openfoam: Add *-mpi wrappers for all bins that use libPstream.so

* Ensure correct mpirun is used and right number of processes

openfoam.nix

@@ -34,7 +34,8 @@ stdenv.mkDerivation rec {
   '';
 
   # stick etc, bin, and platforms under lib/OpenFOAM-${version}
-  # fill bin proper up with wrappers to everything in platform/$WM_OPTIONS/bin that source etc/bashrc
+  # fill bin proper up with wrappers that source etc/bashrc for everything in platform/$WM_OPTIONS/bin
+  # add -mpi suffixed versions that calls proper mpirun for those with libPstream.so depencies too
   installPhase = ''
     echo "copying etc, bin, and platforms directories to $out/lib/OpenFOAM-${version}"
     mkdir -p "$out/lib/OpenFOAM-${version}"
@@ -43,6 +44,12 @@ stdenv.mkDerivation rec {
     for program in "$out/lib/OpenFOAM-${version}/platforms/$WM_OPTIONS/bin/"*; do
       makeWrapper "$program" "$out/bin/''${program##*/}" \
         --run "source \"$out/lib/OpenFOAM-${version}/etc/bashrc\""
+      if readelf -d "$program" | fgrep -q libPstream.so; then
+        makeWrapper "${openmpi}/bin/mpirun" "$out/bin/''${program##*/}-mpi" \
+          --run "[ -r processor0 ] || { echo \"Case is not currently decomposed, see decomposePar documentation\"; exit 1; }" \
+          --run "extraFlagsArray+=(-n \"\$(ls -d processor* | wc -l)\" \"$out/bin/''${program##*/}\" -parallel)" \
+          --run "source \"$out/lib/OpenFOAM-${version}/etc/bashrc\""
+      fi
     done
   '';