How to create and run MPI projects in CLion

1. Download and install MPI from Microsoft Website. You need to download both msmpisetup.exe and msmpisdk.msi.

Note that you shouldn't have spaces or cyrillic characters in path to MPI installation.

2. Open Windows Terminal and try running mpiexec:

Microsoft MPI Startup Program [Version 10.1.12498.18]

...

If the mpiexec command isn't recognised by your system try restarting your PC and check if MPI system variables are installed correctly:

Name	Value
MSMPI_BENCHMARKS	path_to_mpi\Benchmarks\
MSMPI_BIN	path_to_mpi\Bin\
MSMPI_INC	path_to_mpi\SDK\Include\
MSMPI_LIB32	path_to_mpi\SDK\Lib\x86\
MSMPI_LIB64	path_to_mpi\SDK\Lib\x64\

And path_to_mpi\Bin\ path is added to Path variable.

To view system variables open Windows Search -> Input "Variables" -> Click on "Edit the system environment variables" -> Click on "Environemnt Variables on "System Properties" Window.

path_to_mpi is a path to your Microsoft MPI installation.

3. Open CLion and create new C++ Executable Project.

4. Open CMakeLists.txt where you should see something like this: (MY_PROJECT is project name)

cmake_minimum_required(VERSION 3.20)
project(MY_PROJECT)

set(CMAKE_CXX_STANDARD 14)

add_executable(MY_PROJECT main.cpp)

5. Add MPI Package and MPI Library to project

cmake_minimum_required(VERSION 3.20)
project (MY_PROJECT)

set(CMAKE_CXX_STANDARD 14)

# Add MPI Package to Project
find_package(MPI REQUIRED)

add_executable(MY_PROJECT main.cpp)
# Add libraries for code completion and compiling
target_link_libraries(MY_PROJECT PUBLIC MPI::MPI_CXX)

6. Add following run configurations:

1) CMake Application

Property	Value
Name	Compile
Tagret	MY_PROJECT
Executable	MY_PROJECT

IMPORTANT! Replace MY_PROJECT with the name of your project!

2) Shell Script

Property	Value
Name	2 Cores
Execute	Script text
Script text	mpiexec -n 2 ./cmake-build-debug/MY_PROJECT
Working directory	project_directory/MY_PROJECT
Execute in the terminal	true

Add more shell scripts for number of cores you would like to use while executing your project. Replace number 2 in Name and Script text properties with number of cores you would like to use.

MY_PROJECT is a name of .exe file in ./cmake-build-debug folder.

7. Add following code to main.cpp:

#include <mpi.h>
#include <cstdio>

int main(int argc, char** argv) {
	// Initialize the MPI environment
	MPI_Init(NULL, NULL);

	// Get the number of processes
	int world_size;
	MPI_Comm_size(MPI_COMM_WORLD, &world_size);

	// Get the rank of the process
	int world_rank;
	MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);

	// Get the name of the processor
	char processor_name[MPI_MAX_PROCESSOR_NAME];
	int name_len;
	MPI_Get_processor_name(processor_name, &name_len);

	// Print off a hello world message
	printf("Hello world from processor %s, rank %d out of %d processors\n",
		   processor_name, world_rank, world_size);

	// Finalize the MPI environment.
	MPI_Finalize();
}

8. Setup CMake "Release" configuration. Go to Settings -> Build, Execution, Deployment -> CMake. Click on "Plus" sign and a new "Release" configuration should be created. Click on "OK" or "Apply".

9. Select "Release" under "Configurations" dropdown.

10. Run Compile configuration before executing any of X Cores configurations.

If you are getting an error "Cannot start process, the working directory '../cmake-build-release' does not exist" then RMC on your project folder and select "Reload CMake Project".