[CMake] FindMPI - Intel MPI on Windows

[Michel Lestrade]

The FindMPI module does not seem to work on Windows with the Intel MPI 
libraries. I am trying (unsuccessfully) to compile parmetis and since I 
am new to CMake, I tried to reduce the problem I am experiencing to the 
simplest possible example (attached).

I have the latest (12.1) Intel Compiler installed and the Intel MPI 
wrappers are in the system PATH. From my command-line environment, I can 
easily compile hello.c with the mpicc wrapper, using either cl.exe or 
icl.exe as the underlying compiler.

However, FindMPI always reports the following (cmake -G"NMake Makefiles" 
-DWIN32=TRUE):

-- Could NOT find MPI_C (missing:  MPI_C_LIBRARIES)
-- Could NOT find MPI_CXX (missing:  MPI_CXX_LIBRARIES)
CMake Error at CMakeLists.txt:7 (message):
   mpi is not found

The comments of FindMPI suggest a few solutions to this (such as 
defining MPI_C_COMPILER or MPI_C_LIBRARIES and MPI_C_INCLUDE_PATH) but I 
have not been able to make them work. I am wondering what is the best 
way to work around the problem ....

As I said, very new to CMake but I wonder if _MPI_PREFIX_PATH could use 
fixing. For Intel MPI, the path is usually stored in 
"%I_MPI_ROOT%%ARCH_PATH_MPI%" rather than the registry.

Thanks,

Michel Lestrade
-------------- next part --------------
/* C Example */
#include <stdio.h>
#include <mpi.h>


int main (argc, argv)
     int argc;
     char *argv[];
{
  int rank, size;

  MPI_Init (&argc, &argv);	/* starts MPI */
  MPI_Comm_rank (MPI_COMM_WORLD, &rank);	/* get current process id */
  MPI_Comm_size (MPI_COMM_WORLD, &size);	/* get number of processes */
  printf( "Hello world from process %d of %d\n", rank, size );
  MPI_Finalize();
  return 0;
}
-------------- next part --------------
cmake_minimum_required(VERSION 2.8)
project(hello)

# Search for MPI.
include(FindMPI)
if(NOT MPI_FOUND)
  message(FATAL_ERROR "mpi is not found")
endif()
#set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")

target_link_libraries(${MPI_LIBRARIES})
set_target_properties(hello PROPERTIES LINK_FLAGS "${MPI_LINK_FLAGS}")