Actually, MPICH is incorrect here. NULL objects are an error unless specifically permitted.
Bill On Sep 15, 2014, at 1:08 PM, Barry Smith <[email protected]> wrote: > > 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 >
