nonlinear solvers

[Matthew Knepley]

On 2/12/07, Manav Bhatia <bhatiamanav at gmail.com> wrote:
> Hi,
>
>    I am using the nonlinear solvers in Petsc. My application requires
> the jacobian at the final nonlinear solution, since after the
> nonlinear solution I solve a linear system of equations with the
> jacobian as the system matrix.
>    I am curious to know if it is safe to assume that for all
> nonlinear solvers in Petsc, the last jacobian used before convergence
> is same as the jacobian evaluated at the final solution. If this is
> the case, then I will not need to evaluate the jacobian again,
> otherwise, I will need to compute it again after the final solution.

Never. We solve the Newton Equation, update the solution, and
THEN check for convergence. The Jacobian would not be updated.

   Matt

>    Kindly help me with your comments.
>
> Thanks,
> Manav
>
>


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