itk::fem::Solver Class Reference

#include <itkFEMSolver.h>

Inheritance diagram for itk::fem::Solver:

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Collaboration diagram for itk::fem::Solver:

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List of all members.

Detailed Description

Main FEM solver.

This is the main class used for solving the FEM problems. It also stores all the objects that define the specific FEM problem. Normally there is one Solver object for each FEM problem.

Definition at line 41 of file itkFEMSolver.h.


Public Types
typedef Element::ArrayType	ElementArray
typedef Element::Float	Float
typedef itk::Image < Element::ConstPointer, MaxGridDimensions >	InterpolationGridType
typedef Load::ArrayType	LoadArray
typedef Material::ArrayType	MaterialArray
typedef Node::ArrayType	NodeArray
typedef Element::VectorType	VectorType
Public Member Functions
void	ApplyBC (int dim=0, unsigned int matrix=0)
virtual void	AssembleElementMatrix (Element::Pointer e)
void	AssembleF (int dim=0)
void	AssembleK (void)
virtual void	AssembleLandmarkContribution (Element::Pointer e, float)
virtual void	Clear (void)
void	DecomposeK (void)
virtual void	FinalizeMatrixAfterAssembly (void)
void	GenerateGFN (void)
Float	GetDeformationEnergy (unsigned int SolutionIndex=0)
const Element *	GetElementAtPoint (const VectorType &pt) const
const InterpolationGridType *	GetInterpolationGrid (void) const
LinearSystemWrapper::Pointer	GetLinearSystemWrapper ()
unsigned int	GetNumberOfDegreesOfFreedom (void)
Float	GetSolution (unsigned int i, unsigned int which=0)
virtual Float	GetTimeStep (void) const
void	InitializeInterpolationGrid (const VectorType &size, const VectorType &bb1, const VectorType &bb2)
virtual void	InitializeLinearSystemWrapper (void)
virtual void	InitializeMatrixForAssembly (unsigned int N)
	itkStaticConstMacro (MaxGridDimensions, unsigned int, 3)
void	Read (std::istream &f)
void	SetLinearSystemWrapper (LinearSystemWrapper::Pointer ls)
virtual void	SetTimeStep (Float)
virtual void	Solve (void)
	Solver ()
void	UpdateDisplacements (void)
void	Write (std::ostream &f)
virtual	~Solver ()

void	InitializeInterpolationGrid (const VectorType &size)
Public Attributes
ElementArray	el
LoadArray	load
MaterialArray	mat
NodeArray	node
Protected Attributes
LinearSystemWrapper::Pointer	m_ls
unsigned int	NGFN
unsigned int	NMFC

Member Typedef Documentation

typedef Element::ArrayType itk::fem::Solver::ElementArray

Array that holds pointers to all elements. since we want to be able to manipulate the array we have to use special pointers

Definition at line 54 of file itkFEMSolver.h.

typedef Element::Float itk::fem::Solver::Float

Local float type

Definition at line 48 of file itkFEMSolver.h.

typedef itk::Image<Element::ConstPointer,MaxGridDimensions> itk::fem::Solver::InterpolationGridType

Type used to store interpolation grid

Definition at line 95 of file itkFEMSolver.h.

typedef Load::ArrayType itk::fem::Solver::LoadArray

Array that holds special pointers to all external loads

Definition at line 66 of file itkFEMSolver.h.

typedef Material::ArrayType itk::fem::Solver::MaterialArray

Array that holds pointers to the materials

Definition at line 72 of file itkFEMSolver.h.

typedef Node::ArrayType itk::fem::Solver::NodeArray

Array that holds special pointers to the nodes

Definition at line 60 of file itkFEMSolver.h.

typedef Element::VectorType itk::fem::Solver::VectorType

VectorType from the Element base class

Definition at line 78 of file itkFEMSolver.h.

Constructor & Destructor Documentation

itk::fem::Solver::Solver ( )

Default constructor sets Solver to use VNL linear system .

See also:: Solver::SetLinearSystemWrapper

virtual itk::fem::Solver::~Solver ( ) [inline, virtual]

Virtual destructor

Definition at line 275 of file itkFEMSolver.h.

Member Function Documentation

void itk::fem::Solver::ApplyBC	(	int	dim = `0`,
		unsigned int	matrix = `0`
	)

Apply the boundary conditions to the system.

Note:: This function must be called after AssembleK().

Parameters:

	matrix	Index of a matrix, to which the BCs should be applied (master stiffness matrix). Normally this is zero, but in derived classes many matrices may be used and this index must be specified.
	dim	This is a parameter that can be passed to the function and is normally used with isotropic elements to specify the dimension in which the DOF is fixed.

Referenced by FinalizeMatrixAfterAssembly().

virtual void itk::fem::Solver::AssembleElementMatrix ( Element::Pointer e ) [virtual]

Copy the element stiffness matrix into the correct position in the master stiffess matrix. Since more complex Solver classes may need to assemble many matrices and may also do some funky stuff to them, this function is virtual and can be overriden in a derived solver class.

Reimplemented in itk::fem::SolverHyperbolic.

void itk::fem::Solver::AssembleF ( int dim = 0 )

Assemble the master force vector.

Parameters:

dim

This is a parameter that can be passed to the function and is normally used with isotropic elements to specify the dimension for which the master force vector should be assembled.

void itk::fem::Solver::AssembleK ( void )

Assemble the master stiffness matrix (also apply the MFCs to K)

virtual void itk::fem::Solver::AssembleLandmarkContribution	(	Element::Pointer	e,
		float
	)			`[virtual]`

Add the contribution of the landmark-containing elements to the correct position in the master stiffess matrix. Since more complex Solver classes may need to assemble many matrices and may also do some funky stuff to them, this function is virtual and can be overriden in a derived solver class.

virtual void itk::fem::Solver::Clear ( void ) [virtual]

Cleans all data members, and initializes the solver to initial state.

void itk::fem::Solver::DecomposeK ( void )

Decompose matrix using svd, qr, whatever ...

virtual void itk::fem::Solver::FinalizeMatrixAfterAssembly ( void ) [inline, virtual]

This function is called after the assebly has been completed. In this class it is only used to apply the BCs. You may however use it to perform other stuff in derived solver classes.

Reimplemented in itk::fem::SolverHyperbolic.

Definition at line 189 of file itkFEMSolver.h.

References ApplyBC().

void itk::fem::Solver::GenerateGFN ( void )

System solver functions. Call all six functions below (in listed order) to solve system. Assign a global freedom numbers to each DOF in a system. This must be done before any other solve function can be called.

Float itk::fem::Solver::GetDeformationEnergy ( unsigned int SolutionIndex = 0 )

Get the total deformation energy using the chosen solution

const Element* itk::fem::Solver::GetElementAtPoint ( const VectorType & pt ) const

Returns the pointer to the element which contains global point pt.

Parameters:

pt

Point in global coordinate system.

Note:: Interpolation grid must be initializes before you can call this function.

const InterpolationGridType* itk::fem::Solver::GetInterpolationGrid ( void ) const [inline]

Returns pointer to interpolation grid, which is an itk::Image of pointers to Element objects. Normally you would use physical coordinates to get specific points (pointers to elements) from the image. You can then use the Elemenet::InterpolateSolution member function on the returned element to obtain the solution at this point.

Note:: Physical coordinates in an image correspond to the global coordinate system in which the mesh (nodes) are.

Definition at line 132 of file itkFEMSolver.h.

References itk::SmartPointer< TObjectType >::GetPointer().

LinearSystemWrapper::Pointer itk::fem::Solver::GetLinearSystemWrapper ( ) [inline]

Gets the LinearSystemWrapper object.

See also:: SetLinearSystemWrapper

Definition at line 298 of file itkFEMSolver.h.

References m_ls.

unsigned int itk::fem::Solver::GetNumberOfDegreesOfFreedom ( void ) [inline]

Definition at line 257 of file itkFEMSolver.h.

References NGFN.

Float itk::fem::Solver::GetSolution	(	unsigned int	i,
		unsigned int	which = `0`
	)			`[inline]`

Definition at line 252 of file itkFEMSolver.h.

References itk::fem::Solution::GetSolutionValue(), and m_ls.

virtual Float itk::fem::Solver::GetTimeStep ( void ) const [inline, virtual]

Returns the time step used for dynamic problems.

Reimplemented in itk::fem::SolverHyperbolic.

Definition at line 309 of file itkFEMSolver.h.

void itk::fem::Solver::InitializeInterpolationGrid ( const VectorType & size ) [inline]

Same as InitializeInterpolationGrid(size, {0,0...}, size);

Definition at line 116 of file itkFEMSolver.h.

References InitializeInterpolationGrid().

void itk::fem::Solver::InitializeInterpolationGrid	(	const VectorType &	size,
		const VectorType &	bb1,
		const VectorType &	bb2
	)

Initialize the interpolation grid. The interpolation grid is used to find elements that containg specific points in a mesh. The interpolation grid stores pointers to elements for each point on a grid thereby providing a fast way (lookup table) to perform interpolation of results.

Note:: Interpolation grid must be reinitialized each time a mesh changes.

Parameters:

	size	Vector that represents number of points on a grid in each dimension.
	bb1	Lower limit of a bounding box of a grid.
	bb2	Upper limit of a bounding box of a grid.

See also:: GetInterpolationGrid

Referenced by InitializeInterpolationGrid().

virtual void itk::fem::Solver::InitializeLinearSystemWrapper ( void ) [virtual]

Performs any initialization needed for LinearSystemWrapper object i.e. sets the maximum number of matrices and vectors.

Reimplemented in itk::fem::SolverHyperbolic.

virtual void itk::fem::Solver::InitializeMatrixForAssembly ( unsigned int N ) [virtual]

This function is called before assembling the matrices. You can override it in a derived class to account for special needs.

Parameters:

N

Size of the matrix.

Reimplemented in itk::fem::SolverHyperbolic.

itk::fem::Solver::itkStaticConstMacro	(	MaxGridDimensions	,
		unsigned	int,
		3
	)

Since the itk::Image is templated over the number of dimensions, we have to know this at compile time. Solver class, however, can handle elements in any number of dimensions. In order to be able to use the Image, we choose the maximum number of space dimension that this function will be able to handle. Any unused dimensions are filled with zero.

For example: If a 2D node coordinates are {1.0,3.0} then the corresponding phisycal point in an image is {1.0,3.0,0.0};

void itk::fem::Solver::Read ( std::istream & f )

Reads the whole system (nodes, materials and elements) from input stream

void itk::fem::Solver::SetLinearSystemWrapper ( LinearSystemWrapper::Pointer ls )

Sets the LinearSystemWrapper object that will be used when solving the master equation. If this function is not called, a default VNL linear system representation will be used (class LinearSystemWrapperVNL).

Parameters:

ls

Pointer to an object of class which is derived from LinearSystemWrapper.

Note:: Once the LinearSystemWrapper object is changed, it is used until the member function SetLinearSystemWrapper is called again. Since LinearSystemWrapper object was created outside the Solver class, it should also be destroyed outside. Solver class will not destroy it when the Solver object is destroyed.

virtual void itk::fem::Solver::SetTimeStep ( Float ) [inline, virtual]

Sets the time step used for dynamic problems.

Parameters:

dt

New time step.

Definition at line 316 of file itkFEMSolver.h.

virtual void itk::fem::Solver::Solve ( void ) [virtual]

Solve for the displacement vector u. May be overriden in derived classes.

Reimplemented in itk::fem::SolverHyperbolic.

void itk::fem::Solver::UpdateDisplacements ( void )

Copy solution vector u to the corresponding nodal values, which are stored in node objects). This is standard post processing of the solution

void itk::fem::Solver::Write ( std::ostream & f )