Feature face connectivity test

[Davknapp]

Used to analyse the bug in #778

Idea: For every class construct a cmesh of two trees. Tree B created by shifting Tree A along the normal of a given face. Then Tree A and B share a common face.

The function to construct the cmesh gives the possibility to to connect the trees via every face and for every possible orientation.

To check the correctness of the face-neighbor along a tree boundary:

1. Construct all children at the tree boundary.
2. Compute the face 'cf' of each child at the boundary.
3. Extrude the face on the neighbouring tree.
4. Check if the face touching the tree boundary has the same coordinates as the face 'cf'

Currently done: Construction of a cmesh with shifted tree along faces

• [x] Bugs in Tet-version
• [x] pyra-version for face 1
• [x] pyra-version for face 4
• [x] triangle_normal for face 1
• [ ] Prisms not implemented
• [x] No orientation implemented
• [ ] Test itself not implemented

Pleas mark the above boxes as done if implemented.

Hopefully this will find the bug in #778 and a follow-up PR might solve it.

All these boxes must be checked by the reviewers before merging the pull request:

As a reviewer please read through all the code lines and make sure that the code is fully understood, bug free, well-documented and well-structured.

General

• [ ] The reviewer executed the new code features at least once and checked the results manually

• [ ] The code follows the t8code coding guidelines

• [ ] New source/header files are properly added to the Makefiles

• [ ] The code is well documented

• [ ] All function declarations, structs/classes and their members have a proper doxygen documentation

• [ ] All new algorithms and data structures are sufficiently optimal in terms of memory and runtime (If this should be merged, but there is still potential for optimization, create a new issue)

Tests

• [ ] The code is covered in an existing or new test case using Google Test

Github action

• [ ] The code compiles without warning in debugging and release mode, with and without MPI (this should be executed automatically in a github action)

• [ ] All tests pass (in various configurations, this should be executed automatically in a github action)

  If the Pull request introduces code that is not covered by the github action (for example coupling with a new library):

  • [ ] Should this use case be added to the github action?
  • [ ] If not, does the specific use case compile and all tests pass (check manually)

Scripts and Wiki

• [ ] If a new directory with source-files is added, it must be covered by the script/find_all_source_files.scp to check the indentation of these files.
• [ ] If this PR introduces a new feature, it must be covered in an example/tutorial and a Wiki article.

Licence

• [ ] The author added a BSD statement to doc/ (or already has one)

[lukasdreyer]

#797 was merged without a test. What is this test missing to be merged?