 2, 2026
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Summary
Phase 1 of the
numpy-deflections-cpuepic (PyAutoArray#514).Galaxy.traced_grid_2d_fromcalleddeflections_yx_2d_fromtwice on aGrid2D: once for the grid and once forgrid.over_sampled. At a uniform over-sample size of 1 the over-sampled grid is the slim grid in the same order, so the second call doubled the deflection cost for a bit-identical result. Same guard as the companion PyAutoLens tracer change: the over-sample size is host numpy, so the branch is static at JAX trace time; sub-size > 1 is unchanged.API Changes
None — internal changes only.
See full details below.
Test Plan
test_autogalaxy: 1158 passed (new tests intest_autogalaxy/galaxy/test_galaxy.py: traced.over_sampledequals the separately traced over-sampled grid and differs from the untraced one, at sub-size 1 and 4; at sub-size 1 it equals the traced slim grid exactly).autolens_profilinglens cells hst: deflection pins PASSED (rtol 1e-6).Full API Changes (for automation & release notes)
Changed Behaviour
autogalaxy.galaxy.galaxy.Galaxy.traced_grid_2d_from— when every entry ofgrid.over_sample_sizeis 1, the over-sampled traced grid is aGrid2DIrregularcopy of the traced slim grid instead of a seconddeflections_yx_2d_fromcall (bit-identical values).Generated by the PyAutoLabs agent workflow. Companion PRs: PyAutoArray (
to_grid/Grid2D.over_sampled), PyAutoLens (Tracer.traced_grid_2d_list_from), autolens_profiling (scripts/lens/measurement package).Companion: PyAutoLabs/PyAutoArray#516