Minimum CMake version

Problem

Just curious why the CMake minimum version is set to 3.20? It builds fine with version 3.18, and that seems to be the version you need to use when building on the SDSC Expanse system (which I believe others use the solver on too). If there is a different set of modules, etc. that someone can point me to which works on Expanse with CMake >= 3.20, that would help!

Also, if a user does need to change the minimum version to build on a particular system, this needs to be changed in 8 different places:

>>> grep -ri 'cmake_minimum_required' .
./Code/CMakeLists.txt:cmake_minimum_required(VERSION 3.20)
./Code/ThirdParty/parmetis_internal/simvascular_parmetis_internal/CMakeLists.txt:cmake_minimum_required(VERSION 3.20)
./Code/ThirdParty/gklib_internal/simvascular_gklib_internal/CMakeLists.txt:cmake_minimum_required(VERSION 3.20)
./Code/ThirdParty/metis_internal/simvascular_metis_internal/CMakeLists.txt:cmake_minimum_required(VERSION 3.20)
./Code/ThirdParty/tinyxml/simvascular_tinyxml/CMakeLists.txt:cmake_minimum_required(VERSION 3.20)
./Code/ThirdParty/tetgen/simvascular_tetgen/CMakeLists.txt:cmake_minimum_required(VERSION 3.20)
./Externals/CMakeLists.txt:cmake_minimum_required(VERSION 3.20)
./CMakeLists.txt:cmake_minimum_required(VERSION 3.20)

Solution

I know it's a good idea to set the minimum to make sure everything is up to date, but maybe it makes sense to set the minimum version only once so building on systems that need to change this can be done with just one change?

Additional context

No response

Code of Conduct

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Start by inspecting the eight CMakeLists.txt files named in the issue and comparing their cmake_minimum_required declarations. Check how the top-level, Code, Externals, and bundled ThirdParty builds are connected, then test the resulting configuration with CMake 3.18 and 3.20. Done means the minimum version can be changed in one place without breaking the listed build areas.