[petsc-users] petscviewerbinaryread

[Frederik Treue]

Hi guys,

is petscviewerbinaryread working? The examples given at the webpage
either fails with out of memory error issues (ex65 and ex65dm) or
doesn't compile (ex61) for me?

Oddly I have problems only when trying to use mpi. My code:

ierr=DMDACreate1d(PETSC_COMM_WORLD,DMDA_BOUNDARY_GHOSTED,156,1,1,PETSC_NULL,&da);CHKERRQ(ierr);

ierr=DMCreateGlobalVector(da,&ReRead);CHKERRQ(ierr);

ierr=VecAssemblyBegin(ReRead);CHKERRQ(ierr);
ierr=VecAssemblyEnd(ReRead);CHKERRQ(ierr);

double *workarray=(double*)malloc(156*sizeof(double));

ierr = VecGetArray(ReRead,&workarray); CHKERRQ(ierr);

ierr=PetscViewerBinaryOpen(PETSC_COMM_WORLD,"./testvector",FILE_MODE_READ,&fileview);CHKERRQ(ierr);

ierr=PetscViewerBinaryRead(fileview,&dummy,1,PETSC_SCALAR);CHKERRQ(ierr);

ierr=PetscViewerBinaryRead(fileview,(void*)workarray,156,PETSC_SCALAR);CHKERRQ(ierr);
printf("TEST: %g\n",workarray[144]);
ierr=VecRestoreArray(ReRead,&workarray);

VecView(ReRead,PETSC_VIEWER_DRAW_WORLD);

This works fine as long as I'm on a single processor. The file read also
works on mpi with 2 processors, as evidenced by the result of the printf
statement (which gives the right result from both processors). However
the VecView statement fails with "Vector not generated from a DMDA!".
Why?

And second question: How do I generalize to 2d? Can I give a 2d array to
PetscViewerBinaryRead and expect it to work? And how should it be
malloc'ed? Or does one give a 1d array to PetscViewerBinaryRead and let
VecRestoreArray do the rest? Or what?

/Frederik Treue