Add numerical support of other real types (Float32)

[huiyuxie]

Address parts of #591 and redo #1604.

Tasks:

• acoustic_perturbation_2d
• compressible_euler_1d, compressible_euler_2d, compressible_euler_3d
• unit tests for above

[github-actions]

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Created with ❤️ by the Trixi.jl community.

[ranocha]

Thanks a lot for your contribution. Please find below some comments/suggestions.

[huiyuxie]

General question here: Is it better to conduct unit testing while making changes, or to perform the tests after completing all the changes? Are there any good examples of testing from this repository? Thanks!

[ranocha]

General question here: Is it better to conduct unit testing while making changes, or to perform the tests after completing all the changes? Are there any good examples of testing from this repository? Thanks!

When you're working on numerical fluxes, you can add some unit tests, e.g., to parts like

Trixi.jl/test/test_unit.jl

Lines 633 to 660 in 1745df4

	@timed_testset "Consistency check for HLL flux (naive): CEE" begin
	flux_hll = FluxHLL(min_max_speed_naive)
	# Set up equations and dummy conservative variables state
	equations = CompressibleEulerEquations1D(1.4)
	u = SVector(1.1, 2.34, 5.5)
	orientations = [1]
	for orientation in orientations
	@test flux_hll(u, u, orientation, equations) ≈ flux(u, orientation, equations)
	end
	equations = CompressibleEulerEquations2D(1.4)
	u = SVector(1.1, -0.5, 2.34, 5.5)
	orientations = [1, 2]
	for orientation in orientations
	@test flux_hll(u, u, orientation, equations) ≈ flux(u, orientation, equations)
	end
	equations = CompressibleEulerEquations3D(1.4)
	u = SVector(1.1, -0.5, 2.34, 2.4, 5.5)
	orientations = [1, 2, 3]
	for orientation in orientations
	@test flux_hll(u, u, orientation, equations) ≈ flux(u, orientation, equations)
	end
	end

for the compressible Euler equations. Here, you could add additional tests using inputs with eltype(u) == Float32.

We should also add some full integration tests once something works completely - maybe by adding one or two new example elixirs showing how to run simulations with Float32.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.12%. Comparing base (3b52a30) to head (60836bb).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1909      +/-   ##
==========================================
+ Coverage   96.11%   96.12%   +0.01%     
==========================================
  Files         460      460              
  Lines       36926    36952      +26     
==========================================
+ Hits        35490    35520      +30     
+ Misses       1436     1432       -4     

Flag	Coverage Δ
unittests	96.12% <100.00%> (+0.01%)	⬆️

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[huiyuxie]

Hi @ranocha I have revised the code based on our discussion. Please review it once more, and if this version is satisfactory, I will apply similar revisions to the subsequent tasks.

For dual numbers, I have no idea whether it will be copied to the GPU and I think CUDA.jl does not directly support this type. If they are to be executed on GPUs, I will explore alternative methods (probably through struct) to manage them.

For documentation, are you referring to a general overview that explains the purpose of using a function like oftype, or to detailed documentation that points to each specific instance in the code?

[ranocha]

Thanks a lot! I just have some minor suggestions.

For documentation, are you referring to a general overview that explains the purpose of using a function like oftype, or to detailed documentation that points to each specific instance in the code?

I had something in mind like adding a new section to https://trixi-framework.github.io/Trixi.jl/stable/conventions/ where we explain

• why we use 0.5f0 * instead of 0.5 *
• why we use patterns such as RealT = eltype(x) and v1_prime = zero(RealT) or A = convert(RealT, 0.2)

There is no need to point to specific code lines from my point of view.

[ranocha]

@sloede Could you please have a look as well?

[ranocha]

Thanks! Let's please wait for a review by @sloede before you start modifying more files.

[huiyuxie]

I left a message in slack - Please check and collaborate as otherwise there will be more and more bugs in the long run.

[ranocha]

Thanks a lot! The checkbox "unit tests for above" in the first ost is still open. Do you want to add more unit tests to this PR?

If not, I think it would be nice to go ahead and merge this PR soon so that others can use the infrastructure for adding new unit tests (and using the existing tests) in other PRs

[ranocha]

Could you please run the formatter, e.g., like this?

import Pkg
Pkg.activate(temp = true)
Pkg.add(PackageSpec(name = "JuliaFormatter", version="1.0.45"))
using JuliaFormatter
format(["benchmark", "examples", "ext", "src", "test", "utils"])

(when executed in the main directory of your clone of Trixi.jl)

[huiyuxie]

Please review again - already formatted and added 3D test

Sorry that I am extremely busy until next Wednesday (including the weekends) please wait and take your time :)

[huiyuxie]

Please help me rerun CI as I have no rights to do so

[sloede]

Looks nearly ready to merge from my side, just a few small questions 🙂

[ranocha]

Thanks a lot!