[petsc-users] Reordering rows of parallel matrix across processors

[Cyrill Vonplanta]

Dear all,

I would like to reorder the rows of a matrix across processors. Is this possible with MatPermute(…)?

To illustrate here is how an index set would look like for a matrix with  M=35 on 2 CPU’s. Amongst other things I intend to swap the first and last row here.

[0] Number of indices in set 24
[0] 0 34
[0] 1 1
[0] 2 2
[0] 3 3
[0] 4 4
[0] 5 5
[0] 6 6
[0] 7 7
[0] 8 15
[0] 9 16
[0] 10 11
[0] 11 8
[0] 12 10
[0] 13 21
[0] 14 9
[0] 15 12
[0] 16 13
[0] 17 14
[0] 18 17
[0] 19 18
[0] 20 19
[0] 21 20
[0] 22 22
[0] 23 23
[1] Number of indices in set 11
[1] 0 24
[1] 1 25
[1] 2 26
[1] 3 27
[1] 4 28
[1] 5 29
[1] 6 30
[1] 7 31
[1] 8 32
[1] 9 33
[1] 10 0

Instead of exchanging the first and last row it seems to replace them with zeros only.
If this can’t be done with MatPermute how could it be done?

Thanks
Cyrill