On Thu, Aug 9, 2012 at 7:41 AM, Colin McAuliffe <cjm2176 at columbia.edu>wrote:
> From what I can gather from the petsc-dev source it looks like the > commands in 4) will then generate the splits using strided blocks. The > problem with that is No. I never use strided blocks. Matt > the fortran code I am using (FEAP) uses petsc to assemble and solve the > linear problem within its own nonlinear and time stepping schemes. The > linear problem that petsc solves already has boundary conditions applied to > it so petsc only sees the active (unrestrained) equations. So then in > general fields can't be extracted from the active equations using strided > blocks and I am stuck with generating the index sets defining the splits on > my own. Will it still be possible to make use of the new DM functions in > this case? > FEAP website: > http://www.ce.berkeley.edu/**projects/feap/<http://www.ce.berkeley.edu/projects/feap/> > > Colin > > > Quoting Matthew Knepley <knepley at gmail.com>: > > On Wed, Aug 8, 2012 at 10:51 PM, Matthew Knepley <knepley at gmail.com> >> wrote: >> >> On Wed, Aug 8, 2012 at 10:23 PM, Colin McAuliffe <cjm2176 at columbia.edu >>> >wrote: >>> >>> Thanks all, regarding use of DM in 3.3, is the procedure now to create >>>> the fields with PCFieldSplitSetIS and then use >>>> DMCreateFieldDecompositionDM >>>> to create a new DM based from the new fields and the DM for the original >>>> problem? >>>> >>>> >>> 1) Use petsc-dev >>> >>> 2) PCFieldSplitSetIS() is independent. This allows you to define splits >>> however you want, but then recursive gets harder >>> >>> 3) In 3.3., it uses DMCreateFieldDecompositionDM() to split all fields >>> apart at once >>> >>> 4) In petsc-dev, it uses DMCreateSubDM() which can split off any >>> combination of fields, which from the command line is something like >>> >>> -pc_fieldsplit_0_fields 2,0 -pc_fieldsplit_1_fields 1,3 >>> >>> >> I should have shown recursive: >> >> -fieldsplit_0_pc_type fieldsplit >> >> will split 2,0 into two blocks. >> >> Matt >> >> >> Matt >>> >>> >>> Colin >>>> >>>> -- >>>> Colin McAuliffe >>>> PhD Candidate >>>> Columbia University >>>> Department of Civil Engineering and Engineering Mechanics >>>> >>>> >>> >>> >>> -- >>> What most experimenters take for granted before they begin their >>> experiments is infinitely more interesting than any results to which >>> their >>> experiments lead. >>> -- Norbert Wiener >>> >>> >> >> >> -- >> What most experimenters take for granted before they begin their >> experiments is infinitely more interesting than any results to which their >> experiments lead. >> -- Norbert Wiener >> >> > > > -- > Colin McAuliffe > PhD Candidate > Columbia University > Department of Civil Engineering and Engineering Mechanics > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120809/27b470c2/attachment-0001.html>
