itk::fem::Solver Class Reference

Main FEM solver. More...

#include <itkFEMSolver.h>

Inheritance diagram for itk::fem::Solver:

[legend]Collaboration diagram for itk::fem::Solver:

[legend]List of all members.

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

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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.

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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. Referenced by itk::fem::SolverHyperbolic::GetTimeStep(), itk::fem::SolverCrankNicolson::GSMax(), itk::fem::SolverHyperbolic::SetTimeStep(), and itk::fem::SolverCrankNicolson::~SolverCrankNicolson().

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. Referenced by InitializeInterpolationGrid().

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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 267 of file itkFEMSolver.h.

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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::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    )

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.

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

Gets the LinearSystemWrapper object. See also: SetLinearSystemWrapper Definition at line 290 of file itkFEMSolver.h.

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

Definition at line 249 of file itkFEMSolver.h. References NGFN.

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

Definition at line 244 of file itkFEMSolver.h. References 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 301 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(), and VectorType.

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. Reimplemented in itk::fem::SolverHyperbolic. Definition at line 308 of file itkFEMSolver.h. References m_ls, NGFN, and NMFC.

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

Solve for the displacement vector u. May be overriden in derived classes. Reimplemented in itk::fem::SolverCrankNicolson, and 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 )

Writes everything (nodes, materials and elements) to output stream

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Member Data Documentation

ElementArray itk::fem::Solver::el

Definition at line 55 of file itkFEMSolver.h.

LoadArray itk::fem::Solver::load

Definition at line 67 of file itkFEMSolver.h.

LinearSystemWrapper::Pointer itk::fem::Solver::m_ls [protected]

Pointer to LinearSystemWrapper object. Definition at line 324 of file itkFEMSolver.h. Referenced by GetSolution(), itk::fem::SolverCrankNicolson::GSMax(), and SetTimeStep().

MaterialArray itk::fem::Solver::mat

Definition at line 73 of file itkFEMSolver.h.

unsigned int itk::fem::Solver::NGFN [protected]

Number of global degrees of freedom in a system Definition at line 315 of file itkFEMSolver.h. Referenced by GetNumberOfDegreesOfFreedom(), and SetTimeStep().

unsigned int itk::fem::Solver::NMFC [protected]

Number of multi freedom constraints in a system. This member is set in a AssembleK function. Definition at line 321 of file itkFEMSolver.h. Referenced by SetTimeStep().

NodeArray itk::fem::Solver::node

Definition at line 61 of file itkFEMSolver.h.

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The documentation for this class was generated from the following file:

• itkFEMSolver.h

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