Using MPI in MEX function

I am trying to run parallel code which is designed in the following way: I launch multiple MPI processes where only one of them (master) calls matlab script which further calls mex function in which I want to set-up MPI communication with the rest of the processes launched at the beginning. However, I am getting a MPI runtime error:

It looks like MPI_INIT failed for some reason; your parallel process is
likely to abort.  There are many reasons that a parallel process can
fail during MPI_INIT; some of which are due to configuration or environment
problems.  This failure appears to be an internal failure; here's some
additional information (which may only be relevant to an Open MPI
developer):

ompi_mpi_init: ompi_rte_init failed
--> Returned "(null)" (-43) instead of "Success" (0)

Does anybody have experience with similar approach? Is it possible to use MEX function and MPI together? I am using openmpi-2.0.0 and R2014b

The Matlab/C/Mex code is here: https://github.com/goghino/matlabMpiC

Answer 1

[Juraj]

THIS APPROACH DOES NOT WORK!!!!!

https://www.mail-archive.com/[e-mail]//msg30088.html

The blocker is that a child cannot call MPI_Init() if its parent already called MPI_Init()

Fortunatly, there are some options (which I have not tried):-)

1) MPI_Comm_spawn matlab

master can MPI_Comm_spawn() matlab, and then matlab can merge the parent communicator, and communicate to master and slaves

(Merging communicators: https://stackoverflow.com/questions/24806782/mpi-merge-multiple-intercoms-into-a-single-intracomm