[petsc-dev] asm / gasm

[Mark Adams]

GASM does assume the index set includes every equation in the matrix.  It
should probably check this as it has pmat.

I guess I can add these BC vertices in.

On Sun, Jun 26, 2016 at 11:20 AM, Mark Adams <mfadams at lbl.gov> wrote:

> Fande,
>
> An alternative debug path that may be simpler and direct, as it works with
> master:  'make runex56' in ksp/examples/tutorials in
> branch mark/gamg-agg-asm.
>
> This runs clean in valgrind (for me), I've added an ISView call to see the
> data that causes the error, it runs on one processor, uses a 3^3 cell grid
> (tiny), it exits cleanly with the error:
>
>  ....
> 87 189
> 88 190
> 89 191
> > [0]PETSC ERROR: --------------------- Error Message
> --------------------------------------------------------------
> > [0]PETSC ERROR: Argument out of range
> > [0]PETSC ERROR: Index 144 at 42 location greater than max 144
> [0]PETSC ERROR: #1 VecScatterCheckIndices_Private() line 39 in
> /Users/markadams/Codes/petsc/src/vec/vec/utils/vscat.c
> [0]PETSC ERROR: #2 VecScatterCreate() line 1227 in
> /Users/markadams/Codes/petsc/src/vec/vec/utils/vscat.c
> [0]PETSC ERROR: #3 PCSetUp_GASM() line 481 in
> /Users/markadams/Codes/petsc/src/ksp/pc/impls/gasm/gasm.c
>   ....
>
> This index 144 is very suspicious to me because there are 144 REAL dofs in
> this test, 192 "gross" dofs, minus (48) boundary conditions. This problem
> has just two aggregates with sizes 54 & 90 (=144). (I strip out the BC
> vertices.)
>
> Maybe GASM is getting confused because I do not give it domains that cover
> the entire mesh (I strip out BC vertices).  GASM thinks there are 144
> equations in this system when in fact there are 192.
>
> It looks to me like GASM is working a space stripped of BCs but it is
> using my indices that are in the full space.
>
> Mark
>
>
>
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