[Jammy2211]

Refs PyAutoLabs/PyAutoFit#1565 (census option O3 of the ci-timing-fast-tests epic; the PyAutoFit half, O2, is PyAutoFit feature/defer-import-scipy-special). Independent of that PR.

Summary

autolens/__init__.py:143 imports potential_correction, whose __init__ imports visualize, which imported matplotlib.pyplot (and cm, ticker, MaxNLocator, make_axes_locatable, matplotlib) at module level: ~0.32 s on every import autolens for six drawing functions almost no process calls. The imports now live inside the five functions that draw, matching what potential_correction/mesh.py:178 and iterative.py:661 already do. Nothing outside the module referenced visualize.plt et al.; scipy.interpolate / scipy.spatial stay at module level (autoarray already imports scipy.spatial).

Measured

	before	after
-X importtime matplotlib.pyplot under import autolens	325 ms cumulative	absent
import autolens wall (best of 3, fresh processes)	1.54 s	1.17 s (this PR alone); 1.09 s with the PyAutoFit PR too

Still imported at top level and deliberately left alone: matplotlib core via autoarray.plot.* (a real plotting layer, other repo) and scipy.special via autogalaxy.profiles.mass.abstract.mge (a real numerical dependency, other repo).

API Changes

None. Same functions, same names, same figures.

Validation

• python3 -m pytest -q -n auto: 623 passed, 1 xfailed.
• Three new tests in test_autolens/potential_correction/test_visualize_import.py: pyplot absent from sys.modules after import autolens in a fresh process; no matplotlib name bound on the module (so a name put back at the top would fail a test rather than silently re-import pyplot); the drawing functions still exported.
• An AST pass confirms every plt/mpl/cm/ticker/MaxNLocator/make_axes_locatable load resolves to a local import. Four of the five drawing functions were exercised under Agg; show_fit_dpsi / show_fit_dpsi_src need a constructed fit and are covered by the import tests only — their deferred import is the same single plt line.

Guard

Import deferral only — no plotting logic, likelihood or JAX change.

pending-release: lands in the next PyAutoLens release; timings/unit/PyAutoLens.jsonl's import_s reads it back after merge.

🤖 Generated with Claude Code

https://claude.ai/code/session_01WYcmRnZf3cbC5Wth9bCkEg

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