(--with-scalar-type=[real,complex], --with-precision=[single,double]) Depending upon how petsc is configured - PetscScalar can be either real4,real8,complex8. With most common usage - [i.e default build] PetscScalar is real8.
Earlier you claimed: MPI_ISEND(v_ast) worked with MPI_REAL but not MPI_REAL8. This sugested that v_ast was declared as real4 - not real8. Satish On Tue, 14 Apr 2009, Wee-Beng TAY wrote: > Hi, > > So when must I use PetscScalar, and when can I just use real(8)? This is > because most of my variables are in real(8), except for the Mat, Vec, required > in the solving of the linear eqn. Is there a rule? I initially thought they > are the same and if I remember correctly, it seems to work fine in PETSc2.3.3. > > My v_ast is now defined as: > > PetscScalar, allocatable :: u_ast(:,:), v_ast(:,:) > > allocate (u_ast(0:size_x+1,jsta_ext:jend_ext), STAT=status(1));allocate > (v_ast(0:size_x+1,jsta_ext:jend_ext), STAT=status(2)) > > if (status(1)/=0 .or. status(2)/=0) STOP "Cannot allocate memory" > > Thank you very much and have a nice day! > > Yours sincerely, > > Wee-Beng Tay > > > > Satish Balay wrote: > > And if v_ast() is used with PETSc - then it should be defined 'PetscScalar' > > > > and then you use MPI_ISEND(....,MPIU_SCALAR,...) > > > > Satish > > > > > > On Mon, 13 Apr 2009, Barry Smith wrote: > > > > > > > Where is your implicit none that all sane programmers begin their > > > Fortran > > > subroutines with? > > > > > > > > > On Apr 13, 2009, at 11:11 AM, Wee-Beng TAY wrote: > > > > > > > > > > Hi Satish, > > > > > > > > Compiling and building now worked without error. However, when I run, I > > > > get > > > > the error: > > > > > > > > 0 - MPI_ISEND : Datatype is MPI_TYPE_NULL > > > > [0] Aborting program ! > > > > [0] Aborting program! > > > > Error 323, process 0, host GOTCHAMA-E73BB3: > > > > > > > > The problem lies in this subroutine: > > > > > > > > subroutine v_ast_row_copy > > > > > > > > #include "finclude/petsc.h" > > > > #include "finclude/petscvec.h" > > > > #include "finclude/petscmat.h" > > > > #include "finclude/petscksp.h" > > > > #include "finclude/petscpc.h" > > > > #include "finclude/petscsys.h" > > > > > > > > !to copy data of jend row to others > > > > > > > > integer :: inext,iprev,istatus(MPI_STATUS_SIZE),irecv1,ierr,isend1 > > > > > > > > inext = myid + 1 > > > > iprev = myid - 1 > > > > > > > > if (myid == num_procs - 1) inext = MPI_PROC_NULL > > > > > > > > if (myid == 0) iprev = MPI_PROC_NULL > > > > > > > > CALL > > > > MPI_ISEND(v_ast(1,jend),size_x,MPI_REAL8,inext,1,MPI_COMM_WORLD,isend1,ierr) > > > > CALL > > > > MPI_IRECV(v_ast(1,jsta-1),size_x,MPI_REAL8,iprev,1,MPI_COMM_WORLD,irecv1,ierr) > > > > CALL MPI_WAIT(isend1, istatus, ierr) > > > > CALL MPI_WAIT(irecv1, istatus, ierr) > > > > > > > > end subroutine v_ast_row_copy > > > > > > > > > > > > I copied this subroutine from the RS6000 mpi manual and it used to work. > > > > I > > > > wonder if this is a MPI or PETSc problem? Strange because I already > > > > specify > > > > the type to be MPI_REAL8. However changing to MPI_REAL solves the > > > > problem. > > > > > > > > If this is a MPI problem, then you can just ignore it. I'll check it in > > > > some > > > > MPI forum. > > > > > > > > > > > > Thank you very much and have a nice day! > > > > > > > > Yours sincerely, > > > > > > > > Wee-Beng Tay
