Dmitry,
I got the newest petsc-dev and I run the test by
mpirun -np 1 ./gasm_test -dd_type gasm -n 64 -dd_ksp_view
which gives the following output
PC Object:(dd_) 1 MPI processes
type: asm
Additive Schwarz: total subdomain blocks = 1, amount of overlap = 1
^^^
note the above number, it should be 2
While PCASM has no such problem.
Thanks,
Hui
> Hui,
>
> The convergence issue should be resolved in the latest petsc-dev.
> I'm attaching a slightly modified gasm_test.c (reflecting some upcoming API
> changes)
> that should verify that.
>
> Let me know if it works for you.
> Thanks.
> Dmitry.
> On Fri, May 11, 2012 at 12:31 PM, Hui Zhang <mike.hui.zhang at hotmail.com>
> wrote:
> Hi Dmitry,
>
> thanks for useful hints. Good day!
>
> Hui
>
> On May 11, 2012, at 7:17 PM, Dmitry Karpeev wrote:
>
>> You can call PCSetUp(pc) on either ASM or GASM, and that will destroy and
>> recreate the matrices (including calling
>> your modification subroutine), but not the subdomains or the subdomain
>> solvers.
>> If you just want to modify the submatrices, you can call
>> PC(G)ASMGetSubmatrices() and modify the matrices it returns
>> (in the same order as the subdomains were set). That's a bit of a hack,
>> since you will essentially be modifying the PC's internal data structures.
>> As long as you are careful, you should be okay, since you already
>> effectively have the same type of access to the submatrices through the
>> Modify callback.
>>
>> Dmitry.
>>
>> On Fri, May 11, 2012 at 11:52 AM, Hui Zhang <mike.hui.zhang at hotmail.com>
>> wrote:
>> I just have a question about reuse of PCASM or PCGASM.
>> Suppose I have seted up the PCASM and related KSP and I solved one time.
>> Next for the same linear system (matrix and RHS), I just want PCASM modify
>> the submatrices (PCSetModifySubmatrices) in a different way, using the same
>> routine for modifying but with
>> different user context for the modifying routine.
>>
>> What can I do for this task? Currently, I destroy the KSP and re-construct
>> it. I guess
>> even for PCASM I can re-use it because the partition of subdomains remain
>> the same.
>>
>> Thanks!
>>
>>
>> On May 10, 2012, at 6:37 PM, Dmitry Karpeev wrote:
>>
>>> Hui,
>>> There've been several changes to PCGASM ahead of the new release.
>>> Let me go back and see if it affected the convergence problem.
>>> Dmitry.
>>>
>>> On Thu, May 10, 2012 at 4:16 AM, Hui Zhang <mike.hui.zhang at hotmail.com>
>>> wrote:
>>> Hi Dmitry,
>>>
>>> is there any news about PCGASM?
>>>
>>> thanks,
>>> Hui
>>>
>>> On Feb 20, 2012, at 6:38 PM, Dmitry Karpeev wrote:
>>>
>>>> Okay, thanks.
>>>> I'll take a look.
>>>>
>>>> Dmitry.
>>>>
>>>> On Mon, Feb 20, 2012 at 11:30 AM, Hui Zhang <mike.hui.zhang at
>>>> hotmail.com> wrote:
>>>> For reference, my results are attached.
>>>>
>>>> asm1.txt for asm with 1 process,
>>>> asm2.txt for asm with 2 processes,
>>>> gasm1.txt for gasm with 1 process, (with the iteration numbers different
>>>> from others)
>>>> gasm2.txt for gasm with 2 processes
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> thank you,
>>>> Hui
>>>>
>>>> On Feb 20, 2012, at 3:06 PM, Dmitry Karpeev wrote:
>>>>
>>>>>
>>>>>
>>>>> On Mon, Feb 20, 2012 at 12:59 AM, Hui Zhang <mike.hui.zhang at
>>>>> hotmail.com> wrote:
>>>>>
>>>>> On Feb 20, 2012, at 12:41 AM, Dmitry Karpeev wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> On Sun, Feb 19, 2012 at 3:08 PM, Hui Zhang <mike.hui.zhang at
>>>>>> hotmail.com> wrote:
>>>>>> I have a new problem: the results from ASM and GASM are different and it
>>>>>> seems
>>>>>> GASM has something wrong with SetModifySubMatrices. Numerical tests are
>>>>>> with
>>>>>> each subdomain supported only by one subdomain. There are no problems
>>>>>> when
>>>>>> I did not modify submatrices. But when I modify submatrices, there are
>>>>>> problems
>>>>>> with GASM but no problems with ASM.
>>>>>>
>>>>>> For example, I use two subdomains. In the first case each subdomain is
>>>>>> supported by
>>>>>> one processor and there seems no problem with GASM. But when I use run
>>>>>> my program
>>>>>> with only one proc. so that it supports both of the two subdomains, the
>>>>>> iteration
>>>>>> number is different from the first case and is much larger. On the
>>>>>> other hand
>>>>>> ASM has no such problem.
>>>>>>
>>>>>> Are the solutions the same?
>>>>>> What problem are you solving?
>>>>>
>>>>> Yes, the solutions are the same. That's why ASM gives the same results
>>>>> with one or
>>>>> two processors. But GASM did not.
>>>>> Sorry, I wasn't clear: ASM and GASM produced different solutions in the
>>>>> case of two domains per processor?
>>>>> I'm solving the Helmholtz equation. Maybe
>>>>> I can prepare a simpler example to show this difference.
>>>>> That would be helpful.
>>>>> Thanks.
>>>>>
>>>>> Dmitry.
>>>>>
>>>>>>
>>>>>> Dmitry.
>>>>>>
>>>>>>
>>>>>> On Feb 15, 2012, at 6:46 PM, Dmitry Karpeev wrote:
>>>>>>
>>>>>>> You should be able to.
>>>>>>> This behavior is the same as in PCASM,
>>>>>>> except in GASM the matrices live on subcommunicators.
>>>>>>> I am in transit right now, but I can take a closer look in Friday.
>>>>>>>
>>>>>>> Dmitry
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Feb 15, 2012, at 8:07, Hui Zhang <mike.hui.zhang at hotmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> On Feb 15, 2012, at 11:19 AM, Hui Zhang wrote:
>>>>>>>>
>>>>>>>>> Hi Dmitry,
>>>>>>>>>
>>>>>>>>> thanks a lot! Currently, I'm not using ISColoring. Just comes another
>>>>>>>>> question
>>>>>>>>> on PCGASMSetModifySubMatrices(). The user provided function has the
>>>>>>>>> prototype
>>>>>>>>>
>>>>>>>>> func (PC pc,PetscInt nsub,IS *row,IS *col,Mat *submat,void *ctx);
>>>>>>>>>
>>>>>>>>> I think the coloumns from the parameter 'col' are always the same as
>>>>>>>>> the rows
>>>>>>>>> from the parameter 'row'. Because PCGASMSetLocalSubdomains() only
>>>>>>>>> accepts
>>>>>>>>> index sets but not rows and columns. Has I misunderstood something?
>>>>>>>>
>>>>>>>> As I tested, the row and col are always the same.
>>>>>>>>
>>>>>>>> I have a new question. Am I allowed to SetLocalToGlobalMapping() for
>>>>>>>> the submat's
>>>>>>>> in the above func()?
>>>>>>>>
>>>>>>>> thanks,
>>>>>>>> Hui
>>>>>>>>
>>>>>>>>>
>>>>>>>>> thanks,
>>>>>>>>> Hui
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Feb 11, 2012, at 3:36 PM, Dmitry Karpeev wrote:
>>>>>>>>>
>>>>>>>>>> Yes, that's right.
>>>>>>>>>> There is no good way to help the user assemble the subdomains at the
>>>>>>>>>> moment beyond the 2D stuff.
>>>>>>>>>> It is expected that they are generated from mesh subdomains.
>>>>>>>>>> Each IS does carry the subdomains subcomm.
>>>>>>>>>>
>>>>>>>>>> There is ISColoringToList() that is supposed to convert a "coloring"
>>>>>>>>>> of indices to an array of ISs,
>>>>>>>>>> each having the indices with the same color and the subcomm that
>>>>>>>>>> supports that color. It is
>>>>>>>>>> largely untested, though. You could try using it and give us
>>>>>>>>>> feedback on any problems you encounter.
>>>>>>>>>>
>>>>>>>>>> Dmitry.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Sat, Feb 11, 2012 at 6:06 AM, Hui Zhang <mike.hui.zhang at
>>>>>>>>>> hotmail.com> wrote:
>>>>>>>>>> About PCGASMSetLocalSubdomains(), in the case of one subdomain
>>>>>>>>>> supported by
>>>>>>>>>> multiple processors, shall I always create the arguments 'is[s]' and
>>>>>>>>>> 'is_local[s]'
>>>>>>>>>> in a subcommunicator consisting of processors supporting the
>>>>>>>>>> subdomain 's'?
>>>>>>>>>>
>>>>>>>>>> The source code of PCGASMCreateSubdomains2D() seemingly does so.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Hui
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>
> <gasm_test.c>
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