added error warning to KdV

[cwittens]

not sure if I should also have a test for this third error case but I just realised if D3 == nothing KdV will make strange stuff

[github-actions]

Benchmark Results (Julia v1.10)

Time benchmarks

	main	189696e...	main / 189696e...
bbm_1d/bbm_1d_basic.jl - rhs!:	13.9 ± 0.29 μs	14.1 ± 0.47 μs	0.987 ± 0.039
bbm_1d/bbm_1d_fourier.jl - rhs!:	0.53 ± 0.0099 ms	0.527 ± 0.31 ms	1 ± 0.59
bbm_bbm_1d/bbm_bbm_1d_basic_reflecting.jl - rhs!:	0.0814 ± 0.0011 ms	0.0809 ± 0.00044 ms	1.01 ± 0.015
bbm_bbm_1d/bbm_bbm_1d_dg.jl - rhs!:	0.0343 ± 0.0005 ms	0.034 ± 0.00044 ms	1.01 ± 0.02
bbm_bbm_1d/bbm_bbm_1d_relaxation.jl - rhs!:	28.4 ± 0.86 μs	27.2 ± 0.39 μs	1.04 ± 0.035
bbm_bbm_1d/bbm_bbm_1d_upwind_relaxation.jl - rhs!:	0.0486 ± 0.00054 ms	0.0484 ± 0.00057 ms	1 ± 0.016
hyperbolic_serre_green_naghdi_1d/hyperbolic_serre_green_naghdi_dingemans.jl - rhs!:	4.29 ± 0.03 μs	4.37 ± 0.049 μs	0.981 ± 0.013
kdv_1d/kdv_1d_basic.jl - rhs!:	1.46 ± 0.02 μs	1.4 ± 0.011 μs	1.04 ± 0.016
kdv_1d/kdv_1d_implicit.jl - rhs!:	1.47 ± 0.02 μs	1.41 ± 0.011 μs	1.04 ± 0.016
serre_green_naghdi_1d/serre_green_naghdi_well_balanced.jl - rhs!:	0.197 ± 0.0084 ms	0.199 ± 0.008 ms	0.991 ± 0.058
svaerd_kalisch_1d/svaerd_kalisch_1d_dingemans_relaxation.jl - rhs!:	0.145 ± 0.0039 ms	0.147 ± 0.0039 ms	0.987 ± 0.037
time_to_load	1.91 ± 0.01 s	1.9 ± 0.0079 s	1 ± 0.0067

Memory benchmarks

	main	189696e...	main / 189696e...
bbm_1d/bbm_1d_basic.jl - rhs!:	1 allocs: 4.12 kB	1 allocs: 4.12 kB	1
bbm_1d/bbm_1d_fourier.jl - rhs!:	1 allocs: 4.12 kB	1 allocs: 4.12 kB	1
bbm_bbm_1d/bbm_bbm_1d_basic_reflecting.jl - rhs!:	5 allocs: 1.17 kB	5 allocs: 1.17 kB	1
bbm_bbm_1d/bbm_bbm_1d_dg.jl - rhs!:	10 allocs: 8.62 kB	10 allocs: 8.62 kB	1
bbm_bbm_1d/bbm_bbm_1d_relaxation.jl - rhs!:	2 allocs: 8.25 kB	2 allocs: 8.25 kB	1
bbm_bbm_1d/bbm_bbm_1d_upwind_relaxation.jl - rhs!:	2 allocs: 8.25 kB	2 allocs: 8.25 kB	1
hyperbolic_serre_green_naghdi_1d/hyperbolic_serre_green_naghdi_dingemans.jl - rhs!:	0 allocs: 0 B	0 allocs: 0 B
kdv_1d/kdv_1d_basic.jl - rhs!:	0 allocs: 0 B	0 allocs: 0 B
kdv_1d/kdv_1d_implicit.jl - rhs!:	0 allocs: 0 B	0 allocs: 0 B
serre_green_naghdi_1d/serre_green_naghdi_well_balanced.jl - rhs!:	0.075 k allocs: 0.66 MB	0.075 k allocs: 0.66 MB	1
svaerd_kalisch_1d/svaerd_kalisch_1d_dingemans_relaxation.jl - rhs!:	0.042 k allocs: 0.315 MB	0.042 k allocs: 0.315 MB	1
time_to_load	0.153 k allocs: 14.5 kB	0.153 k allocs: 14.5 kB	1

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[coveralls]

Pull Request Test Coverage Report for Build 17209599772

Details

• 14 of 14 (100.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 98.333%

---

Totals
Change from base Build 17155945350:	0.01%
Covered Lines:	2300
Relevant Lines:	2339

---

💛 - Coveralls

[JoshuaLampert]

That's a good idea. What about the other equations? What happens if we do not pass a second-order operator? Maybe it makes sense to check this in general and also already during the creation of the Semidiscretization. We could add a check_solver(equations, solver) (or similar) function called within Semidiscretization that dispatches on equations and throws an error if an operator is not defined, which is needed.

[cwittens]

Yes thats a good idea!

[JoshuaLampert]

What is the status of this PR?

[cwittens]

I currently dont have the time to do

That's a good idea. What about the other equations? What happens if we do not pass a second-order operator? Maybe it makes sense to check this in general and also already during the creation of the Semidiscretization. We could add a check_solver(equations, solver) (or similar) function called within Semidiscretization that dispatches on equations and throws an error if an operator is not defined, which is needed.

Should I close this PR and open an issue so that it is not forgotten?

[JoshuaLampert]

Ok, no worries. I would also be fine with keeping this PR open. I think then we also won't forget about it :)

[JoshuaLampert]

I introduced a new function check_solver defined for each equations, which need D2 or D3. Does this look good to you, @cwittens?

[cwittens]

LGTM.
Does this need a News.md entry or not because it is internal only?

[JoshuaLampert]

Does this need a News.md entry or not because it is internal only?

I would say it's fine without because it's internal.

[ranocha]

I guess this can be merged, @JoshuaLampert?