[petsc-users] Could DMComposite handle two vectors with different grid sizes.

[(Rebecca) Xuefei YUAN]

Dear Barry,

Thanks a lot for your reply.

Cheers,

Rebecca



Quoting Barry Smith <bsmith at mcs.anl.gov>:

>
>
>    What you are doing below looks ok. This builds the DM and DMMG.    
> See tutorials/multiphysics/mp1.c for an example that uses SNES to   
> solve a nonlinear equation on the grids.
>
>    Barry
>
>
>
> On Jul 27, 2010, at 7:36 PM, (Rebecca) Xuefei YUAN wrote:
>
>> Dear all,
>>
>> If I have two different vectors (with different dof, stencil width   
>> and grid sizes), could I use DMComposite to handle this?
>>
>> The following is the piece of code for assemble this DMComposite in DMMG.
>>
>> 	tempparameters.mxfield				= 5;
>> 	tempparameters.myfield				= 5;
>>
>> 	tempparameters.mxgrid	= tempparameters.mxfield+1;
>> 	tempparameters.mygrid	= tempparameters.myfield+1;
>>
>> 	ierr	= DMMGCreate(comm, tempparameters.numberOfLevels, &appCtx,   
>> &dmmg);CHKERRQ(ierr);
>>
>> 	ierr	= DMCompositeCreate(comm,&packer);CHKERRQ(ierr);
>>
>> 	ierr	= DACreate2d(comm,DA_NONPERIODIC,DA_STENCIL_BOX,   
>> tempparameters.mxfield, tempparameters.myfield, PETSC_DECIDE,   
>> PETSC_DECIDE, 4, 3, PETSC_NULL, PETSC_NULL, &da_fff);CHKERRQ(ierr);
>> 	ierr	= DASetFieldName(da_fff, 0, "phi");CHKERRQ(ierr);
>> 	ierr	= DASetFieldName(da_fff, 1, "vz");CHKERRQ(ierr);
>> 	ierr	= DASetFieldName(da_fff, 2, "psi");CHKERRQ(ierr);
>> 	ierr	= DASetFieldName(da_fff, 3, "bz");CHKERRQ(ierr);
>> 	ierr	= DACreate2d(comm,DA_NONPERIODIC,DA_STENCIL_BOX,   
>> tempparameters.mxgrid, tempparameters.mygrid, PETSC_DECIDE,   
>> PETSC_DECIDE, 1, tempparameters.gridStencilWidth, PETSC_NULL,   
>> PETSC_NULL, &da_ggg);CHKERRQ(ierr);
>> 	ierr	= DASetFieldName(da_ggg, 0, "disp");CHKERRQ(ierr);
>>
>> 	ierr	= DMCompositeAddDM(packer,(DM)da_fff);CHKERRQ(ierr);
>> 	ierr	= DMCompositeAddDM(packer,(DM)da_ggg);CHKERRQ(ierr);
>> 	ierr	= DMCompositeAddArray(packer,0,1);CHKERRQ(ierr);
>>
>> 	ierr	= DMMGSetDM(dmmg, (DM)packer);CHKERRQ(ierr);
>>
>> 	ierr	= DADestroy(da_fff);CHKERRQ(ierr);
>> 	ierr	= DADestroy(da_ggg);CHKERRQ(ierr);
>>
>> .........................................................
>>
>> 	ierr	= DMCompositeDestroy(packer);CHKERRQ(ierr);
>> 	ierr	= DMMGDestroy(dmmg);CHKERRQ(ierr);
>>
>>
>> I understand that for numberOfLevels(nl)>1, the grid size   
>> difference is no longer 1, but 3(nl=2), 5(nl=3), could I use   
>> DMComposite to handle such a case successfully?
>>
>> I was not able to get examples for such a case, is there any?
>>
>> Thanks a lot!
>>
>>
>>
>> --
>> (Rebecca) Xuefei YUAN
>> Department of Applied Physics and Applied Mathematics
>> Columbia University
>> Tel:917-399-8032
>> www.columbia.edu/~xy2102
>>
>
>
>



-- 
(Rebecca) Xuefei YUAN
Department of Applied Physics and Applied Mathematics
Columbia University
Tel:917-399-8032
www.columbia.edu/~xy2102