1038 odeintegrator can run indefinitely

[reneSchm]

Changes and Information

Please briefly list the changes (main added features, changed items, or corrected bugs) made:

• Fix a bug where OdeIntegrator would run indefinitely.
• Allow integrators to force a given step size.

If need be, add additional information and what the reviewer should look out for in particular:

• Please look through the newly added tests. They impose assumptions on the IntegratorCore::step method we may want to discuss.
  • e.g., a forced step currently always counts as successful
  • is there maybe something missing?
• Please proofread the documentation, especially for IntegratorCore::step
• Should we document the unused argument force_step_size of EulerIntegratorCore::step? How?

Merge Request - Guideline Checklist

Please check our git workflow. Use the draft feature if the Pull Request is not yet ready to review.

Checks by code author

• [x] Every addressed issue is linked (use the "Closes #ISSUE" keyword below)
• [x] New code adheres to coding guidelines
• [x] No large data files have been added (files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• [x] Tests are added for new functionality and a local test run was successful (with and without OpenMP)
• [x] Appropriate documentation for new functionality has been added (Doxygen in the code and Markdown files if necessary)
• [x] Proper attention to licenses, especially no new third-party software with conflicting license has been added
• [x] (For ABM development) Checked benchmark results and ran and posted a local test above from before and after development to ensure performance is monitored.

Checks by code reviewer(s)

• [ ] Corresponding issue(s) is/are linked and addressed
• [ ] Code is clean of development artifacts (no deactivated or commented code lines, no debugging printouts, etc.)
• [ ] Appropriate unit tests have been added, CI passes, code coverage and performance is acceptable (did not decrease)
• [ ] No large data files added in the whole history of commits(files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• [ ] On merge, add 2-5 lines with the changes (main added features, changed items, or corrected bugs) to the merge-commit-message. This can be taken from the briefly-list-the-changes above (best case) or the separate commit messages (worst case).

Closes #1038

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.24%. Comparing base (2994f76) to head (0716e48).

:exclamation: Current head 0716e48 differs from pull request most recent head 59f4f1a

Please upload reports for the commit 59f4f1a to get more accurate results.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1046 +/- ## ========================================== + Coverage 96.23% 96.24% +0.01% ========================================== Files 128 128 Lines 10852 10861 +9 ========================================== + Hits 10443 10453 +10 + Misses 409 408 -1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[lenaploetzke]

With these changes, the application where the problem occurred works as expected. Will review the code soon.

[reneSchm]

Nevertheless, I still get the warning "Adaptive step sizing failed. Forced at least one integration step of size dt_min." if the last step is forced.

The message should only appear if a non-forced step failed to adapt, i.e. the stepper wanted to make a step smaller than dt_min. Are you sure this message is due to the last step?

[reneSchm]

@HenrZu @lenaploetzke I think I don't like the force_step_size approach anymore, it makes both the OdeIntegrator as well as the IntegratorCore weirdly complicated. I made another version in #1049, could you please check that one out instead?

[reneSchm]

Closed in favor of v2.