[petsc-users] Problem about DIVERGED_FUNCTION_COUNT

[Yingjie Wu]

Dear Petsc developer:
Hi,

Thank you very much for your previous reply .

I recently wrote an example of neutron diffusion, which shows that the
nonlinear residuals are gradually decreasing, but the program terminates in
the tenth step of the nonlinear step.The program output information is as
follows.


-snes_fd -pc_type lu -snes_view -snes_converged_reason -snes_monitor_cancel
-ksp_converged_reason -ksp_monitor_true_residual


iter = 0, SNES Function norm 0.999045 0 KSP preconditioned resid norm
1.143042621777e+02 true resid norm 9.990445435144e-01 ||r(i)||/||b||
1.000000000000e+00 1 KSP preconditioned resid norm 2.250033129078e-12 true
resid norm 3.772661181818e-14 ||r(i)||/||b|| 3.776269242757e-14 Linear
solve converged due to CONVERGED_RTOL iterations 1 iter = 1, SNES Function
norm 0.863398 0 KSP preconditioned resid norm 3.176569252473e+00 true resid
norm 8.633978674995e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP
preconditioned resid norm 7.360979829512e-14 true resid norm
1.835881897914e-14 ||r(i)||/||b|| 2.126345184557e-14 Linear solve converged
due to CONVERGED_RTOL iterations 1 iter = 2, SNES Function norm 0.217885 0
KSP preconditioned resid norm 5.796196387015e+01 true resid norm
2.178851605144e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 9.643306967470e-13 true resid norm 3.884638811957e-14
||r(i)||/||b|| 1.782883608405e-13 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 3, SNES Function norm 0.217871 0 KSP
preconditioned resid norm 3.792350832110e+01 true resid norm
2.178711262680e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 1.369102629758e-12 true resid norm 1.632695466260e-13
||r(i)||/||b|| 7.493858843196e-13 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 4, SNES Function norm 0.217839 0 KSP
preconditioned resid norm 2.467674567895e+01 true resid norm
2.178387732479e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 1.336018611676e-12 true resid norm 2.369440379931e-14
||r(i)||/||b|| 1.087703692324e-13 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 5, SNES Function norm 0.217793 0 KSP
preconditioned resid norm 1.325333377704e+01 true resid norm
2.177933144217e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 2.663121116220e-13 true resid norm 6.399802508715e-15
||r(i)||/||b|| 2.938475189519e-14 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 6, SNES Function norm 0.217546 0 KSP
preconditioned resid norm 8.654271429945e+00 true resid norm
2.175456199462e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 2.103027422078e-12 true resid norm 1.896269373207e-14
||r(i)||/||b|| 8.716651586351e-14 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 7, SNES Function norm 0.217024 0 KSP
preconditioned resid norm 5.238463146996e+00 true resid norm
2.170240974179e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 1.538914082201e-13 true resid norm 1.398699322805e-14
||r(i)||/||b|| 6.444903305426e-14 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 8, SNES Function norm 0.215661 0 KSP
preconditioned resid norm 3.380654310210e+00 true resid norm
2.156611254980e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 5.676163043758e-14 true resid norm 2.209776803347e-15
||r(i)||/||b|| 1.024652355979e-14 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 9, SNES Function norm 0.213573 0 KSP
preconditioned resid norm 1.833370627403e+00 true resid norm
2.135728351107e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 1.237094085371e-13 true resid norm 3.167085089319e-15
||r(i)||/||b|| 1.482906329205e-14 Linear solve converged due to
CONVERGED_RTOL iterations 1 iter = 10, SNES Function norm 0.206951 0 KSP
preconditioned resid norm 1.011617991320e+00 true resid norm
2.069514796799e-01 ||r(i)||/||b|| 1.000000000000e+00 1 KSP preconditioned
resid norm 3.789650938118e-13 true resid norm 5.695302032970e-14
||r(i)||/||b|| 2.751998701231e-13 Linear solve converged due to
CONVERGED_RTOL iterations 1 Nonlinear solve did not converge due to
DIVERGED_FUNCTION_COUNT iterations 10 SNES Object: 1 MPI processes type:
newtonls maximum iterations=50, maximum function evaluations=10000
tolerances: relative=1e-08, absolute=1e-50, solution=1e-08 total number of
linear solver iterations=11 total number of function evaluations=10623 norm
schedule ALWAYS Jacobian is built using finite differences one column at a
time SNESLineSearch Object: 1 MPI processes type: bt interpolation: cubic
alpha=1.000000e-04 maxstep=1.000000e+08, minlambda=1.000000e-12 tolerances:
relative=1.000000e-08, absolute=1.000000e-15, lambda=1.000000e-08 maximum
iterations=40 KSP Object: 1 MPI processes type: gmres restart=30, using
Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative
refinement happy breakdown tolerance 1e-30 maximum iterations=10000,
initial guess is zero tolerances: relative=1e-05, absolute=1e-50,
divergence=10000. left preconditioning using PRECONDITIONED norm type for
convergence test PC Object: 1 MPI processes type: lu out-of-place
factorization tolerance for zero pivot 2.22045e-14 matrix ordering: nd
factor fill ratio given 5., needed 5.81047 Factored matrix follows: Mat
Object: 1 MPI processes type: seqaij rows=961, cols=961 package used to
perform factorization: petsc total: nonzeros=38169, allocated
nonzeros=38169 total number of mallocs used during MatSetValues calls =0
not using I-node routines linear system matrix = precond matrix: Mat
Object: 1 MPI processes type: seqaij rows=961, cols=961 total:
nonzeros=6569, allocated nonzeros=15485 total number of mallocs used during
MatSetValues calls =712 not using I-node routines



I don't know why the program was terminated. I really need your help.

Thanks,
Yingjie
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