Reset derived quantity objects data and t at the beginning of a simulation

[Allentro]

Proposed changes

I have implemented a fix to reset export.t and export.data at the beginning of a simulation, accompanied by a respective test. This PR resolves #728

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code refactoring
• Documentation Update (if none of the other choices apply)
• New tests

Checklist

• Black formatted
• Unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.40%. Comparing base (3d6b9da) to head (f08f0b5).

Additional details and impacted files

@@           Coverage Diff            @@
##           fenicsx     #733   +/-   ##
========================================
  Coverage    98.39%   98.40%           
========================================
  Files           27       27           
  Lines         1437     1439    +2     
========================================
+ Hits          1414     1416    +2     
  Misses          23       23           

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[RemDelaporteMathurin]

Initial round of comments, the fix obviously works fine, but it's not the right place for it.

[RemDelaporteMathurin]

Doing it here is not the right place.
This iterates through all the exports, which can be derived quantities, but also VTXExport or XDMFExport etc.

Instead, we could do it in write(), making use of the self._is_first_time_export attribute. For example here:

FESTIM/festim/exports/surface_quantity.py

Lines 75 to 76 in f08f0b5

	if self._first_time_export:
	header = ["t(s)", f"{title}"]

[RemDelaporteMathurin]

Alternatively we could do it here, but with an additional type check to only do this for derived quantities.

[RemDelaporteMathurin]

Can you parametrise this test to also check for other derived quantities (eg. TotalVolume)

[RemDelaporteMathurin]

Hey @Allentro what is the status of this?

[Allentro]

Hey @Allentro what is the status of this?

Hi Remi, sorry this has slipped my list. I'll get this complete tomorrow!

[RemDelaporteMathurin]

Hi @Allentro! Do you want someone else to pick up this PR?

[Allentro]

Hi @Allentro! Do you want someone else to pick up this PR?

Hi Remi,

This slipped my inbox.. I was just scrolling through my mentions and saw this. I'm happy to work on this tomorrow evening. Sorry for the delay on this.