[petsc-users] -log_view hangs unexpectedly // how to optimize my kspsolve

[Manuel Valera]

Awesome Matt and Jed,

The GCR is used because the matrix is not invertible and because this was
the algorithm that the previous library used,

The Preconditioned im aiming to use is multigrid, i thought i configured
the hypre-boomerAmg solver for this, but i agree in that it doesn't show in
the log anywhere, how can i be sure is being used ? i sent -ksp_view log
before in this thread

I had a problem with the matrix block sizes so i couldn't make the petsc
native multigrid solver to work,

This is a nonhidrostatic pressure solver, it is an elliptic problem so
multigrid is a must,

Regards,

Manuel

On Sat, Jan 7, 2017 at 4:34 PM, Jed Brown <jed at jedbrown.org> wrote:

> Manuel Valera <mvalera at mail.sdsu.edu> writes:
>
> > I was able to find the bug, it was the outer loop bound in the same
> fashion
> > than before, my -log_view is this :
> [...]
> >       ##########################################################
> >       #                                                        #
> >       #                          WARNING!!!                    #
> >       #                                                        #
> >       #   This code was compiled with a debugging option,      #
> >       #   To get timing results run ./configure                #
> >       #   using --with-debugging=no, the performance will      #
> >       #   be generally two or three times faster.              #
> >       #                                                        #
> >       ##########################################################
>
> The above isn't a joke.
>
> > VecMDot              525 1.0 1.7089e+00 1.7 1.48e+09 1.0 0.0e+00 0.0e+00
> > 1.0e+03  7 17  0  0  6   7 17  0  0  6  1735
> >
> > VecMAXPY            1050 1.0 2.3646e+00 1.1 2.97e+09 1.0 0.0e+00 0.0e+00
> > 0.0e+00 11 34  0  0  0  11 34  0  0  0  2508
>
> You are spending about a third of the solve time doing vector work.
> What is your reason for using GCR?
>
> > KSPSolve               5 1.0 1.2218e+01 1.0 8.66e+09 1.0 1.1e+03 2.0e+04
> > 1.9e+04 59100 99 43 99  59100 99 43 99  1418
> >
> > PCSetUp                3 1.0 1.7993e+00 1.0 1.27e+07 1.0 0.0e+00 0.0e+00
> > 1.0e+01  8  0  0  0  0   8  0  0  0  0    14
> >
> > PCSetUpOnBlocks        5 1.0 1.9013e-01 1.7 1.27e+07 1.0 0.0e+00 0.0e+00
> > 0.0e+00  1  0  0  0  0   1  0  0  0  0   134
> >
> > PCApply              546 1.0 3.8320e+00 1.1 1.77e+09 1.0 0.0e+00 0.0e+00
> > 1.0e+00 18 20  0  0  0  18 20  0  0  0   925
>
> To make a big improvement, you'll need a better preconditioner.  What
> kind of problem is this?
>
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