Do you run your program on one node with 20 processes, and the result is correct except the time is slower? If yes, then it seems only one CPU of the node is used, which is weird. --Junchao Zhang On Wed, Nov 26, 2014 at 1:22 PM, Shuchi Yang <[email protected]> wrote:

I am doing CFD simulation. With MPI, I can split the computational domain to different parts so that each process works on different part. In this case, we can reduce the total computational time.

When I tried to run at another different system, it looks all the cpu are working on the whole computational domain. It looks like every CPU is working on the whole computational domain so that the computational efficiency is very low.

On Wed, Nov 26, 2014 at 11:45 AM, Junchao Zhang <[email protected]> wrote:

...

I guess it is not an MPI problem. When you say "every CPU works on all the data", you need a clear idea of what is the data decomposition in your code.

--Junchao Zhang

On Wed, Nov 26, 2014 at 11:28 AM, Shuchi Yang <[email protected]> wrote:

...

Thanks for your reply. I am trying it in the way you mentioned. But I met one problem is that on my original machine, I can run the code with 20 CPUs so that each CPU works on part of the job. But at the new machine, it starts the process with 20 CPUS, but every CPU works on all the data, so that it looks like it is running 20 times the job at same time. Is that because of MPI problem? Thanks,

Shuchi

On Wed, Nov 26, 2014 at 9:50 AM, Junchao Zhang <[email protected]> wrote:

...

You can copy MPI libraries installed on the Ubuntu machine to the Suse machine, then add that path to LD_LIBRARY_PATH on the Suse.

--Junchao Zhang

On Wed, Nov 26, 2014 at 9:55 AM, Shuchi Yang <[email protected]> wrote:

...

I met some problem. The question is that I compile a fortran code at ubuntu, but I need run the code at Suse Linux, I was always told * error while loading shared libraries: libmpifort.so.12: cannot open shared object file: No such file or directory*

Furthermore, will this be a problem, I mean, if I compile the code with mpich-gcc and run the code at another type of Linux?

Thanks,

Shuchi

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