[petsc-users] monitoring the convergence of fieldsplit 0 and 1
Matthew Knepley
knepley at gmail.com
Wed Jan 18 09:13:52 CST 2017
On Wed, Jan 18, 2017 at 4:42 AM, Klaij, Christiaan <C.Klaij at marin.nl> wrote:
> Thanks Lawrence, that nicely explains the unexpected behaviour!
>
> I guess in general there ought to be getters for the four
> ksp(A00)'s that occur in the full factorization.
Yes, we will fix it. I think that the default retrieval should get the 00
block, not the inner as well.
Matt
>
> Chris
>
>
> dr. ir. Christiaan Klaij | CFD Researcher | Research & Development
> MARIN | T +31 317 49 33 44 | mailto:C.Klaij at marin.nl | http://www.marin.nl
>
> MARIN news: http://www.marin.nl/web/News/News-items/Verification-and-
> validation-exercises-for-flow-around-KVLCC2-tanker.htm
>
> ________________________________________
> From: Lawrence Mitchell <lawrence.mitchell at imperial.ac.uk>
> Sent: Wednesday, January 18, 2017 10:59 AM
> To: petsc-users at mcs.anl.gov
> Cc: bsmith at mcs.anl.gov; Klaij, Christiaan
> Subject: Re: [petsc-users] monitoring the convergence of fieldsplit 0 and 1
>
> On 18/01/17 08:40, Klaij, Christiaan wrote:
> > Barry,
> >
> > I've managed to replicate the problem with 3.7.4
> > snes/examples/tutorials/ex70.c. Basically I've added
> > KSPGetTotalIterations to main (file is attached):
>
> PCFieldSplitGetSubKSP returns, in the Schur case:
>
> MatSchurComplementGet(pc->schur, &ksp);
>
> in subksp[0]
>
> and
>
> pc->schur in subksp[1]
>
> In your case, subksp[0] is the (preonly) approximation to A^{-1} *inside*
>
> S = D - C A_inner^{-1} B
>
> And subksp[1] is the approximation to S^{-1}.
>
> Since each application of S to a vector (required in S^{-1}) requires
> one application of A^{-1}, because you use 225 iterations in total to
> invert S, you also use 225 applications of the KSP on A_inner.
>
> There doesn't appear to be a way to get the KSP used for A^{-1} if
> you've asked for different approximations to A^{-1} in the 0,0 block
> and inside S.
>
> Cheers,
>
> Lawrence
>
> > $ diff -u ex70.c.bak ex70.c
> > --- ex70.c.bak2017-01-18 09:25:46.286174830 +0100
> > +++ ex70.c2017-01-18 09:03:40.904483434 +0100
> > @@ -669,6 +669,10 @@
> > KSP ksp;
> > PetscErrorCode ierr;
> >
> > + KSP *subksp;
> > + PC pc;
> > + PetscInt numsplit = 1, nusediter_vv, nusediter_pp;
> > +
> > ierr = PetscInitialize(&argc, &argv, NULL, help);CHKERRQ(ierr);
> > s.nx = 4;
> > s.ny = 6;
> > @@ -690,6 +694,13 @@
> > ierr = StokesSetupPC(&s, ksp);CHKERRQ(ierr);
> > ierr = KSPSolve(ksp, s.b, s.x);CHKERRQ(ierr);
> >
> > + ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
> > + ierr = PCFieldSplitGetSubKSP(pc,&numsplit,&subksp); CHKERRQ(ierr);
> > + ierr = KSPGetTotalIterations(subksp[0],&nusediter_vv); CHKERRQ(ierr);
> > + ierr = KSPGetTotalIterations(subksp[1],&nusediter_pp); CHKERRQ(ierr);
> > + ierr = PetscPrintf(PETSC_COMM_WORLD," total u solves = %i\n",
> nusediter_vv); CHKERRQ(ierr);
> > + ierr = PetscPrintf(PETSC_COMM_WORLD," total p solves = %i\n",
> nusediter_pp); CHKERRQ(ierr);
> > +
> > /* don't trust, verify! */
> > ierr = StokesCalcResidual(&s);CHKERRQ(ierr);
> > ierr = StokesCalcError(&s);CHKERRQ(ierr);
> >
> > Now run as follows:
> >
> > $ mpirun -n 2 ./ex70 -ksp_type fgmres -pc_type fieldsplit
> -pc_fieldsplit_type schur -pc_fieldsplit_schur_fact_type lower
> -fieldsplit_0_ksp_type gmres -fieldsplit_0_pc_type bjacobi
> -fieldsplit_1_pc_type jacobi -fieldsplit_1_inner_ksp_type preonly
> -fieldsplit_1_inner_pc_type jacobi -fieldsplit_1_upper_ksp_type preonly
> -fieldsplit_1_upper_pc_type jacobi -fieldsplit_0_ksp_converged_reason
> -fieldsplit_1_ksp_converged_reason
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 14
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 14
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 16
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 16
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 17
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 18
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 20
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 21
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 23
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 22
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 22
> > Linear fieldsplit_0_ solve converged due to CONVERGED_RTOL iterations 5
> > Linear fieldsplit_1_ solve converged due to CONVERGED_RTOL iterations
> 22
> > total u solves = 225
> > total p solves = 225
> > residual u = 9.67257e-06
> > residual p = 5.42082e-07
> > residual [u,p] = 9.68775e-06
> > discretization error u = 0.0106464
> > discretization error p = 1.85907
> > discretization error [u,p] = 1.8591
> >
> > So here again the total of 225 is correct for p, but for u it
> > should be 60. Hope this helps you find the problem.
> >
> > Chris
> >
> >
> >
> > dr. ir. Christiaan Klaij | CFD Researcher | Research & Development
> > MARIN | T +31 317 49 33 44 | mailto:C.Klaij at marin.nl |
> http://www.marin.nl
> >
> > MARIN news: http://www.marin.nl/web/News/News-items/Few-places-left-
> for-Offshore-and-Ship-hydrodynamics-courses.htm
> >
> > ________________________________________
> > From: Klaij, Christiaan
> > Sent: Tuesday, January 17, 2017 8:45 AM
> > To: Barry Smith
> > Cc: petsc-users at mcs.anl.gov
> > Subject: Re: [petsc-users] monitoring the convergence of fieldsplit 0
> and 1
> >
> > Well, that's it, all the rest was hard coded. Here's the relevant part
> of the code:
> >
> > CALL PCSetType(pc_system,PCFIELDSPLIT,ierr); CHKERRQ(ierr)
> > CALL PCFieldSplitSetType(pc_system,PC_COMPOSITE_SCHUR,ierr);
> CHKERRQ(ierr)
> > CALL PCFieldSplitSetIS(pc_system,"0",isgs(1),ierr); CHKERRQ(ierr)
> > CALL PCFieldSplitSetIS(pc_system,"1",isgs(2),ierr); CHKERRQ(ierr)
> > CALL PCFieldSplitSetSchurFactType(pc_system,PC_FIELDSPLIT_SCHUR_
> FACT_FULL,ierr);CHKERRQ(ierr)
> > CALL PCFieldSplitSetSchurPre(pc_system,PC_FIELDSPLIT_SCHUR_
> PRE_SELFP,PETSC_NULL_OBJECT,ierr);CHKERRQ(ierr)
> >
> > CALL KSPSetTolerances(ksp_system,tol,PETSC_DEFAULT_REAL,PETSC_DEFAULT_REAL,maxiter,ierr);
> CHKERRQ(ierr)
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_0_ksp_rtol","0.01",ierr);
> CHKERRQ(ierr)
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_1_ksp_rtol","0.01",ierr);
> CHKERRQ(ierr)
> >
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_0_ksp_pc_side","right",ierr);
> CHKERRQ(ierr)
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_1_ksp_pc_side","right",ierr);
> CHKERRQ(ierr)
> >
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_0_ksp_type","gmres",ierr);
> CHKERRQ(ierr)
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_
> 1_upper_ksp_type","preonly",ierr); CHKERRQ(ierr)
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_
> 1_upper_pc_type","jacobi",ierr); CHKERRQ(ierr)
> >
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_
> 1_inner_ksp_type","preonly",ierr); CHKERRQ(ierr)
> > CALL PetscOptionsSetValue(PETSC_NULL_OBJECT,"-sys_fieldsplit_
> 1_inner_pc_type","jacobi",ierr); CHKERRQ(ierr)
> >
> > ________________________________________
> > From: Barry Smith <bsmith at mcs.anl.gov>
> > Sent: Monday, January 16, 2017 9:28 PM
> > To: Klaij, Christiaan
> > Cc: petsc-users at mcs.anl.gov
> > Subject: Re: [petsc-users] monitoring the convergence of fieldsplit 0
> and 1
> >
> > Please send all the command line options you use.
> >
> >
> >> On Jan 16, 2017, at 1:47 AM, Klaij, Christiaan <C.Klaij at marin.nl>
> wrote:
> >>
> >> Barry,
> >>
> >> Sure, here's the output with:
> >>
> >> -sys_ksp_view -sys_ksp_converged_reason -sys_fieldsplit_0_ksp_converged_reason
> -sys_fieldsplit_1_ksp_converged_reason
> >>
> >> (In my previous email, I rearranged 0 & 1 for easy summing.)
> >>
> >> Chris
> >>
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 1
> >> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 22
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 1
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 2
> >> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 6
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 2
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 3
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 2
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 2
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 2
> >> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >> Linear sys_ solve converged due to CONVERGED_RTOL iterations 6
> >> KSP Object:(sys_) 1 MPI processes
> >> type: fgmres
> >> GMRES: restart=30, using Classical (unmodified) Gram-Schmidt
> Orthogonalization with no iterative refinement
> >> GMRES: happy breakdown tolerance 1e-30
> >> maximum iterations=300, initial guess is zero
> >> tolerances: relative=0.01, absolute=1e-50, divergence=10000.
> >> right preconditioning
> >> using UNPRECONDITIONED norm type for convergence test
> >> PC Object:(sys_) 1 MPI processes
> >> type: fieldsplit
> >> FieldSplit with Schur preconditioner, factorization FULL
> >> Preconditioner for the Schur complement formed from Sp, an assembled
> approximation to S, which uses (lumped, if requested) A00's diagonal's
> inverse
> >> Split info:
> >> Split number 0 Defined by IS
> >> Split number 1 Defined by IS
> >> KSP solver for A00 block
> >> KSP Object: (sys_fieldsplit_0_) 1 MPI processes
> >> type: gmres
> >> GMRES: restart=30, using Classical (unmodified) Gram-Schmidt
> Orthogonalization with no iterative refinement
> >> GMRES: happy breakdown tolerance 1e-30
> >> maximum iterations=10000, initial guess is zero
> >> tolerances: relative=0.01, absolute=1e-50, divergence=10000.
> >> right preconditioning
> >> using UNPRECONDITIONED norm type for convergence test
> >> PC Object: (sys_fieldsplit_0_) 1 MPI processes
> >> type: ilu
> >> ILU: out-of-place factorization
> >> 0 levels of fill
> >> tolerance for zero pivot 2.22045e-14
> >> matrix ordering: natural
> >> factor fill ratio given 1., needed 1.
> >> Factored matrix follows:
> >> Mat Object: 1 MPI processes
> >> type: seqaij
> >> rows=9600, cols=9600
> >> package used to perform factorization: petsc
> >> total: nonzeros=47280, allocated nonzeros=47280
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> linear system matrix = precond matrix:
> >> Mat Object: (sys_fieldsplit_0_) 1 MPI processes
> >> type: seqaij
> >> rows=9600, cols=9600
> >> total: nonzeros=47280, allocated nonzeros=47280
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> KSP solver for upper A00 in upper triangular factor
> >> KSP Object: (sys_fieldsplit_1_upper_) 1 MPI processes
> >> type: preonly
> >> maximum iterations=10000, initial guess is zero
> >> tolerances: relative=1e-05, absolute=1e-50, divergence=10000.
> >> left preconditioning
> >> using NONE norm type for convergence test
> >> PC Object: (sys_fieldsplit_1_upper_) 1 MPI processes
> >> type: jacobi
> >> linear system matrix = precond matrix:
> >> Mat Object: (sys_fieldsplit_0_) 1 MPI processes
> >> type: seqaij
> >> rows=9600, cols=9600
> >> total: nonzeros=47280, allocated nonzeros=47280
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> KSP solver for S = A11 - A10 inv(A00) A01
> >> KSP Object: (sys_fieldsplit_1_) 1 MPI processes
> >> type: gmres
> >> GMRES: restart=30, using Classical (unmodified) Gram-Schmidt
> Orthogonalization with no iterative refinement
> >> GMRES: happy breakdown tolerance 1e-30
> >> maximum iterations=10000, initial guess is zero
> >> tolerances: relative=0.01, absolute=1e-50, divergence=10000.
> >> right preconditioning
> >> using UNPRECONDITIONED norm type for convergence test
> >> PC Object: (sys_fieldsplit_1_) 1 MPI processes
> >> type: ilu
> >> ILU: out-of-place factorization
> >> 0 levels of fill
> >> tolerance for zero pivot 2.22045e-14
> >> matrix ordering: natural
> >> factor fill ratio given 1., needed 1.
> >> Factored matrix follows:
> >> Mat Object: 1 MPI processes
> >> type: seqaij
> >> rows=3200, cols=3200
> >> package used to perform factorization: petsc
> >> total: nonzeros=40404, allocated nonzeros=40404
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> linear system matrix followed by preconditioner matrix:
> >> Mat Object: (sys_fieldsplit_1_) 1 MPI processes
> >> type: schurcomplement
> >> rows=3200, cols=3200
> >> Schur complement A11 - A10 inv(A00) A01
> >> A11
> >> Mat Object: (sys_fieldsplit_1_)
> 1 MPI processes
> >> type: seqaij
> >> rows=3200, cols=3200
> >> total: nonzeros=40404, allocated nonzeros=40404
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> A10
> >> Mat Object: 1 MPI processes
> >> type: seqaij
> >> rows=3200, cols=9600
> >> total: nonzeros=47280, allocated nonzeros=47280
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> KSP of A00
> >> KSP Object: (sys_fieldsplit_1_inner_)
> 1 MPI processes
> >> type: preonly
> >> maximum iterations=10000, initial guess is zero
> >> tolerances: relative=1e-05, absolute=1e-50,
> divergence=10000.
> >> left preconditioning
> >> using NONE norm type for convergence test
> >> PC Object: (sys_fieldsplit_1_inner_)
> 1 MPI processes
> >> type: jacobi
> >> linear system matrix = precond matrix:
> >> Mat Object: (sys_fieldsplit_0_)
> 1 MPI processes
> >> type: seqaij
> >> rows=9600, cols=9600
> >> total: nonzeros=47280, allocated nonzeros=47280
> >> total number of mallocs used during MatSetValues calls
> =0
> >> not using I-node routines
> >> A01
> >> Mat Object: 1 MPI processes
> >> type: seqaij
> >> rows=9600, cols=3200
> >> total: nonzeros=47280, allocated nonzeros=47280
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> Mat Object: 1 MPI processes
> >> type: seqaij
> >> rows=3200, cols=3200
> >> total: nonzeros=40404, allocated nonzeros=40404
> >> total number of mallocs used during MatSetValues calls =0
> >> not using I-node routines
> >> linear system matrix followed by preconditioner matrix:
> >> Mat Object: 1 MPI processes
> >> type: nest
> >> rows=12800, cols=12800
> >> Matrix object:
> >> type=nest, rows=2, cols=2
> >> MatNest structure:
> >> (0,0) : prefix="mom_", type=seqaij, rows=9600, cols=9600
> >> (0,1) : prefix="grad_", type=seqaij, rows=9600, cols=3200
> >> (1,0) : prefix="div_", type=seqaij, rows=3200, cols=9600
> >> (1,1) : prefix="stab_", type=seqaij, rows=3200, cols=3200
> >> Mat Object: 1 MPI processes
> >> type: nest
> >> rows=12800, cols=12800
> >> Matrix object:
> >> type=nest, rows=2, cols=2
> >> MatNest structure:
> >> (0,0) : prefix="sys_fieldsplit_0_", type=seqaij, rows=9600,
> cols=9600
> >> (0,1) : type=seqaij, rows=9600, cols=3200
> >> (1,0) : type=seqaij, rows=3200, cols=9600
> >> (1,1) : prefix="sys_fieldsplit_1_", type=seqaij, rows=3200,
> cols=3200
> >> nusediter_vv 37
> >> nusediter_pp 37
> >>
> >>
> >>
> >> dr. ir. Christiaan Klaij | CFD Researcher | Research & Development
> >> MARIN | T +31 317 49 33 44 | mailto:C.Klaij at marin.nl |
> http://www.marin.nl
> >>
> >> MARIN news: http://www.marin.nl/web/News/News-items/The-Ocean-Cleanup-
> testing-continues.htm
> >>
> >> ________________________________________
> >> From: Barry Smith <bsmith at mcs.anl.gov>
> >> Sent: Friday, January 13, 2017 7:51 PM
> >> To: Klaij, Christiaan
> >> Cc: petsc-users at mcs.anl.gov
> >> Subject: Re: [petsc-users] monitoring the convergence of fieldsplit 0
> and 1
> >>
> >> Yes, I would have expected this to work. Could you send the output
> from -ksp_view in this case?
> >>
> >>
> >>> On Jan 13, 2017, at 3:46 AM, Klaij, Christiaan <C.Klaij at marin.nl>
> wrote:
> >>>
> >>> Barry,
> >>>
> >>> It's been a while but I'm finally using this function in
> >>> 3.7.4. Is it supposed to work with fieldsplit? Here's why.
> >>>
> >>> I'm solving a Navier-Stokes system with fieldsplit (pc has one
> >>> velocity solve and one pressure solve) and trying to retrieve the
> >>> totals like this:
> >>>
> >>> CALL KSPSolve(ksp_system,rr_system,xx_system,ierr); CHKERRQ(ierr)
> >>> CALL PCFieldSplitGetSubKSP(pc_system,numsplit,subksp,ierr);
> CHKERRQ(ierr)
> >>> CALL KSPGetTotalIterations(subksp(1),nusediter_vv,ierr); CHKERRQ(ierr)
> >>> CALL KSPGetTotalIterations(subksp(2),nusediter_pp,ierr); CHKERRQ(ierr)
> >>> print *, 'nusediter_vv', nusediter_vv
> >>> print *, 'nusediter_pp', nusediter_pp
> >>>
> >>> Running the code shows this surprise:
> >>>
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 1
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 1
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 2
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 2
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 7
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >>> Linear sys_fieldsplit_0_ solve converged due to CONVERGED_RTOL
> iterations 8
> >>>
> >>> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 22
> >>> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 6
> >>> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 3
> >>> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 2
> >>> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 2
> >>> Linear sys_fieldsplit_1_ solve converged due to CONVERGED_RTOL
> iterations 2
> >>>
> >>> nusediter_vv 37
> >>> nusediter_pp 37
> >>>
> >>> So the value of nusediter_pp is indeed 37, but for nusediter_vv
> >>> it should be 66. Any idea what went wrong?
> >>>
> >>> Chris
> >>>
> >>>
> >>>
> >>> dr. ir. Christiaan Klaij | CFD Researcher | Research & Development
> >>> MARIN | T +31 317 49 33 44 | mailto:C.Klaij at marin.nl |
> http://www.marin.nl
> >>>
> >>> MARIN news: http://www.marin.nl/web/News/
> News-items/MARIN-wishes-you-a-challenging-inspiring-2017.htm
> >>>
> >>> ________________________________________
> >>> From: Barry Smith <bsmith at mcs.anl.gov>
> >>> Sent: Saturday, April 11, 2015 12:27 AM
> >>> To: Klaij, Christiaan
> >>> Cc: petsc-users at mcs.anl.gov
> >>> Subject: Re: [petsc-users] monitoring the convergence of fieldsplit 0
> and 1
> >>>
> >>> Chris,
> >>>
> >>> I have added KSPGetTotalIterations() to the branch barry/add-ksp-total-iterations/master
> and next. After tests it will go into master
> >>>
> >>> Barry
> >>>
> >>>> On Apr 10, 2015, at 8:07 AM, Klaij, Christiaan <C.Klaij at marin.nl>
> wrote:
> >>>>
> >>>> Barry,
> >>>>
> >>>> Sure, I can call PCFieldSplitGetSubKSP() to get the fieldsplit_0
> >>>> ksp and then KSPGetIterationNumber, but what does this number
> >>>> mean?
> >>>>
> >>>> It appears to be the number of iterations of the last time that
> >>>> the subsystem was solved, right? If so, this corresponds to the
> >>>> last iteration of the coupled system, how about all the previous
> >>>> iterations?
> >>>>
> >>>> Chris
> >>>> ________________________________________
> >>>> From: Barry Smith <bsmith at mcs.anl.gov>
> >>>> Sent: Friday, April 10, 2015 2:48 PM
> >>>> To: Klaij, Christiaan
> >>>> Cc: petsc-users at mcs.anl.gov
> >>>> Subject: Re: [petsc-users] monitoring the convergence of fieldsplit 0
> and 1
> >>>>
> >>>> Chris,
> >>>>
> >>>> It appears you should call PCFieldSplitGetSubKSP() and then get the
> information you want out of the individual KSPs. If this doesn't work
> please let us know.
> >>>>
> >>>> Barry
> >>>>
> >>>>> On Apr 10, 2015, at 6:48 AM, Klaij, Christiaan <C.Klaij at marin.nl>
> wrote:
> >>>>>
> >>>>> A question when using PCFieldSplit: for each linear iteration of
> >>>>> the system, how many iterations for fielsplit 0 and 1?
> >>>>>
> >>>>> One way to find out is to run with -ksp_monitor,
> >>>>> -fieldsplit_0_ksp_monitor and -fieldsplit_0_ksp_monitor. This
> >>>>> gives the complete convergence history.
> >>>>>
> >>>>> Another way, suggested by Matt, is to use -ksp_monitor,
> >>>>> -fieldsplit_0_ksp_converged_reason and
> >>>>> -fieldsplit_1_ksp_converged_reason. This gives only the totals
> >>>>> for fieldsplit 0 and 1 (but without saying for which one).
> >>>>>
> >>>>> Both ways require to somehow process the output, which is a bit
> >>>>> inconvenient. Could KSPGetResidualHistory perhaps return (some)
> >>>>> information on the subsystems' convergence for processing inside
> >>>>> the code?
> >>>>>
> >>>>> Chris
> >>>>>
> >>>>>
> >>>>> dr. ir. Christiaan Klaij
> >>>>> CFD Researcher
> >>>>> Research & Development
> >>>>> E mailto:C.Klaij at marin.nl
> >>>>> T +31 317 49 33 44
> >>>>>
> >>>>>
> >>>>> MARIN
> >>>>> 2, Haagsteeg, P.O. Box 28, 6700 AA Wageningen, The Netherlands
> >>>>> T +31 317 49 39 11, F +31 317 49 32 45, I www.marin.nl
> >>>>>
> >>>>
> >>>
> >>
> >
>
>
--
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
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