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

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?

10 Answers

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.

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.

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 

On my system Ubuntu 16.04. I installed :

sudo apt install libopenmpi-dev 

after I used mpiCC to compile and it works

As suggested above the inclusion of

/usr/lib/openmpi/include 

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

Debian appears to include the following:

• mpiCC.openmpi
• mpic++.openmpi
• mpicc.openmpi
• mpicxx.openmpi
• mpif77.openmpi
• mpif90.openmpi

I'll test symlinks of each for mpic, etc., and see if that helps the likes of HDF5-openmpi enabled find mpi.h.

Take that back Debian includes symlinks via their alternatives system and it still cannot find the proper paths between HDF5 openmpi packages and mpi.h referenced in the H5public.h header.

On Ubuntu 18.04 I had to install:

sudo apt install lam4-dev 

On Fedora:

dnf install openmpi-devel 

On Mac 12.2, I installed with brew install openmpi. The header file is under /opt/homebrew/Cellar/open-mpi/x.x.x/include.

once you have mpi installed:

$ sudo apt install mpich

see where the library is installed, each case is different:

$ mpicc -show

in my case: (Ubuntu 20.0)

and add...

#include </usr/lib/x86_64-linux-gnu/openmpi/include/openmpi>

:-)