Fix/diffusive concentrations #311

Job	Run time
CMake Matrix Test. (Linux Min GCC, ubuntu-20.04, gcc-9, g++-9, 3.8, 3.19.x, ON, OFF, static)	9m 19s
CMake Matrix Test. (Linux Min GCC, ubuntu-20.04, gcc-9, g++-9, 3.8, 3.19.x, ON, OFF, shared)	7m 25s
CMake Matrix Test. (Linux Min Clang, ubuntu-20.04, clang-9, clang++-9, 3.8, 3.19.x, ON, OFF, static)	4m 16s
CMake Matrix Test. (Linux Min Clang, ubuntu-20.04, clang-9, clang++-9, 3.8, 3.19.x, ON, OFF, shared)	3m 54s
CMake Matrix Test. (MacOS Min, macos-11, clang, clang++, 3.8, 3.19.x, ON, OFF, static)	34m 2s
CMake Matrix Test. (MacOS Min, macos-11, clang, clang++, 3.8, 3.19.x, ON, OFF, shared)	30m 20s
CMake Matrix Test. (Linux Max GCC, ubuntu-22.04, gcc-12, g++-12, 3.11, 3.22.x, ON, OFF, static)	9m 57s
CMake Matrix Test. (Linux Max GCC, ubuntu-22.04, gcc-12, g++-12, 3.11, 3.22.x, ON, OFF, shared)	7m 40s
CMake Matrix Test. (Linux SIMD, ubuntu-22.04, gcc-12, g++-12, 3.11, 3.22.x, OFF, ON, static)	10m 46s
CMake Matrix Test. (Linux SIMD, ubuntu-22.04, gcc-12, g++-12, 3.11, 3.22.x, OFF, ON, shared)	6m 44s
CMake Matrix Test. (Linux Max Clang, ubuntu-22.04, clang-14, clang++-14, 3.11, 3.22.x, ON, OFF, s...	9m 23s
CMake Matrix Test. (Linux Max Clang, ubuntu-22.04, clang-14, clang++-14, 3.11, 3.22.x, ON, OFF, s...	5m 45s
CMake Matrix Test. (MacOS Max, macos-13, clang, clang++, 3.11, 3.22.x, ON, OFF, static)	11m 8s
CMake Matrix Test. (MacOS Max, macos-13, clang, clang++, 3.11, 3.22.x, ON, OFF, shared)	9m 15s
	2h 39m 54s

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