Arch Linux User Repository

The default CFLAGS/CXXFLAGS set in the /etc/makepkg.conf are currently

-march=x86-64 -mtune=generic -O2 -pipe -fno-plt

With this it will sort of run on every x86-64 (amd64) machine.

Usually build tools like GNU Autotools, CMake etc. will automatically include the values set in the environment variables like that in the build process. OpenFOAM with this special WMake build tool apparently doesn't do so.

For my Desktop PC I changed the makepkg.conf CFLAGS/CXXFLAGS line to

-march=znver2 -mtune=znver2 -O3 -pipe -fno-plt

so it enables all the AVX/AVX2/FMA3 SIMD instructions when building packages which is for my Zen 2 AMD CPU and that will improve the performance for scientific computations a lot.

Can check and see what the default flags for compilation with GCC are with

gcc -Q --help=target | grep "march\|mtune\|sse\|avx\|fma"

It basically sets back to very basic Pentium 4 era SSE2 SIMD instructions and use none the instruction set extensions "recent" CPUs have implemented.

https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html

@daren Will the binaries be still compatible with old machines after applying your changes?

The CXXFLAGS environment variable set in makepkg.conf don't seem to be picked up in the build system.

How could these be used so it doesn't create binaries that only contain 20 year old amd64 instructions? There's no -march flag whatsoever in the compile commands.

Edit: Setting this in the build() function before building works.

  # Apply CFLAGS and CXXFLAGS to compile options
  sed -e "s/\(cOPT.*=\)/\1 ${CFLAGS}/g" \
      -i ${srcdir}/${_distpkgname}-${pkgver}/wmake/rules/linux64Gcc/cOpt
  sed -e "s/\(c++OPT.*=\)/\1 ${CXXFLAGS}/g" \
      -i ${srcdir}/${_distpkgname}-${pkgver}/wmake/rules/linux64Gcc/c++Opt

@ng0177 Well, we can't help you if there is no log or output. I have no idea what the MPI error is.

@ng0177 Manjaro is not supported here. Install Arch Linux.

V7 builds fine on a Manjaro Desktop but on a Manjaro Laptop it fails w/ an MPI error. Any ideas?

paraview-opt can also be downloaded from arch4edu now.

@jancici the bug is already known (https://bugs.archlinux.org/task/61594?project=5&string=paraview). A possible workaround is to install the paraview-opt package which is present in AUR which installa paraview in /opt avoiding the conflict.

I have installed freecad which requires opencascade and that one require vtk. Installing openfoam I get error when files for conflicts:

error: failed to commit transaction (conflicting files)
paraview: /usr/lib/python3.7/site-packages/vtk.py exists in filesystem (owned by vtk)
paraview: /usr/lib/python3.7/site-packages/vtkmodules/__init__.py exists in filesystem (owned by vtk)
...

should I write it to paraview as bug? thanks

@archmkr You can download the pre-built binaries from arch4edu.

Direct link: https://mirrors.tuna.tsinghua.edu.cn/arch4edu/x86_64/openfoam-6.20190304-1-x86_64.pkg.tar.xz