On Jan 6, 2012, at 4:43 PM, Xuefeng Li wrote: > On Fri, 6 Jan 2012, Matthew Knepley wrote: > >> On Fri, Jan 6, 2012 at 4:32 PM, Xuefeng Li <li at loyno.edu> wrote: >> >>> However, is there a way to change/adjust the stencil width >>> AFTER the DA has been created and set up to a DMMG? Or, >>> in general, can we attach different DA objects to a DMMG >>> at different times? >>> >> >> 1) You cannot change this after setting up the DA. Just make another DA, >> since >> they are very lightweight. >> >> 2) I think structuring new code around DMMG is wrong. It has been removed in >> petsc-dev and is deprecated in 3.2. What are you trying to do? >> > I am just trying to use the ghost points to share > data among neighboring processes at one step > during the whole iteration. At that particular > step, the stencil width needs to be bigger. > > One can always set the stencil width to be big > enough so that one does not need to adjust it. > But this is just not as efficient as it can be.
Just create a bigger-stencil DMDA that you use during those "special" steps. Barry > > Thanks again. > > Regards, > > --Xuefeng Li, (504)865-3340(phone) > Like floating clouds, the heart rests easy > Like flowing water, the spirit stays free > http://www.loyno.edu/~li/home > New Orleans, Louisiana (504)865-2051(fax) >
