# NonlinearProblem¶

class dolfin.cpp.la.NonlinearProblem

Bases: object

This is a base class for nonlinear problems which can return the nonlinear function F(u) and its Jacobian J = dF(u)/du.

Constructor.

F()

Compute F at current point x.

Parameters: & b (GenericVector) – GenericVector & x (const) – void
J()

Compute J = F’ at current point x.

Parameters: & A (GenericMatrix) – GenericVector & x (const) – void
J_pc()

Compute J_pc used to precondition J. Not implementing this or leaving P empty results in system matrix A being used to construct preconditioner. Note that if nonempty P is not assembled on first call then a solver implementation may throw away P and not call this routine ever again.

Parameters: & P (GenericMatrix) – GenericVector & x (const) – void
form()

Function called by Newton solver before requesting F or J. This can be used to compute F and J together. NOTE: This function is deprecated. Use variant with preconditioner

Parameters: & A (GenericMatrix) – & b (GenericVector) – GenericVector & x (const) – void
thisown

The membership flag