I have solved a set of nonlinear PDEs using the NonlinearImplicitSystem and
PetscNonlinearSolver. It works very well.
Now I am using nearly the same code to solve some other PDEs, for the
first pressure step(increase external pressure at each step), my code just
stops at the first nonlinear step. and for the second pressure step, it
stops at zero nonlinear step.
The following is the output of my code.
NL step 0, |residual|_2 = 2.339308e-01
NL step 1, |residual|_2 = 1.047855e-01
NL step 0, |residual|_2 = 1.048353e-01
I only specified the nonlinear solver tolerance (1.e-12)and nonlinear solver
maxium iterations (100) as example 19 did. Then I tried to change the
nonlinear steps in ex19, if i let nonlinear solver maximum iterations = 2 or
100, it seems no effect on the code.
I have noticed that there are some nonlinear tolerance to specify. What are
the default value of the nonliner tolerances? What is the stopping
could anyone tell me how should I control the nonlinear steps?