I have tried building from source on a Mac M4 and initially got past the compiler issue as suggested in other topics and solved here (updated with paths to reflect homebrew installation on apple chips) with
export CC=/opt/homebrew/opt/llvm/bin/clang
export CXX=/opt/homebrew/opt/llvm/bin/clang++
export LDFLAGS="-L/opt/homebrew/opt/llvm/lib"
export CPPFLAGS="-I/opt/homebrew/opt/llvm/include"
So now I am able to run cmake .. with the following output
-- The C compiler identification is Clang 20.1.2
-- The CXX compiler identification is Clang 20.1.2
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /opt/homebrew/opt/llvm/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /opt/homebrew/opt/llvm/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found Git: /usr/bin/git (found version "2.39.5 (Apple Git-154)")
-- Using git describe for versioning
-- OpenMC version: 0.15.3
-- OpenMC dev state: true
-- OpenMC commit hash: 07f5334616c2ca92ad0a04dfa8c900e080509f70
-- OpenMC commit count: 5
-- OPENMC_USE_OPENMP ON
-- OPENMC_BUILD_TESTS ON
-- OPENMC_ENABLE_PROFILE OFF
-- OPENMC_ENABLE_COVERAGE OFF
-- OPENMC_USE_DAGMC OFF
-- OPENMC_USE_LIBMESH OFF
-- OPENMC_USE_MPI OFF
-- OPENMC_USE_MCPL OFF
-- OPENMC_USE_UWUW OFF
-- No build type selected, defaulting to RelWithDebInfo
-- Found OpenMP_C: -fopenmp=libomp (found version "5.1")
-- Found OpenMP_CXX: -fopenmp=libomp (found version "5.1")
-- Found OpenMP: TRUE (found version "5.1")
-- Found ZLIB: /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib/libz.tbd (found version "1.2.12")
-- Found PNG: /opt/homebrew/lib/libpng.dylib (found version "1.6.47")
-- Found HDF5: hdf5-shared (found version "1.14.6") found components: C HL
-- HDF5 Libraries: hdf5-shared
-- OpenMC C++ flags: -DH5Oget_info_by_idx_vers=1;-DH5O_info_t_vers=1
-- OpenMC Linker flags:
-- Submodule update
-- Did not find pugixml, will use submodule instead
-- Did not find fmt, will use submodule instead
-- {fmt} version: 11.0.2
-- Build type: RelWithDebInfo
-- Performing Test HAS_NULLPTR_WARNING
-- Performing Test HAS_NULLPTR_WARNING - Success
-- Performing Test arch_native_supported
-- Performing Test arch_native_supported - Success
-- Found xtensor: /opt/homebrew/share/cmake/xtensor (version 0.26.0)
-- Did not find Catch2, will use submodule instead
-- Performing Test HAVE_FLAG__ffile_prefix_map__Users_Nick_programs_openmc_vendor_Catch2__
-- Performing Test HAVE_FLAG__ffile_prefix_map__Users_Nick_programs_openmc_vendor_Catch2__ - Success
-- Configuring done (5.2s)
-- Generating done (0.1s)
-- Build files have been written to: /Users/Nick/programs/openmc/build
Now, when I run make, I receive the following error
[ 1%] Building CXX object vendor/fmt/CMakeFiles/fmt.dir/src/format.cc.o
[ 1%] Building CXX object vendor/fmt/CMakeFiles/fmt.dir/src/os.cc.o
[ 2%] Linking CXX static library ../../lib/libfmt.a
[ 2%] Built target fmt
[ 3%] Building CXX object vendor/pugixml/CMakeFiles/pugixml-static.dir/src/pugixml.cpp.o
[ 3%] Linking CXX static library ../../lib/libpugixml.a
[ 3%] Built target pugixml-static
[ 3%] Building CXX object CMakeFiles/libopenmc.dir/src/bank.cpp.o
In file included from /Users/Nick/programs/openmc/src/bank.cpp:5:
In file included from /Users/Nick/programs/openmc/include/openmc/simulation.h:7:
/Users/Nick/programs/openmc/include/openmc/mesh.h:11:10: fatal error: 'xtensor/xtensor.hpp' file not found
11 | #include "xtensor/xtensor.hpp"
| ^~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [CMakeFiles/libopenmc.dir/src/bank.cpp.o] Error 1
make[1]: *** [CMakeFiles/libopenmc.dir/all] Error 2
make: *** [all] Error 2
I ran brew install llvm cmake xtensor hdf5 python libomp libpng as suggested in the guide, but make cannot find xtensor for some reason. I’m a in a bit over my head, so some help would be appreciated!