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/20120220/d998a0fe/attachment.htm>
