FEM_Matrix Class Reference

#include <getmatrix.h>

Inheritance diagram for FEM_Matrix:

Public Member Functions
	FEM_Matrix (Mesh const &mesh)
	FEM_Matrix (FEM_Matrix const &)=default
	~FEM_Matrix () override
void	Derive_Matrix_Pattern ()
void	Derive_Matrix_Pattern_fast ()
void	Derive_Matrix_Pattern_slow ()
void	CalculateLaplace (std::vector< double > &f)
void	ApplyDirichletBC (std::vector< double > const &u, std::vector< double > &f)
void	AddElem_3 (int const ial[3], double const ske[3][3], double const fe[3], std::vector< double > &f)
	‍**
Public Member Functions inherited from CRS_Matrix
	CRS_Matrix ()
	CRS_Matrix (CRS_Matrix const &)=default
virtual	~CRS_Matrix () override
void	GetDiag (std::vector< double > &d) const override
void	Mult (std::vector< double > &w, std::vector< double > const &u) const override
	‍**
void	Defect (std::vector< double > &w, std::vector< double > const &f, std::vector< double > const &u) const override
void	Debug () const override
int	fetch (int row, int col) const override
bool	Compare2Old (int nnode, int const id[], int const ik[], double const sk[]) const
Public Member Functions inherited from Matrix
	Matrix (int nrows, int ncols)
	Matrix (Matrix const &)=default
virtual	~Matrix ()
bool	isSquare () const
int	Nrows () const
int	Ncols () const
std::vector< double > const &	GetDiag () const

Private Attributes
Mesh const &	_mesh
	reference to discretization

Additional Inherited Members
Protected Attributes inherited from CRS_Matrix
int	_nnz
	number of non-zero entries
std::vector< int >	_id
	start indices of matrix rows
std::vector< int >	_ik
	column indices
std::vector< double >	_sk
	non-zero values
Protected Attributes inherited from Matrix
int	_nrows
	number of rows in matrix
int	_ncols
	number of columns in matrix
std::vector< double >	_dd
	diagonal matrix elements

Detailed Description

FEM Matrix in CRS format (compressed row storage; also named CSR), see an introduction.

Definition at line 235 of file getmatrix.h.

Constructor & Destructor Documentation

FEM_Matrix() [1/2]

FEM_Matrix::FEM_Matrix ( Mesh const &  mesh )

explicit

Initializes the CRS matrix structure from the given discretization in mesh.

The sparse matrix pattern is generated but the values are 0.

Parameters

[in]

mesh

given discretization

Warning

A reference to the discretization mesh is stored inside this class. Therefore, changing mesh outside requires also to call method Derive_Matrix_Pattern explicitly.

See also

Derive_Matrix_Pattern

Definition at line 184 of file getmatrix.cpp.

FEM_Matrix() [2/2]

FEM_Matrix::FEM_Matrix ( FEM_Matrix const &  )

default

~FEM_Matrix()

FEM_Matrix::~FEM_Matrix ( )

override

Destructor.

Definition at line 191 of file getmatrix.cpp.

Member Function Documentation

AddElem_3()

void FEM_Matrix::AddElem_3	(	int const	ial[3],
		double const	ske[3][3],
		double const	fe[3],
		std::vector< double > &	f
	)

‍**

Adds the element stiffness matrix ske and the element load vector fe of one triangular element with linear shape functions to the appropriate positions in the stiffness matrix, stored as CSR matrix K(sk,id, ik).

Parameters

[in]	ial	node indices of the three element vertices
[in]	ske	element stiffness matrix
[in]	fe	element load vector
[in,out]	f	distributed local vector storing the right hand side

Warning

Algorithm assumes linear triangular elements (ndof_e==3).

Definition at line 398 of file getmatrix.cpp.

ApplyDirichletBC()

void FEM_Matrix::ApplyDirichletBC	(	std::vector< double > const &	u,
		std::vector< double > &	f
	)

Applies Dirichlet boundary conditions to stiffness matrix and to load vector f. The penalty method is used for incorporating the given values u.

Parameters

[in]	u	(global) vector with Dirichlet data
[in,out]	f	load vector

Definition at line 366 of file getmatrix.cpp.

CalculateLaplace()

void FEM_Matrix::CalculateLaplace

(

std::vector< double > &

f

)

Calculates the entries of f.e. stiffness matrix and load/rhs vector f for the Laplace operator in 2D. No memory is allocated.

Parameters

[in,out]

f

(preallocated) rhs/load vector

Definition at line 308 of file getmatrix.cpp.

Derive_Matrix_Pattern()

void FEM_Matrix::Derive_Matrix_Pattern ( )

inline

Generates the sparse matrix pattern and overwrites the existing pattern.

The sparse matrix pattern is generated but the values are 0.

Definition at line 265 of file getmatrix.h.

Derive_Matrix_Pattern_fast()

void FEM_Matrix::Derive_Matrix_Pattern_fast

(

)

Definition at line 194 of file getmatrix.cpp.

Derive_Matrix_Pattern_slow()

void FEM_Matrix::Derive_Matrix_Pattern_slow

(

)

Definition at line 244 of file getmatrix.cpp.

Member Data Documentation

_mesh

Mesh const& FEM_Matrix::_mesh

private

reference to discretization

Definition at line 316 of file getmatrix.h.

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

• getmatrix.h
• getmatrix.cpp