I'm a bit confused. Since the C KSPSolve() always resets the counter to zero
I don't understand why the Python call (which presumably calls the C version
doesn't get it reset). Or does the python version not call the C version.
I'm fine with either solution I guess but I'd like to understand why the C
behavior doesn't just automatically happen with the Python.
Barry
> On Mar 4, 2019, at 12:07 AM, Lisandro Dalcin <dalc...@gmail.com> wrote:
>
> I pushed the fix to branch dalcinl/fix-ksp-ex100
>
> On Mon, 4 Mar 2019 at 09:01, Lisandro Dalcin <dalc...@gmail.com> wrote:
> Well, this is just because the Python code implementing KSPSolve does not
> reset the iteration counter to zero. This was an oversight on my part when I
> wrote that code ages ago.
>
> Barry, I'm wondering whether this should be done at the interface rather than
> implementation level? If you do not want to change things in core KSP (and
> then maybe SNES, etc), the the following patch should fix things.
>
>
> diff --git a/src/ksp/ksp/examples/tutorials/example100.py
> b/src/ksp/ksp/examples/tutorials/example100.py
> index ef085522bf..7ad03ec194 100644
> --- a/src/ksp/ksp/examples/tutorials/example100.py
> +++ b/src/ksp/ksp/examples/tutorials/example100.py
> @@ -119,11 +119,13 @@ class ConjGrad(object):
>
> def solve(self, ksp, b, x):
> LOG('ConjGrad.solve()')
> + ksp.setIterationNumber(0)
> A, P = get_op_pc(ksp, transpose=False)
> pcg(ksp, A, P, b, x, *self.work)
>
> def solveTranspose(self, ksp, b, x):
> LOG('ConjGrad.solveTranspose()')
> + ksp.setIterationNumber(0)
> A, P = get_op_pc(ksp, transpose=True)
> pcg(ksp, A, P, b, x, *self.work)
>
>
> On Mon, 4 Mar 2019 at 06:15, Smith, Barry F. <bsm...@mcs.anl.gov> wrote:
>
> Pierre,
>
> I can confirm the problem.
>
> Lisandro,
>
> Could you please take a look at this? I have no explanation for why this
> would happen.
>
> Barry
>
>
>
> > On Feb 25, 2019, at 1:21 PM, Pierre Jolivet via petsc-dev
> > <petsc-dev@mcs.anl.gov> wrote:
> >
> > I’m not sure this is the expected behavior. Is it?
> > $ git diff ex100.py
> > diff --git a/src/ksp/ksp/examples/tutorials/ex100.py
> > b/src/ksp/ksp/examples/tutorials/ex100.py
> > index dbb3f8e012..051637ce1d 100644
> > --- a/src/ksp/ksp/examples/tutorials/ex100.py
> > +++ b/src/ksp/ksp/examples/tutorials/ex100.py
> > @@ -29,6 +29,7 @@ def RunTest():
> > ksp.setOperators(A, A)
> > ksp.setFromOptions()
> > ksp.solve(b, x)
> > + ksp.solve(b, x)
> >
> > r = b.duplicate()
> > A.mult(x, r)
> >
> > $ mpirun -np 8 python ./ex100.py -ksp_converged_reason -ksp_monitor
> > 0 KSP Residual norm 5.101520253035e-04
> > 1 KSP Residual norm 1.168905135944e-03
> > [..]
> > 12 KSP Residual norm 5.101520253035e-05
> > 13 KSP Residual norm 7.504522604366e-20
> > Linear solve converged due to CONVERGED_RTOL iterations 13
> > 13 KSP Residual norm 5.101520253035e-04
> > 14 KSP Residual norm 1.168905135944e-03
> > [..]
> > 25 KSP Residual norm 5.101520253035e-05
> > 26 KSP Residual norm 7.504522604366e-20
> > Linear solve converged due to CONVERGED_RTOL iterations 26
> >
> > Shouldn’t the iterate number be reset to 0 for the 2nd KSPSolve?
> >
> > Thanks,
> > Pierre
>
>
>
> --
> Lisandro Dalcin
> ============
> Research Scientist
> Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
> Extreme Computing Research Center (ECRC)
> King Abdullah University of Science and Technology (KAUST)
> http://ecrc.kaust.edu.sa/
>
> 4700 King Abdullah University of Science and Technology
> al-Khawarizmi Bldg (Bldg 1), Office # 0109
> Thuwal 23955-6900, Kingdom of Saudi Arabia
> http://www.kaust.edu.sa
>
> Office Phone: +966 12 808-0459
>
>
> --
> Lisandro Dalcin
> ============
> Research Scientist
> Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
> Extreme Computing Research Center (ECRC)
> King Abdullah University of Science and Technology (KAUST)
> http://ecrc.kaust.edu.sa/
>
> 4700 King Abdullah University of Science and Technology
> al-Khawarizmi Bldg (Bldg 1), Office # 0109
> Thuwal 23955-6900, Kingdom of Saudi Arabia
> http://www.kaust.edu.sa
>
> Office Phone: +966 12 808-0459
