Re: [petsc-dev] do all MIS algorithms require a symmetric structure?

On Sun, Sep 18, 2022 at 7:04 PM Barry Smith wrote: > > Right, but I want to run with the old options MIS (instead of MIS-2) and > get the same times as before. But instead I am getting much larger times. > Yea, the new MIS is noticeably slower New: petsc/src/ksp/ksp/tutorials$ mpiexec -n 4

Re: [petsc-dev] do all MIS algorithms require a symmetric structure?

Right, but I want to run with the old options MIS (instead of MIS-2) and get the same times as before. But instead I am getting much larger times. > On Sep 18, 2022, at 6:58 PM, Mark Adams wrote: > > > > On Sun, Sep 18, 2022 at 6:19 PM Barry Smith > wrote: > >

Re: [petsc-dev] do all MIS algorithms require a symmetric structure?

On Sun, Sep 18, 2022 at 6:19 PM Barry Smith wrote: > > Mark, > > Some how your changes to GAMG in June slowed down the time to compute > the MIS dramatically. I cannot figure out what options to use to > get the exact same performance as an older branch. -mat_coarsen_type mis >

Re: [petsc-dev] do all MIS algorithms require a symmetric structure?

On Sun, Sep 18, 2022 at 5:11 PM Barry Smith wrote: > >Does the MIS you use, use the numerical values in the matrix? Looking > at the code it looks like not, while hem does seems to use them. > Yes. numerical values are used in the filtering. > >But MatCreateGraph() seems to always get

Re: [petsc-dev] do all MIS algorithms require a symmetric structure?

Mark, Some how your changes to GAMG in June slowed down the time to compute the MIS dramatically. I cannot figure out what options to use to get the exact same performance as an older branch. -mat_coarsen_type mis -pc_gamg_threshold 0 result in longer times than the older code with its

Re: [petsc-dev] do all MIS algorithms require a symmetric structure?

Does the MIS you use, use the numerical values in the matrix? Looking at the code it looks like not, while hem does seems to use them. But MatCreateGraph() seems to always get the numerical values, makes them positive and then scales them by the diagonal even when no filtering will be

Re: [petsc-dev] do all MIS algorithms require a symmetric structure?

On Sun, Sep 18, 2022 at 4:02 PM Barry Smith wrote: > > Mark, > >Do all MIS algorithms in PETSc require a symmetric graph structure? > And parallel ones can hang if not structurally symmetric? > Yes, > >When used sequentially I guess it never hangs but it may not produce a >

[petsc-dev] do all MIS algorithms require a symmetric structure?

Mark, Do all MIS algorithms in PETSc require a symmetric graph structure? And parallel ones can hang if not structurally symmetric? When used sequentially I guess it never hangs but it may not produce a "correct" MIS if the matrix structure is not symmetric? But like the MIS is