 # Newtoniteration output / see solution / initial data

Hello,
can someone explain me the output from the newton iteration??
I want to solve a nonlinear problem and use

``````solve(F == 0, m, bc)
yh, ph = m.split()
``````

And I have the following output. Can someone explain to me what this means?

No Jacobian form specified for nonlinear variational problem.
Differentiating residual form F to obtain Jacobian J = F’.
Solving nonlinear variational problem.
Newton iteration 0: r (abs) = 8.011e+01 (tol = 1.000e-10) r (rel) = 1.000e+00 (tol = 1.000e-09)
Newton iteration 1: r (abs) = 3.742e-01 (tol = 1.000e-10) r (rel) = 4.671e-03 (tol = 1.000e-09)
Newton iteration 2: r (abs) = 1.308e-03 (tol = 1.000e-10) r (rel) = 1.633e-05 (tol = 1.000e-09)
Newton iteration 3: r (abs) = 3.430e-08 (tol = 1.000e-10) r (rel) = 4.282e-10 (tol = 1.000e-09)
Newton solver finished in 3 iterations and 3 linear solver iterations.

Can i get the solutions output at each step?
And how is the start value chosen?

Thanks
Noya

See for example:
Newton’s method, The nonlinear Poisson demo and

The initial residual is constructed from whatever you pass for the solution vector. In the example you’ve provided `m.vector()`.

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