Hello everyone,
I am using the snes composite with the following options:
-snes_type composite
-snes_composite_type multiplicative
-snes_composite_sneses newtonls
-snes_linesearch_type bt
-sub_0_snes_linesearch_type basic
-snes_linesearch_monitor
-sub_0_snes_linesearch_monitor
I only use single newtonls in the composite for helping me understand how
the composite works. By specifying the -snes_linesearch_type bt, I am
expecting the norm decrease in each iterations. Moreover,
-snes_linesearch_monitor should print the information on the step size.
However, when I ran the codes, I found that no information on the step size
of linesearch is output and the residual norm sometimes is NOT decreasing
given the bt option provided. It seems that the snes_linesearch_bt is not
working in this setting or I messed up the options somewhere.
The linesearch works in the sub_0 level if I specify
the -sub_0_snes_linesearch_type bt. I do not understand why it does not
work in the overall level.
Here is the snes norm information as well as the output of snes_view. Is
there a way to get the linesearch working on the overall level?
0 SNES Function norm 1.436371027798e+04
0 SNES Function norm 1.436371027798e+04
1 SNES Function norm 1.562640838177e+04
1 SNES Function norm 1.562640838177e+04
0 SNES Function norm 1.562640838177e+04
1 SNES Function norm 5.101254678006e+03
2 SNES Function norm 5.101254678006e+03
0 SNES Function norm 5.101254678006e+03
1 SNES Function norm 1.287999851800e+03
3 SNES Function norm 1.287999851800e+03
0 SNES Function norm 1.287999851800e+03
1 SNES Function norm 3.781864044552e+02
4 SNES Function norm 3.781864044552e+02
0 SNES Function norm 3.781864044552e+02
1 SNES Function norm 9.895411709407e+01
5 SNES Function norm 9.895411709407e+01
0 SNES Function norm 9.895411709407e+01
1 SNES Function norm 6.379856588223e+00
6 SNES Function norm 6.379856588223e+00
Nonlinear solve converged due to CONVERGED_FNORM_RELATIVE iterations 6
SNES Object: 256 MPI processes
type: composite
Composite SNES type - MULTIPLICATIVE
SNESes on composite preconditioner follow
---------------------------------
SNES Object: (sub_0_) 256 MPI processes
type: newtonls
maximum iterations=1, maximum function evaluations=10000
tolerances: relative=1e-08, absolute=1e-50, solution=1e-08
total number of linear solver iterations=188
total number of function evaluations=1
SNESLineSearch Object: (sub_0_) 256 MPI processes
type: basic
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: (sub_0_) 256 MPI processes
type: bcgsl
BCGSL: Ell = 2
BCGSL: Delta = 0
maximum iterations=5000, initial guess is zero
tolerances: relative=0.001, absolute=1e-50, divergence=10000
left preconditioning
using PRECONDITIONED norm type for convergence test
PC Object: (sub_0_) 256 MPI processes
type: sor
SOR: type = local_symmetric, iterations = 1, local iterations =
1, omega = 1
linear system matrix = precond matrix:
Mat Object: jac 256 MPI processes
type: mpiaij
rows=2244000, cols=2244000, bs=2
total: nonzeros=3.112e+07, allocated nonzeros=3.112e+07
total number of mallocs used during MatSetValues calls =0
---------------------------------
maximum iterations=10, maximum function evaluations=10000
tolerances: relative=0.001, absolute=1e-50, solution=1e-08
total number of linear solver iterations=0
total number of function evaluations=1
SNESLineSearch Object: 256 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: 256 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=1e-05, absolute=1e-50, divergence=10000
left preconditioning
using DEFAULT norm type for convergence test
PC Object: 256 MPI processes
type: lu
PC has not been set up so information may be incomplete
LU: out-of-place factorization
tolerance for zero pivot 2.22045e-14
matrix ordering: natural
Thank you.
Best,
Xiangdong
