Incorrect MPI configuration

[mcopik]

Hi!

On my system, the build configuration could not detect MPI installation automatically:

/usr/bin/mpic++ --showme     
g++ -I/usr/lib/x86_64-linux-gnu/openmpi/include/openmpi -I/usr/lib/x86_64-linux-gnu/openmpi/include -pthread -L/usr/lib/x86_64-linux-gnu/openmpi/lib -lmpi_cxx -lmpi

Thus, I inspected the provided config files and the CMakeLists.txt file to figure out the configuration:

set(CMAKE_CXX_FLAGS "-I/usr/lib/x86_64-linux-gnu/openmpi/include -pthread -I/usr/lib/x86_64-linux-gnu/openmpi/include/openmpi/" CACHE STRING ""
set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} -L/usr/lib/x86_64-linux-gnu/openmpi/lib -lmpi_cxx -lmpi" CACHE STRING "")

However, this generates incorrect linking step:

/usr/bin/c++  -I/usr/lib/x86_64-linux-gnu/openmpi/include -pthread -I/usr/lib/x86_64-linux-gnu/openmpi/include/openmpi/     -Wall -Wextra  -O3 -ffast-math   -L/usr/lib/x86_64-linux-gnu/openmpi/lib -lmpi_cxx -lmpi CMakeFiles/kripke.exe.dir/src/kripke.cpp.o  -o bin/kripke.exe  lib/libRAJA.a lib/libkripke.a lib/libRAJA.a -ldl

Since linking flags are included before static libraries, the paths are never resolved. The correct approach would be to paste additional linking options at the end of this command.

Furthermore, wouldn't it be simpler to use the default CMake module to provide MPI paths?

find_package(MPI REQUIRED)
include_directories(${MPI_C_INCLUDE_PATH})
SET(MPI_INCLUDE_PATH ${MPI_C_INCLUDE_PATH})
SET(MPI_LINK_FLAGS ${MPI_C_LIBRARIES})

[rchen20]

Hi @mcopik, sorry for not getting back to you sooner. Thanks for the heads up on this. This should already be handled by setting the following variables in the host-config file:

set(ENABLE_MPI On CACHE BOOL "")
set(ENABLE_MPI_WRAPPER Off CACHE BOOL "")

ENABLE_MPI=On should perform the correct find_package() that you suggested. Let me know if this works for you.