<div dir="ltr">Hi,<br><br>I am trying to write a PETSc program in FORTRAN90 where I need to update a single value in a global distributed array. I know the global coordinates of the position that needs to be updated in the global array but I cannot get the mapping from the local vector correct. In this case, I am working on a domain with global dimensions [arraysize(1),arraysize(2),arraysize(3)] and I want to alter a single point in the global distributed array, uGLOBAL, at the global position [arraysize(1)/2-1,arraysize(2)-1,3]. I cannot seem to be able to do this... what am I doing wrong?<br>
<br>...<br>DA da<br>Vec uGLOBAL, uLOCAL, tmp<br>PetscErrorCode ierr<br>PetscScalar, pointer :: xx<br>PetscInt rank, source_rank, i,j,k, row<br><br clear="all">....<br><br>call MPI_Comm_rank( PETSC_COMM_WORLD, rank, ierr )<br>
call DACreate3d( PETSC_COMM_WORLD, DA_NONPERIODIC, DA_STENCIL_BOX, &<br> arraysize(1), arraysize(2), arraysize(3), PETSC_DECIDE, &<br> PETSC_DECIDE, PETSC_DECIDE, 1, 5, PETSC_NULL_INTEGER, &<br>
PETSC_NULL_INTEGER, PETSC_NULL_INTEGER, da, ierr)<br>call DACreateGlobalVector( da, pNOW, ierr )<br>call DAGetCorners( da, xs, ys, zs, xl, yl, zl, ierr )<br><br> do i = xs,xs+xl-1<br> if ( i.eq.arraysize(1)/2-1 ) then<br>
src_loc(1) = i<br> do j = ys,ys+yl-1<br> if ( j.eq.arraysize(2)/2-1 ) then<br> src_loc(2) = j<br> do k = zs,zs+zl-1<br> if ( k.eq.3 ) then<br>
src_loc(2) = j<br> source_rank = rank<br> endif<br> enddo<br> endif<br> enddo<br> endif<br> enddo<br><br>call DAGetLocalVector( da, uLOCAL, ierr )<br>
call VecGetArrayF90( uLOCAL, xx, ierr )<br><br>if ( rank.eq.source_rank ) then<br> row = 15<br> xx(row) = pressure<br>endif<br><br>call VecRestoreArrayF90( uLOCAL, xx, ierr )<br>call DALocalToGlobal( da, uLOCAL, ADD_VALUES, uGLOBAL, ierr )<br>
call DARestoreLocalVector( da, uLOCAL, ierr )<br><br><br>Any help would be greatly appreciated. Is there a way to directly access the global distributed array (uGLOBAL) instead of working through the intermediate local array (uLOCAL)? I have tried the approach<br>
<br>call DAVecGetArray( da, uGLOBAL, xx, ierr )<br>xx = ....<br>call DAVecRestoreArray( da, uGLOBAL, xx, ierr )<br><br>Unfortunately, the compile always fails with the message that the DAVecRestoreArray function cannot be found.<br>
<br>Thank you,<br>Mark<br><br>-- <br>Mark Patrick Cheeseman<br><br>Computational Scientist<br>KSL (KAUST Supercomputing Laboratory)<br>Building 1, Office #126<br>King Abdullah University of Science & Technology<br>Thuwal 23955-6900<br>
Kingdom of Saudi Arabia<br> <br>EMAIL : <a href="mailto:mark.cheeseman@kaust.edu.sa">mark.cheeseman@kaust.edu.sa</a><br>PHONE : +966 (2) 808 0221 (office)<br> +966 (54) 470 1082 (mobile)<br>SKYPE : mark.patrick.cheeseman<br>
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