poisson_nonlinear
  Solve a nonlinear Poisson equation.
No Jacobian form specified for nonlinear variational problem.
Differentiating residual form F to obtain Jacobian J = F'.
Calling FFC just-in-time (JIT) compiler, this may take some time.
Calling FFC just-in-time (JIT) compiler, this may take some time.
Calling FFC just-in-time (JIT) compiler, this may take some time.
Solving nonlinear variational problem.
  Newton iteration 0: r (abs) = 1.776e+01 (tol = 1.000e-10) r (rel) = 1.000e+00 (tol = 1.000e-06)
  Newton iteration 1: r (abs) = 9.035e-03 (tol = 1.000e-10) r (rel) = 5.087e-04 (tol = 1.000e-06)
  Newton iteration 2: r (abs) = 2.718e-04 (tol = 1.000e-10) r (rel) = 1.530e-05 (tol = 1.000e-06)
  Newton iteration 3: r (abs) = 1.267e-07 (tol = 1.000e-10) r (rel) = 7.130e-09 (tol = 1.000e-06)
  Newton solver finished in 3 iterations and 3 linear solver iterations.
Grpahics saved as "poisson_nonlinear_solution.png"
Object cannot be plotted directly, projecting to piecewise linears.
Calling FFC just-in-time (JIT) compiler, this may take some time.
Calling FFC just-in-time (JIT) compiler, this may take some time.
Calling FFC just-in-time (JIT) compiler, this may take some time.
Graphics saved as "poisson_nonlinear_gradient.png"

poisson_nonlinear
  Normal end of execution.