Classification: UNCLASSIFIED Caveats: NONE Sounds like there is an issue in transferring the value to the core that is printing out your timestep data.
I doubt that the problem is MPI_COMM_WORLD, that controls the communication description and shouldn't affect the values transferred. You will want to look at your MPI_Reduce and MPI_Send calls to make sure that everything is ending up on the correct cores. Keep in mind that with MPI each process has its own local copy of a value, so changes on one core don't affect any others. -Andrew -----Original Message----- From: users [mailto:users-boun...@open-mpi.org] On Behalf Of Muhammad Ashfaqur Rahman Sent: Saturday, February 14, 2015 6:10 AM To: Open MPI Users Subject: Re: [OMPI users] prob in running two mpi merged program (UNCLASSIFIED) Dear Andrew Burns, Many thanks to you for providing steps to check my programs. The combined program is now running parallel. But the values from one of the program are appearing as NaN. The possible reason may be the MPI_COMM_WORLD. I am still trying to sort it out. I have attached here the related files and outputs for your kind suggestions: Regards Ashfaq On Fri, Feb 6, 2015 at 6:35 PM, Burns, Andrew J CTR (US) <andrew.j.burns35....@mail.mil> wrote: Classification: UNCLASSIFIED Caveats: NONE The placing of clminitialize and clmstop feel a little awkward, but it doesn't look like they would break the program. If you were calling MPI_Init more than once it would throw an error and if Finalize were called early in clmstop the only serial section would be the deallocation. One other thought is to ensure that you are properly launching the program as multicore. The command should be similar to as follows (where NPROCS is the number of cores being used): mpirun -n NPROCS ./program If you were to launch the program with simply "./program" it would run as serial. It would also run as serial if you were to call "mpirun ./program" since no number of processes are specified. If the program is properly launched in parallel and then converts to serial, you should be able to track down the location where this happens by inserting some core polling similar to the following pseudocode: for (i = 0; i < numprocs; ++i) { if (i = coreid) { print("core ", id, " out of ", numprocs) } MPI_Barrier() } You will want to check all of the calls inside the main loop to ensure that none of them call finalize. -Andrew Burns -----Original Message----- From: users [mailto:users-boun...@open-mpi.org] On Behalf Of Muhammad Ashfaqur Rahman Sent: Friday, February 06, 2015 9:50 AM To: Open MPI Users Subject: Re: [OMPI users] prob in running two mpi merged program (UNCLASSIFIED) Dear Andrew Burns, Many thanks for your correct understanding and descriptive suggestion. I have now changed the FLAGS of one program for not to take any MPI tags, i.e., switched off MPI. And then for the another set kept open for MPI options. After that call the MPI_Initialize to the beginning of Main program (aadmn.F here) and call MPI_Finalize containing program (clmstop.F90 here) at the end part. After compilation it is still serial. I have attached here the FILES containing MPI calling and Makefile for your kind consideration. Regards Ashfaq On Thu, Feb 5, 2015 at 8:25 PM, Burns, Andrew J CTR (US) <andrew.j.burns35....@mail.mil> wrote: Classification: UNCLASSIFIED Caveats: NONE Okay, I think I may get what's going on. I think you're calling one mpi capable program from within another mpi program. What you have to do is assume that the program that is being called already had MPI_Init called and that MPI_Finalize will be called after the program returns. Example (pseudocode for brevity): int main() { MPI_Init(); int x; int p2result = Program2(x, comm); MPI_Bcast(p2result, comm); MPI_Finalize(); } int Program2(int x, MPI_Comm comm) { int returnval; MPI_AllReduce(&returnval, x, comm); return returnval; } If the second program were to be: int Program2(int x, MPI_Comm comm) { MPI_Init(); int returnval; MPI_AllReduce(&returnval, x, comm); return returnval; MPI_Finalize() } The program would return to serial when MPI_Finalize is first called, potentially throwing several errors. -Andrew Burns -----Original Message----- From: users [mailto:users-boun...@open-mpi.org] On Behalf Of Muhammad Ashfaqur Rahman Sent: Wednesday, February 04, 2015 3:42 PM To: Open MPI Users Subject: Re: [OMPI users] prob in running two mpi merged program (UNCLASSIFIED) Dear Andrew Burns, Thank you for your ideas. Your guess is partly correct, I am trying to merge two sets of programs into one executable and then run in mpi. As per your suggestion, I have omitted the MPI_Finalize from of one set. And also commented the MPI_Barrier in some parts. But still it is serial. For your idea: attached here Makefile. Regards Ashfaq On Tue, Feb 3, 2015 at 6:26 PM, Burns, Andrew J CTR (US) <andrew.j.burns35....@mail.mil> wrote: Classification: UNCLASSIFIED Caveats: NONE If I could venture a guess, it sounds like you are trying to merge two separate programs into one executable and run them in parallel via MPI. The problem sounds like an issue where your program starts in parallel but then changes back to serial while the program is still executing. I can't be entirely sure without looking at the code itself. One guess is that MPI_Finalize is in the wrong location. Finalize should be called to end the parallel section and move the program back to serial. Typically this means that Finalize will be very close to the last line of the program. It may also be possible that with the way your program is structured, the effect is effectively serial since only one core is processing at any given moment. This may be due to extensive use of barrier or similar functions. Andrew Burns Lockheed Martin Software Engineer 410-306-0409 ARL DSRC andrew.j.bur...@us.army.mil andrew.j.burns35....@mail.mil -----Original Message----- From: users [mailto:users-boun...@open-mpi.org] On Behalf Of Ralph Castain Sent: Tuesday, February 03, 2015 9:05 AM To: Open MPI Users Subject: Re: [OMPI users] prob in running two mpi merged program I'm afraid I don't quite understand what you are saying, so let's see if I can clarify. You have two fortran MPI programs. You start one using "mpiexec". You then start the other one as a singleton - i.e., you just run "myapp" without using mpiexec. The two apps are attempting to execute an MPI_Connect/accept so they can "join". Is that correct? You mention MPICH in your statement about one of the procs - are you using MPICH or Open MPI? If the latter, which version are you using? Ralph On Mon, Feb 2, 2015 at 11:35 PM, Muhammad Ashfaqur Rahman <ashfaq...@gmail.com> wrote: Dear All, Take my greetings. I am new in mpi usage. I have problems in parallel run, when two fortran mpi programs are merged to one executable. If these two are separate, then they are running parallel. One program has used spmd and another one has used mpich header directly. Other issue is that while trying to run the above mentioned merged program in mpi, it's first started with separate parallel instances of same step and then after some steps it becomes serial. Please help me in this regards Ashfaq Ph.D Student Dept. of Meteorology _______________________________________________ users mailing list us...@open-mpi.org Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users Link to this post: http://www.open-mpi.org/community/lists/users/2015/02/26264.php Classification: UNCLASSIFIED Caveats: NONE _______________________________________________ users mailing list us...@open-mpi.org Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users Link to this post: http://www.open-mpi.org/community/lists/users/2015/02/26266.php Classification: UNCLASSIFIED Caveats: NONE _______________________________________________ users mailing list us...@open-mpi.org Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users Link to this post: http://www.open-mpi.org/community/lists/users/2015/02/26293.php Classification: UNCLASSIFIED Caveats: NONE _______________________________________________ users mailing list us...@open-mpi.org Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users Link to this post: http://www.open-mpi.org/community/lists/users/2015/02/26300.php Classification: UNCLASSIFIED Caveats: NONE
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