[OMPI users] try to understand heat equation 2D mpi version

Hello, i'm studying the parallelized version of a solving 2D heat equation code in order to understand cartesian topology and the famous "MPI_CART_SHIFT". Here's my problem at this part of the code :

Re: [OMPI users] Question about MPI_Barrier

I got it. You're right, it might not related to MPI. I need to figure out what's the possible reason for it. Again, thanks for your help. Linbao On Thu, Oct 21, 2010 at 12:06 PM, Eugene Loh wrote: > My main point was that, while what Jeff said about the short-comings of

Re: [OMPI users] Question about MPI_Barrier

My main point was that, while what Jeff said about the short-comings of calling timers after Barriers was true, I wanted to come in defense of this timing strategy.  Otherwise, I was just agreeing with him that it seems implausible that commenting out B should influence the timing of A, but

Re: [OMPI users] Question about MPI_Barrier

Hi, Eugene, You said: " The bottom line here is that from a causal point of view it would seem that B should not impact the timings. Presumably, some other variable is actually responsible here." Could you explain it in more details for the second sentence. Thanks a lot. Linbao On Thu, Oct 21,

Re: [OMPI users] Question about MPI_Barrier

Thanks a lot. On Thu, Oct 21, 2010 at 9:21 AM, Jeff Squyres wrote: > Ah. The original code snipit you sent was: > > MPI::COMM_WORLD.Barrier(); > if if(rank == master) t1 = clock(); > "code A"; > MPI::COMM_WORLD.Barrier(); > if if(rank == master) t2 = clock(); > "code B"; >

Re: [OMPI users] Question about MPI_Barrier

Jeff Squyres wrote: Ah. The original code snipit you sent was: MPI::COMM_WORLD.Barrier(); if(rank == master) t1 = clock(); "code A"; MPI::COMM_WORLD.Barrier(); if(rank == master) t2 = clock(); "code B"; Remember that the time that individual processes exit barrier is not guaranteed to be

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

When you do a make can your add a V=1 to have the actual compile lines printed out. That will probably show you the line with -fno-directives-only in it. Which is odd because I think that option is a gcc'ism and don't know why it would show up in a studio build (note my build doesn't show

Re: [OMPI users] OpenMPI 1.4.2 with Myrinet MX, mpirun seg faults

On 10/20/2010 8:30 PM, Scott Atchley wrote: We have fixed this bug in the most recent 1.4.x and 1.5.x releases. Scott OK, a few more tests. I was using PGI 10.4 as the compiler. I have now tried OpenMPI 1.4.3 with PGI 10.8 and Intel 11.1. I get the same results in each case, mpirun seg

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

On 10/21/2010 10:18 AM, Jeff Squyres wrote: Terry -- Can you file relevant ticket(s) for v1.5 on Trac? Once I have more information and have proven it isn't due to us using old compilers or a compiler error itself. --td On Oct 21, 2010, at 10:10 AM, Terry Dontje wrote: I've reproduced

Re: [OMPI users] Question about MPI_Barrier

Ah. The original code snipit you sent was: MPI::COMM_WORLD.Barrier(); if if(rank == master) t1 = clock(); "code A"; MPI::COMM_WORLD.Barrier(); if if(rank == master) t2 = clock(); "code B"; Remember that the time that individual processes exit barrier is not guaranteed to be uniform (indeed, it

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

> I wonder if the error below be due to crap being left over in the > source tree. Can you do a "make clean". Note on a new checkout from > the v1.5 svn branch I was able to build 64 bit with the following > configure line: linpc4 openmpi-1.5-Linux.x86_64.32_cc 123 make clean Making clean

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

Terry -- Can you file relevant ticket(s) for v1.5 on Trac? On Oct 21, 2010, at 10:10 AM, Terry Dontje wrote: > I've reproduced Siegmar's issue when I have the threads options on but it > does not show up when they are off. It is actually segv'ing in > mca_btl_sm_component_close on an access

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

I've reproduced Siegmar's issue when I have the threads options on but it does not show up when they are off. It is actually segv'ing in mca_btl_sm_component_close on an access at address 0 (obviously not a good thing). I am going compile things with debug on and see if I can track this

Re: [OMPI users] Question about MPI_Barrier

Thanks for your suggestion. I am trying MPI_Wtime to see if there is any difference. Linbao On Thu, Oct 21, 2010 at 1:37 AM, jody wrote: > Hi > > I don't know the reason for the strange behaviour, but anyway, > to measure time in an MPI application you should use

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

On 10/21/2010 06:43 AM, Jeff Squyres (jsquyres) wrote: Also, i'm not entirely sure what all the commands are that you are showing. Some of those warnings (eg in config.log) are normal. The 32 bit test failure is not, though. Terry - any idea there? The test program is failing in MPI_Finalize

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

Also, i'm not entirely sure what all the commands are that you are showing. Some of those warnings (eg in config.log) are normal. The 32 bit test failure is not, though. Terry - any idea there? Sent from my PDA. No type good. On Oct 21, 2010, at 6:25 AM, "Terry Dontje"

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

I wonder if the error below be due to crap being left over in the source tree. Can you do a "make clean". Note on a new checkout from the v1.5 svn branch I was able to build 64 bit with the following configure line: ../configure FC=f95 F77=f77 CC=cc CXX=CC --without-openib --without-udapl

Re: [OMPI users] Question about MPI_Barrier

On Oct 20, 2010, at 5:51 PM, Storm Zhang wrote: > I need to measure t2-t1 to see the time spent on the code A between these two > MPI_Barriers. I notice that if I comment code B, the time seems much less the > original time (almost half). How does it happen? What is a possible reason > for it?

[OMPI users] some warnings and failures building and testing openmpi-1.5

Hi, I have built Open MPI 1.5 on SunOS Sparc with the Oracle/Sun Studio C compiler and gcc-4.2.0 in 32- and 64-bit mode. A small test program works, but I got some warnings and errors building and checking the installation as you can see below. Perhaps somebody knows how to fix these things and

Re: [OMPI users] segmentation fault in mpiexec (Linux, Oracle/Sun C)

Hi, thank you very much for your reply. > Can you remove the -with-threads and -enable-mpi-threads options from > the configure line and see if that helps your 32 bit problem any? I cannot build the package when I remove these options. linpc4 openmpi-1.5-Linux.x86_64.32_cc 189 head -8

Re: [OMPI users] Question about MPI_Barrier

Hi I don't know the reason for the strange behaviour, but anyway, to measure time in an MPI application you should use MPI_Wtime(), not clock() regards jody On Wed, Oct 20, 2010 at 11:51 PM, Storm Zhang wrote: > Dear all, > > I got confused with my recent C++ MPI