Matt, I ran with OpenMPI and got exactly the error you’d expect and what they reported "An error occurred in MPI_Type_size”. A simple use of the debugger would reveal where it happened. I suspect that MPICH is more generous when you call MPI_Type_size() with a null type, perhaps it just gives a size of zero.
I hunted around on the web and could not find a definitive statement of what MPI_Type_size() should do when passed an argument of a null datatype. Barry On Sep 15, 2014, at 4:40 AM, Matthew Knepley <[email protected]> wrote: > On Sun, Sep 14, 2014 at 8:36 PM, Barry Smith <[email protected]> wrote: > > Pierre, > > Thanks for reporting this, it is, indeed our bug. In petsclog.h we have > macros for the various MPI calls in order to log their usage, for example, > > #define > MPI_Scatter(sendbuf,sendcount,sendtype,recvbuf,recvcount,recvtype,root,comm) \ > ((petsc_scatter_ct++,0) || > PetscMPITypeSize(&petsc_recv_len,recvcount,recvtype) || > MPI_Scatter(sendbuf,sendcount,sendtype,recvbuf,recvcount,recvtype,root,comm)) > > but PetscMPITypeSize() simply called MPI_Type_size() which generated an MPI > error for MPI_DATATYPE_NULL > > PETSC_STATIC_INLINE PetscErrorCode PetscMPITypeSize(PetscLogDouble > *buff,PetscMPIInt count,MPI_Datatype type) > { > PetscMPIInt mysize; return (MPI_Type_size(type,&mysize) || ((*buff += > (PetscLogDouble) (count*mysize)),0)); > } > > What error did you get? Why did I not get this error when I ran it? I ran > with MPICH 3.0.4 since that was the one I had compiled for C++. > > Matt > > In the branch barry/fix-usage-with-mpidatatypenull I have added a check for > this special case and avoid the MPI_Type_size() call. I will put this branch > into next and if all tests pass it will be merged into maint and master and > be in the next patch release. > > Thank you for reporting the problem. > > Barry > > Barry still thinks MPI 1.1 is the height of HPC computing :-( > > > > On Sep 14, 2014, at 4:16 PM, Pierre Jolivet <[email protected]> wrote: > > > Hello, > > Could you please explain to me why the following example is not working > > properly when <petsc.h> (from master, with OpenMPI 1.8.1) is included ? > > > > $ mpicxx in-place.cpp -I$PETSC_DIR/include > > -I$PETSC_DIR/$PETSC_ARCH/include -L$PETSC_DIR/$PETSC_ARCH/lib -lpetsc > > $ mpirun -np 2 ./a.out > > Done with the scatter ! > > 0 0 0 0 (this line should be filled with 0) > > 1 1 1 1 (this line should be filled with 1) > > Done with the gather ! > > > > $ mpicxx in-place.cpp -I$PETSC_DIR/include > > -I$PETSC_DIR/$PETSC_ARCH/include -L$PETSC_DIR/$PETSC_ARCH/lib -lpetsc > > -DPETSC_BUG > > $ mpirun -np 2 ./a.out > > [:3367] *** An error occurred in MPI_Type_size > > [:3367] *** reported by process [4819779585,140733193388032] > > [:3367] *** on communicator MPI_COMM_WORLD > > [:3367] *** MPI_ERR_TYPE: invalid datatype > > [:3367] *** MPI_ERRORS_ARE_FATAL (processes in this communicator will now > > abort, > > [:3367] *** and potentially your MPI job) > > > > Thank you for looking, > > Pierre > > > > <in-place.cpp> > > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener
