Consider the following code:
ierr = ISSorted(iscol[i], &sorted); CHKERRQ(ierr);
if (!sorted) SETERRQ1(((PetscObject)iscol[i])->comm, PETSC_ERR_SUP, "Column
index set %D not sorted", i);
ISSorted() is not a collective operation and just determines if the local
part of the IS is sorted.
Hence some processes in comm may return true and some may return false.
In this situation you CANNOT call SETERRQ() with that collective comm. You
must call it with PETSC_COMM_SELF
You can ONLY CALL SETERRQ with a collective comm if you know with absolute
certainty that all processes in the comm will be calling it.
Barry
