Remove tropter test cases and make sure all tests pass with casadi

[aymanhab]

Fixes issue #<issue_number>

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• updated.

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[nickbianco]

Hey @aymanhab, I just noticed you started working on this. I think I misunderstood your message from last week; I was under the impression that you were going to disable the test suite for tropter when building the conda packages, and not remove them directly here. I was hoping to address all the tropter changes at once (i.e., remove the tropter libraries and the tests together). I'm a bit hesitant to gut out the tests while the tropter solver still exists as an option.

Is there a way to build the conda packages without tropter for now (i.e., by setting the OPENSIM_WITH_TROPTER flag)?

[aymanhab]

No problem @nickbianco I actually have a conda package without tropter using the cmake option already (https://anaconda.org/opensim_admin/opensim/files)
I removed the tests from the tree on a branch to make sure there're no side effects on MocoTests since that's the most entangled piece, and I started removing the actual cmake flags. I agree they should all go together (tests and code removal). You can take the branch over if you want.

[aymanhab]

@nickbianco I went ahead and removed references to tropter from the build system and ci, and the last remaining piece is that some python tests in test_moco.py are failing because they were using tropter without checking if available

opensim-core/Bindings/Python/tests/test_moco.py

Line 443 in 3783fbe

self.assertAlmostEqual(sol.getParameter("sphere_mass") + sol.getParameter("sphere2_mass"),

When you have a chance let me know if I should remove some/all of these tests that use tropter or convert to casadi

Thank you

[nickbianco]

@aymanhab it would be best to keep those tests and convert them all to use MocoCasADiSolver. All usages of initTropterSolver can be replaced with initCasADiSolver.

Were you planning on removing the tropter libraries as part of this PR too?

[aymanhab]

@nickbianco My plan was to make the build/install/test all work first and removed from the make system on this branch and then remove the folders (in case something comes up that force a backtrack) but it can go in any order. Do you expect any results to change when swapping the solvers?

[nickbianco]

That sounds like a good plan. Theoretically, the tests should pass with either solver, but it's possible that differences in each implementation could lead to different numerical results. I'm happy to debug any such cases that arise.

We will also need to eventually remove Tropter from all of the tests under the Moco test folder.

[aymanhab]

@nickbianco I'll pass this on to you to do the internal cleanup of the Moco tests. The python test cases pass on linux but not on windows or osx though the failures are for reasons unrelated to this PR as far as I can tell. Just let me know if you want me to investigate these failures. Thank you.

[nickbianco]

Sure @aymanhab. I'll pick this up starting next week.

[aymanhab]

Thanks @nickbianco 👍
Something to keep in mind when looking into test failures, the moco python tests with casadi all succeed when run from dev/build environment directly but fail when run from install environments on windows/mac