[petsc-users] Numbering in MatView

[Barry Smith]

  If the matrix came from a DMDA then it is displayed in the "natural" ordering. Otherwise it is displayed in whatever parallel ordering it is using.

   Barry

> On Sep 29, 2015, at 1:27 AM, TAY wee-beng <zonexo at gmail.com> wrote:
> 
> Hi,
> 
> When I use MatView to output to an ASCII file, it gives:
> 
> Mat Object: 2 MPI processes
>  type: mpiaij
> row 0: (0, 1)  (1, 0)  (2, 0)  (3, 0)  (4, 0)  (5, 0)  (6, 0)  (7, 0)  (8, 0)  (12, -1)  (13, 0)  (14, 0)  (24, 0)  (25, 0)  (26, 0) (96, 0)  (97, 0)  (98, 0)  (192, 0)  (193, 0)  (194, 0)
> row 1: (0, 0)  (1, 13.4413)  (2, 0)  (3, 0)  (4, -0.00187601)  (5, 0)  (6, 0)  (7, 0)  (8, 0)  (12, 0)  (13, -0.000154087)  (14, 0) (24, 0)  (25, 0)  (26, 0)  (96, 0)  (97, -1.81928e-05)  (98, 0) (192, 0)  (193, 0)  (194, 0)
> row 2: (0, 0)  (1, 0)  (2, 1)  (3, 0)  (4, 0...
> 
> So how is the row numbered?
> 
> Does it uses the natural ordering or the PETSc ordering?
> 
> It seems to be the natural ordering since it doesn't change when I use 1,2 or 4 cpus, is that so?
> 
> -- 
> Thank you
> 
> Yours sincerely,
> 
> TAY wee-beng
>