I’ve just upgraded to Fedora 31 and I am trying to recompile ROOT. Python 3 became the default on Fedora 31, however, I would like to compile ROOT with python 2.7. I did
– Constructing LLVMBuild project information
CMake Error at interpreter/llvm/src/CMakeLists.txt:665 (message):
Unexpected failure executing llvm-build:
– Configuring incomplete, errors occurred!
If I don’t do any python modification and cmake uses default python 3, it goes through. It seems in case I specify python2, it can’t find numpy and has problems with tmva. However, disabling tmva does not change the result.
Problem solved. -D PYTHON_EXECUTABLE requires absolute path. It would be helpful if no path was causing an error or there was information about this requirement in the documentation.
I don’t know whether you are aware of it, but ROOT 6.18.04 is available through the package manager on Fedora, as well as bindings for Python 2 and 3 – which can be installed in parallel. A simple sudo dnf install root python2-root will save you the hassle of compiling and updating everything yourself.
Edit: I just remembered that I installed that in Fedora 30 and haven’t checked yet after the upgrade.
I had another look yesterday and the python2-root package was removed in Fedora 31. So even if you did trust the package manager, you would have had to compile it yourself.