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> >>>> 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 >>>>> >>>>> >>>> >>>> >>>> >>>> >>> >>> >> >> >> > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120510/8b4dfb2b/attachment.htm>
