fatal error: mpi.h: No such file or directory #include <mpi.h>

when I compile my script with only

#include <mpi.h>

it tells me that there is no such file or directory. But when i include the path to mpi.h as

#include "/usr/include/mpi/mpi.h"

(the path is correct) it returns:

In file included from /usr/include/mpi/mpi.h:2087:0,
                 from lbm.cc:7:
/usr/include/mpi/openmpi/ompi/mpi/cxx/mpicxx.h:35:17: fatal error: mpi.h: No such file or directory
 #include "mpi.h"
                 ^
compilation terminated.

Anyone know how to fix this?

Solution 1:

The problem is almost certainly that you're not using the MPI compiler wrappers. Whenever you're compiling an MPI program, you should use the MPI wrappers:

C - mpicc
C++ - mpiCC, mpicxx, mpic++
FORTRAN - mpifort, mpif77, mpif90

These wrappers do all of the dirty work for you of making sure that all of the appropriate compiler flags, libraries, include directories, library directories, etc. are included when you compile your program.

Solution 2:

On my system, I was just missing the Linux package.

sudo apt install libopenmpi-dev
pip install mpi4py

(example of something that uses it that is a good instant test to see if it succeeded)

Succeded.

Solution 3:

You can execute:

$ mpicc -showme

result :

gcc -I/Users/<USER_NAME>/openmpi-2.0.1/include -L/Users/<USER_NAME>/openmpi-2.0.1/lib -lmp

This command shows you the necessary libraries to compile mpicc

Example:

$ mpicc -g  -I/Users/<USER_NAME>/openmpi-2.0.1/include -o [nameExec] [objetcs.o...] [program.c] -lm


$ mpicc -g  -I/Users/<USER_NAME>/openmpi-2.0.1/include -o example file_object.o my_program.c otherlib.o -lm

this command generates executable with your program in example, you can execute :

$ ./example

Solution 4:

On my system Ubuntu 16.04. I installed :

sudo apt install libopenmpi-dev

after I used mpiCC to compile and it works

Solution 5:

As suggested above the inclusion of

/usr/lib/openmpi/include

in the include path takes care of this (in my case)