This looks like one block row per process? (BAIJ formats store explicit zeros
that appear within nonzero blocks.) You'd use d_nnz[] = {1}, o_nnz[] = {1} on
each process.
If each of the dummy numbers there was replaced by a nonzero block (so the
diagram would be sketching nonzero 3x3 blocks of
Thank you Jed for the hint.
So just to understand it with an example. Say I have this matrix here,
which has 4 3x3 blocks
1 2 0 | 0 5 0 |
0 2 3 | 0 0 1 | < Proc 1
0 0 1 | 0 2 2 |
||
1 2 0 | 0 5 0 |
0 2 0 | 0 0 1 | < Proc 2
0 0 1 | 0 0 2 |
---|-|
I recommend calling this one preallocation function, which will preallocate
scalar and block formats. It takes one value per block row, counting in blocks.
https://petsc.org/release/docs/manualpages/Mat/MatXAIJSetPreallocation/
Edoardo alinovi writes:
> Hello Barry,
>
> I am doing some
Hello Barry,
I am doing some preliminary work to add a coupled solver in my code. I am
reading some documentation on MPIBAIJ as the matrix will be composed of
blocks of size 3x3 in 2D and 4x4 in 3D for each cell in the domain.
I can't quite understand how to set d_nnz and o_nnz. What is their
