Setup JEMRIS for parallel processing (local)

[Michele Nicastro]

Dear Tony,

first of all, as researcher (Ph.D student), I express you all my admiration for the amazing work you did and you're keep doing implementing JEMRIS.

I'm writing to ask for support.

I tried to use pjemris on both Windows 10 and Ubuntu 18.04, without success unfortunately. I carefully followed your guide to enable parallel processing bu:

Windows 10:

- localhost(sequential) is still the only selectable computation setting.

Ubuntu 18.04:

- when I call pjemris from GUI, it get stucked as soon as the process bar appear. I called it from terminal and found a missing library error (libmpich.so.12). To solve this problem, I downgraded my mpich, libmpich-dev and libmpich12 versions to 3.2-6build1.

Now the problem I have is that pjemris is not able to see any slave:

Master Process: send MR sample (7825 spins) to 0 slave(s)

Do you have any advice for me to make it work?

Thank you in advance.

Kind regards,
Michele

[Tony Stoecker]

Dear Michele,

There are several issues running JEMRIS on windows. MPICH and also analytic calculations with the GiNaC library are not fully supported under windows. If you however went successfully through the MPICH installation, then parallel JEMRIS should work from the command window. (?) If this is the case, then some path settings might be unknown and therefore the "parallel" option is not shown in the Matlab GUI selection box. You have to check the code in JEMRIS_sim.m (lines 65-82) … but I strongly  suggest to run JEMRIS on linux (or Mac)

Unfortunately ubuntu 18.04 is not yet officially supported, but you can compile on your own, pulling the latest JEMRIS version from github. I just pushed a small change and now it should work with the standard MPI implementation (openmpi). Thus, you have to remove mpich again and install openmpi. Please compile using cmake. In short, the steps are:

> git clone https://github.com/JEMRIS/jemris.git

> cd jemris; mkdir build; cd build ; cmake .. 

> make

> sudo make install

Hope this helps!  If you have problems, send an email directly to me. Then I can provide you a precompiled package for ubuntu 18.04.

Tony

PS: I still have a small issue with open-mpi under Mac. Once this is resolved, I will put updates on the main jemris website.