On Sun, Sep 4, 2011 at 10:08 AM, ??????? ??????? <ram at ibrae.ac.ru> wrote:
> Hello! > Help me please to solve my tiny problem with dmmg. > > In the example src/ksp/ksp/examples/tutorials/ex22.c, which is discussed on > the 111th page of users manual, we use function > (line 36): > DACreate3d(PETSC_COMM_WORLD,DA_NONPERIODIC,DA_STENCIL_STAR,-3,-3,-3,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,1,1,0,0,0,&da); > to "*create the DA that stores information about the coarsest grid you > wish to use*". > We can see that negative dimension values (-M, -N, -P) are used "*to > indicate that it may be set to a different value from the command line with > -da_grid_x <M> -da_grid_y <N> -da_grid_z <P>". * > The question is: when I use -da_grid_ M,N,P options as the size of the > coarsest matrix, what's the size of the finest (most accurate, original > problem) matrix? > > I've tried to clear this up, using VecVew on the residual vector and > figured out, that when i'm using M,N,P as input parameters (so define the > coarsest grid as field of M*N*P dots), I get the residual vector of size > (4*M-3)*(4*N-3)*(4*P-3). > Is my result correct? If yes, could you please explain why it happens in > this way. > When refinement happens, it adds a vertex between any two vertices, starting with the mesh you provide. Matt > Sorry if my question is incorrect. I could mix up everything at all. > Thanks in advance! > > -- > Best regards, > Alexey Ryazanov > ______________________________________ > Nuclear Safety Institute of Russian Academy of Sciences > > > -- 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/20110904/5f0bace8/attachment-0001.htm>
