On Thu, Mar 22, 2018 at 11:45 AM, Saurabh Chawdhary <[email protected]> wrote:
> Thank you Tobin. I was actually more interested in repartitioning after > the mesh has been dynamically changed (say, after refinement in certain > portions of mesh). > That kinds of repartitioning in p4est is handled by just splitting the Morton order into equal pieces, not by a graph partitioner. Matt > On 03/22/2018 07:10 AM, Tobin Isaac wrote: > >> >> On March 21, 2018 11:26:35 AM MDT, Saurabh Chawdhary <[email protected]> >> wrote: >> >>> Hello team, >>> >>> I haven't used petsc since DMFOREST was released but I have a question >>> regarding repartitioning of DMFOREST mesh. How is the repartitioning of >>> >>> mesh over processors done after some mesh refinement is carried out? Is >>> >>> it done by calling a p4est function or partitioning is done in PETSc? >>> >>> I was using p4est (natively) a couple of years ago and I remember that >>> when I tried to partition the grid I could only use the serial METIS >>> and >>> not the parMETIS with p4est (using a native function >>> /p4est_connectivity_reorder/). So what I want to know is whether >>> DMFOREST repartitioning is done in parallel or in serial? >>> >> You can use the following workflow: >> >> - Create/read-only an unstructured hexahedral mesh as a DMPlex >> - Use ParMETIS to repartition that: there is a ParMETIS implementation of >> PetscPartitioner, which creates index sets and communication patterns for >> DMPlexDistribute. >> - Convert the DMPlex to DMP4est or DMP8est. >> >> This does not avoid the fundamental limitations of p4est: the distributed >> mesh will be redundantly serialized behind-the-scenes, and the coarse-mesh >> ordering derived from ParMETIS will be static for the life of the forest >> mesh. >> > I am not sure I understand how the distributed mesh is redundantly > serialized in p4est. Do you mean that the partitioning is done serially? > >> >> >>> Thank you. >>> >>> Saurabh >>> >> > -- 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 https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
