Transition to GLM

[nicholasbl]

This hefty PR strips out the custom linear algebra library and replaces it with GLM, a fairly popular and high performance library. This is the first step toward using quaternions instead of a vector and rotation for user-facing simulation_data classes, as discussed with @qualand (Bill).

Aside from allowing some more traditional syntax, GLM improves the performance by around 10% on my machines, and opens the door to using AVX instructions explicitly for additional gains. However: debug builds perform slower, in some cases twice as slow due to the indirection GLM needs to provide platform specific optimizations.

This is a draft as the Optix test is crashing, but I'm not yet sure if it's my fault or not.

Changes:

• Add in the cmake package manager CPM to make pulling in 3rd party libraries easier (wrapping FetchContent)
• Move json library to CPM, and add in GLM
• Replace all uses of Vector3d and Matrix3d with glm::dvec3 and glm::dmat3, and optimize usage

Notes:

• Note that GLM vectors do have a [] operator, but it is more efficient to use .x, .y, .z accessors
• GLM allows more idiomatic expressions
  • add_vector has been removed. These expressions can be made using normal syntax: variable = a * v + b * y
  • matrix * matrix and matrix * vector expressions can now be made using normal syntax
• More optimizations can be made to make better use of SIMD
• A small change was made to the Rectangle aperture to make is_in faster; this could be done for all apertures

[nicholasbl]

@jmaack24 Bill suggested I ping you on this PR. This is a pretty large PR, so please let me know if I've messed something up.

[nicholasbl]

A few tests failing here that didn't fail on my hardware. Looks like the debug ones are duration; that's expected due to the slow performance of GLM in debug mode. The release ones are failing from uninitialization, which I thought I had fixed, but I'll get that fixed up soon enough.

[coveralls]

Pull Request Test Coverage Report for Build 21916285546

Details

• 913 of 970 (94.12%) changed or added relevant lines in 35 files are covered.
• 71 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-1.2%) to 86.885%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
coretrace/simulation_data/sun.hpp	4	5	80.0%
coretrace/simulation_runner/embree_runner/trace_embree.cpp	29	30	96.67%
coretrace/simulation_data/json_helpers.hpp	2	4	50.0%
coretrace/simulation_data/aperture.cpp	23	27	85.19%
coretrace/simulation_data/vector_utility.hpp	0	4	0.0%
coretrace/simulation_runner/native_runner/generate_ray.cpp	13	17	76.47%
coretrace/simulation_data/element.hpp	6	11	54.55%
coretrace/simulation_data/matvec.cpp	36	42	85.71%
coretrace/simulation_runner/embree_runner/embree_helper.cpp	14	21	66.67%
coretrace/simulation_runner/native_runner/tracing_errors.cpp	41	52	78.85%

Files with Coverage Reduction	New Missed Lines	%
coretrace/simulation_data/surface.cpp	1	94.04%
coretrace/simulation_data/matvec.cpp	70	32.14%

Totals
Change from base Build 21458642404:	-1.2%
Covered Lines:	6406
Relevant Lines:	7373

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💛 - Coveralls

[nicholasbl]

Struggling to get coverage to succeed. Getting weird negative counts.

[jmaack24]

Struggling to get coverage to succeed. Getting weird negative counts.

Bill and I both ran into this. Something to do with the multi-threading (even though that's not supposed to be a problem). After trying to fix it, we eventually just turned off the multi-threaded tests in coverage.

Ignoring them is a good way to go for now. Maybe we can try to fix this after the beta release.

[nicholasbl]

Looks like it worked this time. I think this is ready for review; I don't have permissions to add reviewers, however.

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Pull request overview

Copilot reviewed 106 out of 107 changed files in this pull request and generated 4 comments.

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[jmaack24]

Looks good. No issues.

[nicholasbl]

Excellent. Looks like we are all good to go.