Fix spatial loss map step labeling

[vikramsingh920]

Describe your changes

Fixes an issue where out-of-range values in val_steps_to_log could cause
spatial loss maps to be associated with the wrong forecast steps.

< Summary of the changes.>

Updated test_step to keep track of the filtered evaluation steps and use them
when generating spatial loss map titles and PDF filenames. Added a regression
test to verify that out-of-range steps are skipped and valid steps are labeled
correctly.

< Please also include relevant motivation and context. >

When val_steps_to_log contains steps outside the test rollout length, those
steps are filtered out when calculating the spatial loss. However, the original
val_steps_to_log was still used when labeling and saving the loss maps. This
could cause the loss maps to be associated with the wrong forecast steps and
PDF filenames.

< List any dependencies that are required for this change. >
No new dependencies are required.

Issue Link

fixes #747
< Link to the relevant issue or task, if applicable > (e.g. closes #00 or solves #00)

Type of change

• [✅] 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📖 Documentation (Addition or improvements to documentation)

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[GiGiKoneti]

Thanks @vikramsingh920. The core synchronization via _test_spatial_steps and the regression test look good, but a few items need fixing:

1. Revert unrelated files: Please revert neural_lam/config.py and neural_lam/train_model.py (add_safe_globals is out of scope for [Bug] Spatial loss map titles and saved PDFs mislabeled in on_test_epoch_end when val_steps_to_log contains out-of-range steps #747).
2. Fix ty type checking error in neural_lam/models/module.py (lines 890–893): Line 891 self.logger.save_dir fails ty because the ignore comment was placed on line 892 (exist_ok=True,). If directory creation was only needed for the test fixture, create the directory in the test instead of modifying create_metric_log_dict.
3. Guard lower bound in test_step: Use 1 <= step <= spatial_loss.shape[1] instead of step <= spatial_loss.shape[1] to prevent non-positive steps (0, -1) from silently slicing from the end via negative indexing in programmatic setups.
4. Rebase after Reject step < 1 in --*_steps_to_log and --var_leads_metrics_watch #746: Per @sadamov's note in [Bug] Spatial loss map titles and saved PDFs mislabeled in on_test_epoch_end when val_steps_to_log contains out-of-range steps #747, please rebase on main once Reject step < 1 in --*_steps_to_log and --var_leads_metrics_watch #746 lands.
5. Clean up diff: Please revert the tuple unpacking change in tests/test_plotting.py:558.

cc : @sadamov

[vikramsingh920]

Thanks for the review @GiGiKoneti. I have addressed the points in the latest push:

1. Reverted neural_lam/config.py and neural_lam/train_model.py.
2. Fixed the ty error by creating the directory inside the test fixture rather than create_metric_log_dict.
3. Added the 1 <= step <= spatial_loss.shape[1] lower-bound guard in test_step and expanded regression test coverage to include non-positive steps (-1, 0).
4. Reverted the tuple unpacking syntax in tests/test_plotting.py:558.
5. Will rebase on main once Reject step < 1 in --*_steps_to_log and --var_leads_metrics_watch #746 lands.

[GiGiKoneti]

two small issues remain:

1. black and flake8 failures: pre-commit run flake8 fails on lines exceeding 80 chars in neural_lam/models/module.py:659 and tests/test_plotting.py:928, 955, and black reformats module.py.
2. Tuple unpacking at tests/test_plotting.py:558: Line 558 still drops the parentheses around (init_states, ...); please revert to keep the diff clean.

[vikramsingh920]

Thanks @GiGiKoneti, I addressed both comments in the latest push:

1. Wrapped long lines in neural_lam/models/module.py and tests/test_plotting.py so flake8 and black pass cleanly.
2. Restored the tuple unpacking parentheses at tests/test_plotting.py:558 to keep the diff clean.

[vikramsingh920]

Hi @GiGiKoneti and @sadamov , when you get a chance, could you please take a look at my PR #752 and let me know if there’s anything I should change or improve? I’d really appreciate your feedback. Thanks!

[GiGiKoneti]

Since #746 is still open, this PR will need a rebase on main once #746 lands before it can be merged. Leaving final review and sequencing to Simon.

[vikramsingh920]

hii @GiGiKoneti and @sadamov , #746 has now been merged, so I’ve rebased #752 onto the latest main and addressed the previous review comments.
Could you please take a look at #752 when you get a chance? Thanks!