Hi Hong,
Thank you that was unclear to me, now I understand its purpose!
Thibaut
On 08/10/2019 16:18, Zhang, Hong wrote:
Thibaut :
Sorry, I did not explain it clearly. You call
MatSetOption(A,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);
AFTER matrix is assembled. Then no more new zero is allowed to
add/insert. For example, I add following in
petsc/src/ksp/ksp/examples/tutorials/ex1.c:
ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
+ ierr =
MatSetOption(A,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
+ i = 0; col[0] = 2;
+ ierr = MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);CHKERRQ(ierr);
+ ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
+ ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
+
Then the code crashes with
0]PETSC ERROR: Argument out of range
[0]PETSC ERROR: Inserting a new nonzero at (0,2) in the matrix.
Adding entries to the tridiagonal works.
Hong
Well, try and create a small SEQAIJ/MPIAIJ matrix and preallocate
memory for the diagonal.
When I try to call MatSetValues to fill the diagonal, on the first
row I get
[0]PETSC ERROR: Argument out of range
[0]PETSC ERROR: Inserting a new nonzero at (0,0) in the matrix
Which is within my preallocated non-zero structure.
This is why I'm confused.
Thibaut
On 08/10/2019 15:31, Zhang, Hong wrote:
Thibaut:
Hi,
Just out of curiosity, I'm a bit confused by the parameter
option
MAT_NEW_NONZERO_LOCATION_ERR.
It triggers an error if you try to insert/add a value in the
non-zero
structure, regardless of the matrix preallocation status. In
what case
would such an option be useful?
It triggers an error if you try to insert/add a NEW value
outside of your preallocated non-zero structure.
Hong
