[petsc-dev] TSComputeRHSJacobianConstant issue

Fri Feb 26 11:04:51 CST 2016

Hi all,

I'm running into problems with TS with a time independent, linear
rhs.  Following the user's manual, I use

ierr=TSSetProblemType(ts, TS_LINEAR);CHKERRQ(ierr);
ierr=TSSetRHSFunction(ts, 0, TSComputeRHSFunctionLinear, 0);CHKERRQ(ierr);
ierr=TSSetRHSJacobian(ts, mat, mat, TSComputeRHSJacobianConstant, 0);CHKERRQ(ierr);

But running the code I get:

[dmeiser at ivyamd src]$ ./sd -ts_monitor -snes_monitor -ksp_monitor_true_residual -snes_converged_reason -ts_type beuler -ts_max_steps 20 TS dt 0.01 time 0.
    0 SNES Function norm 1.433485640883e+00 
      0 KSP preconditioned resid norm 1.433485640883e-02 true resid norm 1.433485640883e+00 ||r(i)||/||b|| 1.000000000000e+00
      1 KSP preconditioned resid norm 6.528150237447e-18 true resid norm 6.122666587510e-16 ||r(i)||/||b|| 4.271173992185e-16
    1 SNES Function norm 1.419007435910e+02 
  Nonlinear solve converged due to CONVERGED_ITS iterations 1
1 TS dt 0.01 time 0.01
    0 SNES Function norm 1.433342292319e+02 
  Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE iterations 0
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR:  
[0]PETSC ERROR: TSStep has failed due to DIVERGED_NONLINEAR_SOLVE, increase -ts_max_snes_failures or make negative to attempt recovery
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Development GIT revision: pre-tsfc-330-gda8116b  GIT Date: 2016-02-23 15:17:17 -0600
[0]PETSC ERROR: ./sd on a cplx named ivyamd.txcorp.com by dmeiser Fri Feb 26 11:46:29 2016
[0]PETSC ERROR: Configure options --with-scalar-type=complex --with-x=0 --with-debugging=1 --with-ssl=0 --with-fortran-kernels=0 --with-pthread=0 --download-fftw=1 --with-mpi=1 --download-mpich=1 --with-mpiuni-fortran-binding=0 --with-fortran-interfaces
[0]PETSC ERROR: #1 TSStep() line 3346 in /scr_ivyamd/dmeiser/SD/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: #2 TSSolve() line 3544 in /scr_ivyamd/dmeiser/SD/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: #3 main() line 63 in /scr_ivyamd/dmeiser/SD/src/sd.c
[0]PETSC ERROR: PETSc Option Table entries:
[0]PETSC ERROR: -ksp_monitor_true_residual
[0]PETSC ERROR: -snes_converged_reason
[0]PETSC ERROR: -snes_monitor
[0]PETSC ERROR: -ts_max_steps 2
[0]PETSC ERROR: -ts_monitor
[0]PETSC ERROR: -ts_type beuler
[0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint at mcs.anl.gov----------
application called MPI_Abort(MPI_COMM_WORLD, 91) - process 0
[unset]: aborting job:
application called MPI_Abort(MPI_COMM_WORLD, 91) - process 0

It seems that the linear system is being solved just fine.  But
apparently it's the wrong linear problem because the SNES
function norm doesn't decrease.

I think the problem might be related to the following behaviour
of `scr/ts/examples/tutorials/ex3.c`:

[dmeiser at ivyamd tutorials]$ ./ex3 -nox -ts_type beuler -ts_max_steps 2 -ksp_converged_reason -snes_monitor
Solving a linear TS problem on 1 processor
Timestep   0: step size = 0.000143637, time = 0., 2-norm error = 1.01507e-15, max norm error = 3.10862e-15
    0 SNES Function norm 2.018485956680e+03 
    Linear solve converged due to CONVERGED_RTOL iterations 1
    1 SNES Function norm 1.207665524289e+05 
Timestep   1: step size = 0.000143637, time = 0.000143637, 2-norm error = 0.000599907, max norm error = 0.000863771
    0 SNES Function norm 1.195422385486e+05 
    Linear solve did not converge due to DIVERGED_PCSETUP_FAILED iterations 0
                   PCSETUP_FAILED due to FACTOR_NUMERIC_ZEROPIVOT 
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR:  
[0]PETSC ERROR: TSStep has failed due to DIVERGED_NONLINEAR_SOLVE, increase -ts_max_snes_failures or make negative to attempt recovery
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Development GIT revision: pre-tsfc-330-gda8116b  GIT Date: 2016-02-23 15:17:17 -0600
[0]PETSC ERROR: ./ex3 on a cplx named ivyamd.txcorp.com by dmeiser Fri Feb 26 11:36:28 2016
[0]PETSC ERROR: Configure options --with-scalar-type=complex --with-x=0 --with-debugging=1 --with-ssl=0 --with-fortran-kernels=0 --with-pthread=0 --download-fftw=1 --with-mpi=1 --download-mpich=1 --with-mpiuni-fortran-binding=0 --with-fortran-interfaces
[0]PETSC ERROR: #1 TSStep() line 3346 in /scr_ivyamd/dmeiser/SD/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: #2 TSSolve() line 3544 in /scr_ivyamd/dmeiser/SD/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: #3 main() line 216 in /scr_ivyamd/dmeiser/SD/petsc/src/ts/examples/tutorials/ex3.c
[0]PETSC ERROR: PETSc Option Table entries:
[0]PETSC ERROR: -ksp_converged_reason
[0]PETSC ERROR: -nox
[0]PETSC ERROR: -snes_monitor
[0]PETSC ERROR: -ts_max_steps 2
[0]PETSC ERROR: -ts_type beuler
[0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint at mcs.anl.gov----------
application called MPI_Abort(MPI_COMM_WORLD, 91) - process 0
[unset]: aborting job:
application called MPI_Abort(MPI_COMM_WORLD, 91) - process 0

I'm aware of Jed's commit e1244c6 which I thought was supposed to
enable constant linear rhs without IFunction and IJacobian.  Note
that e1244c6 also added tests that apparently produced very
different output (see e.g.
src/ts/examples/tutorials/output/ex3_4.out).

Is constant rhs without IFunction and IJacobian no longer
supported or did it just breat at some point?  Do I need to call
TSRHSJacobianSetReuse in addition to the lines of code above?  Is
it better to treat such systems using TSComputeIFunctionLinear
and TSComputeIJacobianConstant?

Thanks,
Dominic

-- 
Dominic Meiser
Tech-X Corporation - 5621 Arapahoe Avenue - Boulder, CO 80303