On Wed, 16 Aug 2006, Thomas Geenen wrote: > dear petsc users, > > is there a way to prevent Petsc during the assembly phase from redistributing > matrix rows over cpu's ??
The row distribution is done at matrix creation time - and you can set the row distribution with MatSetSizes() [or MatCreateMPIAIJ() etc..] by using the correct distribution value - instead of PETSC_DECIDE > i like the way the rows are assigned to the cpu's during the > setvalues phase. I don't understand this statement. The row assignment doesn't change > apparently petsc assigns the first nrows to cpu0 the second nrows to cpu1 etc. yes. this fact can't be changed. > I could of course renumber my matrix but I would rather convince > petsc that it should keep the distribution of the matrix rows. If you have some other global numbering scheme which is inconsitant with the matrix row numbering scheme - then you can use 'AO' object and associated routines to convert between mappings. Note: 'row distribution' is different from 'row numbering'. Satish
