#include <SimpleNewtonNonlinearSolver.hpp>

Inheritance diagram for SimpleNewtonNonlinearSolver:

Collaboration diagram for SimpleNewtonNonlinearSolver:

Public Member Functions
	SimpleNewtonNonlinearSolver ()

virtual	~SimpleNewtonNonlinearSolver ()

virtual Vec	Solve (PetscErrorCode(pComputeResidual)(SNES, Vec, Vec, void ), PetscErrorCode(pComputeJacobian)(SNES, Vec, Mat , Mat , MatStructure , void ), Vec initialGuess, unsigned fill, void pContext)

void	SetTolerance (double tolerance)

void	SetWriteStats (bool writeStats=true)

Public Member Functions inherited from AbstractNonlinearSolver
virtual	~AbstractNonlinearSolver ()

Private Attributes
double	mTolerance

bool	mWriteStats

std::vector< double >	mTestDampingValues

Detailed Description

A solver class that uses Newton's method with damping.

Definition at line 46 of file SimpleNewtonNonlinearSolver.hpp.

Constructor & Destructor Documentation

SimpleNewtonNonlinearSolver::SimpleNewtonNonlinearSolver ( )

Constructor.

Definition at line 41 of file SimpleNewtonNonlinearSolver.cpp.

References mTestDampingValues.

SimpleNewtonNonlinearSolver::~SimpleNewtonNonlinearSolver ( )

virtual

Destructor.

Definition at line 54 of file SimpleNewtonNonlinearSolver.cpp.

Member Function Documentation

void SimpleNewtonNonlinearSolver::SetTolerance ( double tolerance )

Set a tolerance other than the default.

Parameters

tolerance

Definition at line 174 of file SimpleNewtonNonlinearSolver.cpp.

References mTolerance.

void SimpleNewtonNonlinearSolver::SetWriteStats ( bool writeStats = true )

inline

Call to set the solver to write details as it solves.

Parameters

writeStats defaults to true

Definition at line 137 of file SimpleNewtonNonlinearSolver.hpp.

References mWriteStats.

Vec SimpleNewtonNonlinearSolver::Solve	(	PetscErrorCode()(SNES, Vec, Vec, void )	pComputeResidual,
		PetscErrorCode()(SNES, Vec, Mat , Mat , MatStructure , void *)	pComputeJacobian,
		Vec	initialGuess,
		unsigned	fill,
		void *	pContext
	)

virtual

Solve().

Solve a nonlinear system using Newton's method with damping. Newton's algorithm is

x_new = x_old - J^{-1} f

where J is the Jacobian matrix evaluated at x_old and f the residual evaluated at x_old. The Newton method with damping is

x_new = x_old - s J^{-1} f

where s is some damping factor. Here s is chosen by just looked at a fixed set of possible damping factors and choosing the one which gives the best x_new (the one for which the residual evaluated at x_new has the lowest norm).

The solver quits once the ||f||/numVariables

Parameters

pComputeResidual	points to the function which computes the residual, it must take arguments SNES (a PETSc nonlinear solver object), Vec (current guess - a vector of the correct size), Vec (a Vec of the correct size in which the residual is returned), void* (a pointer to anything you may need to refer to when calculating the residual)
pComputeJacobian	points to the function which computes the Jacobian, it must take arguments SNES (a PETSc nonlinear solver * object), Mat* (a pointer to the Jacobian matrix) ,Mat* (a pointer to a preconditioner matrix), MatStructure* (points to the PETSc matrix type e.g. AIJ), void* (a pointer to anything you may need to refer to when calculating the residual).
initialGuess	A PETSc Vec of the correct size, containing initial guesses for the nonlinear solver.
pContext	[optional] A pointer to a class that may have to be used in the ComputeResidual and ComputeJacobian functions
fill	the expected maximum number of nonzeros in a row of the Jacobian matrix