[petsc-dev] VecScatter problem

[Mark Adams]

We have the subroutine below that scatters three vectors.  We have used
this code on many machines and it works fine but on one machine data does
not get scattered correctly. The first scatter looks OK, but it looks like
the other two are missing data.

Am I using this correctly?  Should we use VecGetArray in here instead of
just using the pointer used for construction? Is there a race condition
here that I'm missing?

Thanks,
Mark

subroutine scatter_to_xgc(a_ts,a_XX,a_n1,a_apar,a_phi,ierr)
  use petscts
  use sml_module,only:sml_mype
  use xgc_ts_module
  implicit none
  type(xgc_ts),intent(in)::a_ts
  Vec,intent(in)::a_XX
  real (kind=8),dimension(a_ts%nnode)::a_n1,a_apar,a_phi
  PetscErrorCode,intent(out)::ierr
  ! locals
  PetscInt,parameter::ione=1
  PetscScalar,dimension(a_ts%nnode)::n1,apar,phi
  Vec::xxvec(0:2)

  ! scatter solution back - n1
  n1 = a_n1
  call
VecCreateSeqWithArray(PETSC_COMM_SELF,ione,a_ts%nnode,n1,xxvec(0),ierr);CHKERRQ(ierr)
  call
VecScatterBegin(a_ts%from_petsc(0),a_XX,xxvec(0),INSERT_VALUES,SCATTER_FORWARD,ierr)

  ! scatter solution back - apar
  apar = a_apar
  call
VecCreateSeqWithArray(PETSC_COMM_SELF,ione,a_ts%nnode,apar,xxvec(1),ierr);CHKERRQ(ierr)
  call
VecScatterBegin(a_ts%from_petsc(1),a_XX,xxvec(1),INSERT_VALUES,SCATTER_FORWARD,ierr)

  ! scatter solution back - phi
  phi = a_phi
  call
VecCreateSeqWithArray(PETSC_COMM_SELF,ione,a_ts%nnode,phi,xxvec(2),ierr);CHKERRQ(ierr)
  call
VecScatterBegin(a_ts%from_petsc(2),a_XX,xxvec(2),INSERT_VALUES,SCATTER_FORWARD,ierr)

  ! end
  call VecScatterEnd(
 a_ts%from_petsc(0),a_XX,xxvec(0),INSERT_VALUES,SCATTER_FORWARD,ierr)
  a_n1 = n1
  call VecDestroy(xxvec(0),ierr)

  call VecScatterEnd(
 a_ts%from_petsc(1),a_XX,xxvec(1),INSERT_VALUES,SCATTER_FORWARD,ierr)
  a_apar = apar
  call VecDestroy(xxvec(1),ierr)

  call VecScatterEnd(
 a_ts%from_petsc(2),a_XX,xxvec(2),INSERT_VALUES,SCATTER_FORWARD,ierr)
  a_phi = phi
  call VecDestroy(xxvec(2),ierr)

  return
end subroutine scatter_to_xgc
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