feat: non-linear fluxes #183

Job	Run time
cppcheck	4m 58s
pre-commit	18s
macos-mamba	15m 19s
linux-mamba (gcc-9, gcc, gcc-9 g++-9, gcc-9, g++-9)	16m 38s
linux-mamba (gcc-10, gcc, gcc-10 g++-10, gcc-10, g++-10)	16m 54s
linux-mamba (gcc-11, gcc, gcc-11 g++-11, gcc-11, g++-11)	17m 30s
linux-mamba (gcc-12, gcc, gcc-12 g++-12, gcc-12, g++-12)	17m 33s
linux-mamba (clang-11, clang, clang-11, clang-11, clang++-11)	18m 43s
linux-mamba (clang-12, clang, clang-12, clang-12, clang++-12)	17m 43s
linux-mamba (clang-13, clang, clang-13, clang-13, clang++-13)	16m 53s
linux-mamba (clang-14, clang, clang-14, clang-14, clang++-14)	16m 56s
	2h 39m 25s

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