[petsc-users] Local and global size of IS

[Eda Oktay]

Hello,

I am trying to permute a matrix A(of size 2n*2n) according to a sorted
eigenvector vr (of size 2n) in parallel using 2 processors (processor
number can change). However, I get an error in MatPermute line stating that
arguments are out of range and a new nonzero caused a malloc even if I used
MatSetOption.

I discovered that this may be because of the unequality of local sizes of
is (and newIS) and local size of A.

Since I allocate index set idx according to size of the vector vr, global
size of is becomes 2n and the local size is also 2n (I think it should be n
since both A and vr has local sizes n because of the number of processors).
If I change the size of idx, then because of VecGetArrayRead, I think is is
created wrongly.

So, how can I make both global and local sizes of is,newIS and A?

Below, you can see the part of my program.

Thanks,

Eda

 ierr = VecGetSize(vr,&siz);CHKERRQ(ierr);
  ierr = PetscMalloc1(siz,&idx);CHKERRQ(ierr);
  for (i=0; i<siz;i++) idx[i] = i;
  ierr = VecGetArrayRead(vr,&avr);CHKERRQ(ierr);
  ierr = PetscSortRealWithPermutation(siz,avr,idx);CHKERRQ(ierr);

  ierr =
ISCreateGeneral(PETSC_COMM_SELF,siz,idx,PETSC_COPY_VALUES,&is);CHKERRQ(ierr);
  ierr = ISSetPermutation(is);CHKERRQ(ierr);
  ierr = ISDuplicate(is,&newIS);CHKERRQ(ierr);
MatSetOption(A,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr);
  ierr = MatPermute(A,is,newIS,&PL);CHKERRQ(ierr);
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