Detailed Description

template<typename Type>
class walberla::math::MatrixMxN< Type >

Efficient implementation of a $M \times N$ matrix.

The MatrixMxN class is the representation of a dynamic $M \times N$ matrix with a total of $M \cdot N$ dynamically allocated elements. These elements can be directly accessed with the 1D subscript operator or with the 2D function operator. The matrix is stored in a row-wise fashion:

        \f[\left(\begin{array}{*{5}{c}}
        0           & 1             & 2             & \cdots & N-1         \\
        N           & N+1           & N+2           & \cdots & 2 \cdot N-1 \\
        \vdots      & \vdots        & \vdots        & \ddots & \vdots      \\
        M \cdot N-N & M \cdot N-N+1 & M \cdot N-N+2 & \cdots & M \cdot N-1 \\
        \end{array}\right)\f]

MatrixMxN can be used with any non-cv-qualified element type. The arithmetic operators for matrix/matrix, matrix/vector and matrix/element operations with the same element type work for any element type as long as the element type supports the arithmetic operation. Arithmetic operations between matrices, vectors and elements of different element types are only supported for all data types supported by the MathTrait class template (for details see the MathTrait class description).

MatrixMxN< double > a, b, c;
MatrixMxN< float  > d;
MatrixMxN< std::complex<double> > e, f, g;
MatrixMxN< std::complex<float>  > h;
 
...         // Appropriate resizing
 
c = a + b;  // OK: Same element type, supported
c = a + d;  // OK: Different element types, supported by the MathTrait class template
 
g = e + f;  // OK: Same element type, supported
g = e + h;  // Error: Different element types, not supported by the MathTrait class template

#include <Types.h>

Public Types
using	This = MatrixMxN< Type >
	Type of this MatrixMxN instance. More...

using	ResultType = This
	Result type for expression template evaluations. More...

using	ElementType = Type
	Type of the matrix elements. More...

using	CompositeType = const MatrixMxN &
	Data type for composite expression templates. More...

Public Member Functions
template<typename Other , size_t M, size_t N>
MatrixMxN< Type > &	operator= (const Other(&rhs)[M][N])
	Array assignment to all matrix elements. More...

template<typename Other >
MatrixMxN< Type > &	scale (Other scalar)
	Scaling of the matrix by the scalar value scalar ( $A=B*s$ ). More...

Constructors
constexpr	MatrixMxN ()
	The default constructor for MatrixMxN. More...

constexpr	MatrixMxN (size_t m, size_t n)
	Constructor for a matrix of size $m \times n$ . More...

constexpr	MatrixMxN (size_t m, size_t n, Type init)
	Constructor for a homogenous initialization of all $m \times n$ matrix elements. More...

constexpr	MatrixMxN (const MatrixMxN &m)
	The copy constructor for MatrixMxN. More...

template<typename Other , size_t M, size_t N>
constexpr	MatrixMxN (const Other(&rhs)[M][N])
	Array initialization of all matrix elements. More...

Destructor
	~MatrixMxN ()
	The destructor for MatrixMxN. More...

Operators
template<typename Other , size_t M, size_t N>
MatrixMxN &	operator= (const Other(&rhs)[M][N])

MatrixMxN &	operator= (Type set)
	Homogenous assignment to all matrix elements. More...

MatrixMxN &	operator= (const MatrixMxN &set)
	Copy assignment operator for MatrixMxN. More...

Type &	operator[] (size_t index)
	1D-access to the matrix elements. More...

const Type &	operator[] (size_t index) const
	1D-access to the matrix elements. More...

Type &	operator() (size_t i, size_t j)
	2D-access to the matrix elements. More...

const Type &	operator() (size_t i, size_t j) const
	2D-access to the matrix elements. More...

Utility functions
size_t	rows () const
	Returns the current number of rows of the matrix. More...

size_t	columns () const
	Returns the current number of columns of the matrix. More...

size_t	capacity () const
	Returns the maximum capacity of the matrix. More...

size_t	nonZeros () const
	Returns the total number of non-zero elements in the matrix. More...

size_t	nonZeros (size_t i) const
	Returns the number of non-zero elements in the specified row. More...

void	reset ()
	Reset to the default initial values. More...

void	clear ()
	Clearing the $M \times N$ matrix. More...

void	resize (size_t m, size_t n, bool preserve=true)
	Changing the size of the matrix. More...

void	extend (size_t m, size_t n, bool preserve=true)
	Extending the size of the matrix. More...

void	reserve (size_t elements)
	Setting the minimum capacity of the matrix. More...

MatrixMxN &	transpose ()
	Transposing the matrix. More...

bool	isDiagonal () const
	Checks if the matrix is diagonal. More...

bool	isSymmetric () const
	Checks if the matrix is symmetric. More...

template<typename Other >
MatrixMxN &	scale (Other scalar)

void	swap (MatrixMxN &m)
	Swapping the contents of two matrices. More...

Expression template evaluation functions
template<typename Other >
bool	isAliased (const Other *alias) const
	Returns whether the matrix is aliased with the given address alias. More...

Private Attributes
Member variables
size_t	m_
	The current number of rows of the matrix. More...

size_t	n_
	The current number of columns of the matrix. More...

size_t	capacity_
	The maximum capacity of the matrix. More...

Type *WALBERLA_RESTRICT	v_
	The dynamically allocated matrix elements. More...

Member Typedef Documentation

◆ CompositeType

template<typename Type >

using walberla::math::MatrixMxN< Type >::CompositeType = const MatrixMxN &

Data type for composite expression templates.

◆ ElementType

template<typename Type >

using walberla::math::MatrixMxN< Type >::ElementType = Type

Type of the matrix elements.

◆ ResultType

template<typename Type >

using walberla::math::MatrixMxN< Type >::ResultType = This

Result type for expression template evaluations.

◆ This

template<typename Type >

using walberla::math::MatrixMxN< Type >::This = MatrixMxN<Type>

Type of this MatrixMxN instance.

Constructor & Destructor Documentation

◆ MatrixMxN() [1/5]

template<typename Type >

constexpr walberla::math::MatrixMxN< Type >::MatrixMxN

inlineexplicitconstexpr

The default constructor for MatrixMxN.

◆ MatrixMxN() [2/5]

template<typename Type >

constexpr walberla::math::MatrixMxN< Type >::MatrixMxN	(	size_t	m,
		size_t	n
	)

inlineexplicitconstexpr

Constructor for a matrix of size $m \times n$ .

No element initialization is performed!

Parameters

m	The number of rows of the matrix.
n	The number of columns of the matrix.

Note: This constructor is only responsible to allocate the required dynamic memory. No element initialization is performed!

◆ MatrixMxN() [3/5]

template<typename Type >

constexpr walberla::math::MatrixMxN< Type >::MatrixMxN	(	size_t	m,
		size_t	n,
		Type	init
	)

inlineexplicitconstexpr

Constructor for a homogenous initialization of all $m \times n$ matrix elements.

Parameters

m	The number of rows of the matrix.
n	The number of columns of the matrix.
init	The initial value of the matrix elements.

All matrix elements are initialized with the specified value.

◆ MatrixMxN() [4/5]

template<typename Type >

constexpr walberla::math::MatrixMxN< Type >::MatrixMxN ( const MatrixMxN< Type > & m )

inlineconstexpr

The copy constructor for MatrixMxN.

Parameters

m	Matrix to be copied.

The copy constructor is explicitly defined due to the required dynamic memory management and in order to enable/facilitate NRV optimization.

◆ MatrixMxN() [5/5]

template<typename Type >

template<typename Other , size_t M, size_t N>

constexpr walberla::math::MatrixMxN< Type >::MatrixMxN ( const Other(&) rhs[M][N] )

inlineconstexpr

Array initialization of all matrix elements.

Parameters

rhs	$M \times N$ dimensional array for the initialization.

Returns: Reference to the assigned matrix.

This constructor offers the option to directly initialize the elements of the matrix:

const real init[3][3] = { { 1, 2, 3 },
                          { 4, 5 },
                          { 7, 8, 9 } };
MatrixMxN<real> A = init;

The matrix is sized according to the size of the array and initialized with the given values. Missing values are initialized with zero (as e.g. the value 6 in the example).

◆ ~MatrixMxN()

template<typename Type >

walberla::math::MatrixMxN< Type >::~MatrixMxN

inline

The destructor for MatrixMxN.

Member Function Documentation

◆ capacity()

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::capacity

inline

Returns the maximum capacity of the matrix.

Returns: The capacity of the matrix.

◆ clear()

template<typename Type >

void walberla::math::MatrixMxN< Type >::clear

inline

Clearing the $M \times N$ matrix.

Returns: void

After the clear() function, the size of the matrix is 0.

◆ columns()

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::columns

inline

Returns the current number of columns of the matrix.

Returns: The number of columns of the matrix.

◆ extend()

template<typename Type >

void walberla::math::MatrixMxN< Type >::extend	(	size_t	m,
		size_t	n,
		bool	preserve = `true`
	)

inline

Extending the size of the matrix.

Parameters

m	Number of additional rows.
n	Number of additional columns.
preserve	true if the old values of the matrix should be preserved, false if not.

Returns: void

This function increases the matrix size by m rows and n columns. During this operation, new dynamic memory may be allocated in case the capacity of the matrix is too small. Therefore this function potentially changes all matrix elements. In order to preserve the old matrix values, the preserve flag can be set to true. However, new matrix elements are not initialized!

◆ isAliased()

template<typename Type >

template<typename Other >

bool walberla::math::MatrixMxN< Type >::isAliased ( const Other * alias ) const

inline

Returns whether the matrix is aliased with the given address alias.

Parameters

alias The alias to be checked.

Returns: true in case the alias corresponds to this matrix, false if not.

◆ isDiagonal()

template<typename Type >

bool walberla::math::MatrixMxN< Type >::isDiagonal

inline

Checks if the matrix is diagonal.

Returns: true if the matrix is diagonal, false if not.

This function tests whether the matrix is diagonal, i.e. if the non-diagonal elements are default elements. In case of integral or floating point data types, a diagonal matrix has the form

                 \f[\left(\begin{array}{*{5}{c}}
                 aa     & 0      & 0      & \cdots & 0  \\
                 0      & bb     & 0      & \cdots & 0  \\
                 0      & 0      & cc     & \cdots & 0  \\
                 \vdots & \vdots & \vdots & \ddots & 0  \\
                 0      & 0      & 0      & 0      & mn \\
                 \end{array}\right)\f]

◆ isSymmetric()

template<typename Type >

bool walberla::math::MatrixMxN< Type >::isSymmetric

inline

Checks if the matrix is symmetric.

Returns: true if the matrix is symmetric, false if not.

◆ nonZeros() [1/2]

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::nonZeros

inline

Returns the total number of non-zero elements in the matrix.

Returns: The number of non-zero elements in the sparse matrix.

◆ nonZeros() [2/2]

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::nonZeros ( size_t i ) const

inline

Returns the number of non-zero elements in the specified row.

Parameters

i	The index of the row.

Returns: The number of non-zero elements of row i.

◆ operator()() [1/2]

template<typename Type >

Type & walberla::math::MatrixMxN< Type >::operator()	(	size_t	i,
		size_t	j
	)

inline

2D-access to the matrix elements.

Parameters

i	Access index for the row. The index has to be in the range $[0..M-1]$ .
j	Access index for the column. The index has to be in the range $[0..N-1]$ .

Returns: Reference to the accessed value.

◆ operator()() [2/2]

template<typename Type >

const Type & walberla::math::MatrixMxN< Type >::operator()	(	size_t	i,
		size_t	j
	)		const

inline

2D-access to the matrix elements.

Parameters

i	Access index for the row. The index has to be in the range $[0..M-1]$ .
j	Access index for the column. The index has to be in the range $[0..N-1]$ .

Returns: Reference to the accessed value.

◆ operator=() [1/4]

template<typename Type >

MatrixMxN< Type > & walberla::math::MatrixMxN< Type >::operator= ( const MatrixMxN< Type > & rhs )

inline

Copy assignment operator for MatrixMxN.

Parameters

rhs	Matrix to be copied.

Returns: Reference to the assigned matrix.

The matrix is resized according to the given $M \times N$ matrix and initialized as a copy of this matrix.

◆ operator=() [2/4]

template<typename Type >

template<typename Other , size_t M, size_t N>

MatrixMxN& walberla::math::MatrixMxN< Type >::operator= ( const Other(&) rhs[M][N] )

inline

◆ operator=() [3/4]

template<typename Type >

template<typename Other , size_t M, size_t N>

MatrixMxN<Type>& walberla::math::MatrixMxN< Type >::operator= ( const Other(&) rhs[M][N] )

inline

Array assignment to all matrix elements.

Parameters

rhs	$M \times N$ dimensional array for the assignment.

Returns: Reference to the assigned matrix.

This assignment operator offers the option to directly set all elements of the matrix:

const real init[3][3] = { { 1, 2, 3 },
                          { 4, 5 },
                          { 7, 8, 9 } };
MatrixMxN<real> A;
A = init;

The matrix is resized according to the size of the array and initialized with the given values. Missing values are initialized with zero (as e.g. the value 6 in the example).

◆ operator=() [4/4]

template<typename Type >

MatrixMxN< Type > & walberla::math::MatrixMxN< Type >::operator= ( Type rhs )

inline

Homogenous assignment to all matrix elements.

Parameters

rhs	Scalar value to be assigned to all matrix elements.

Returns: Reference to the assigned matrix.

◆ operator[]() [1/2]

template<typename Type >

Type & walberla::math::MatrixMxN< Type >::operator[] ( size_t index )

inline

1D-access to the matrix elements.

Parameters

index Access index. The index has to be in the range $[0..M \cdot N-1]$ .

Returns: Reference to the accessed value.

◆ operator[]() [2/2]

template<typename Type >

const Type & walberla::math::MatrixMxN< Type >::operator[] ( size_t index ) const

inline

1D-access to the matrix elements.

Parameters

index Access index. The index has to be in the range $[0..M \cdot N-1]$ .

Returns: Reference to the accessed value.

◆ reserve()

template<typename Type >

void walberla::math::MatrixMxN< Type >::reserve ( size_t elements )

inline

Setting the minimum capacity of the matrix.

Parameters

elements The new minimum capacity of the sparse matrix.

Returns: void

This function increases the capacity of the sparse matrix to at least elements elements. The current values of the matrix elements are preserved.

◆ reset()

template<typename Type >

void walberla::math::MatrixMxN< Type >::reset

inline

Reset to the default initial values.

Returns: void

◆ resize()

template<typename Type >

void walberla::math::MatrixMxN< Type >::resize	(	size_t	m,
		size_t	n,
		bool	preserve = `true`
	)

Changing the size of the matrix.

Parameters

m	The new number of rows of the matrix.
n	The new number of columns of the matrix.
preserve	true if the old values of the matrix should be preserved, false if not.

Returns: void

This function resizes the matrix using the given size to $m \times n$ . During this operation, new dynamic memory may be allocated in case the capacity of the matrix is too small. Therefore this function potentially changes all matrix elements. In order to preserve the old matrix values, the preserve flag can be set to true. However, new matrix elements are not initialized!
The following example illustrates the resize operation of a $2 \times 4$ matrix to a $4 \times 2$ matrix. The new, uninitialized elements are marked with x:

                       \f[
                       \left(\begin{array}{*{4}{c}}
                       1 & 2 & 3 & 4 \\
                       5 & 6 & 7 & 8 \\
                       \end{array}\right)

                       \Longrightarrow

                       \left(\begin{array}{*{2}{c}}
                       1 & 2 \\
                       5 & 6 \\
                       x & x \\
                       x & x \\
                       \end{array}\right)
                       \f]

◆ rows()

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::rows

inline

Returns the current number of rows of the matrix.

Returns: The number of rows of the matrix.

◆ scale() [1/2]

template<typename Type >

template<typename Other >

MatrixMxN& walberla::math::MatrixMxN< Type >::scale ( Other scalar )

inline

◆ scale() [2/2]

template<typename Type >

template<typename Other >

MatrixMxN<Type>& walberla::math::MatrixMxN< Type >::scale ( Other scalar )

inline

Scaling of the matrix by the scalar value scalar ( $A=B*s$ ).

Parameters

scalar The scalar value for the matrix scaling.

Returns: Reference to the matrix.

◆ swap()

template<typename Type >

void walberla::math::MatrixMxN< Type >::swap ( MatrixMxN< Type > & m )

inline

Swapping the contents of two matrices.

Parameters

m	The matrix to be swapped.

Returns: void

Exceptions

no-throw guarantee.

◆ transpose()

template<typename Type >

MatrixMxN< Type > & walberla::math::MatrixMxN< Type >::transpose

inline

Transposing the matrix.

Returns: Reference to the transposed matrix.

Member Data Documentation

◆ capacity_

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::capacity_

private

The maximum capacity of the matrix.

◆ m_

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::m_

private

The current number of rows of the matrix.

◆ n_

template<typename Type >

size_t walberla::math::MatrixMxN< Type >::n_

private

The current number of columns of the matrix.

◆ v_

template<typename Type >

Type* WALBERLA_RESTRICT walberla::math::MatrixMxN< Type >::v_

private

The dynamically allocated matrix elements.

Access to the matrix elements is gained via the subscript or function call operator. The order of the elements is

$\left(\begin{array}{*{5}{c}} 0 & 1 & 2 & \cdots & N-1 \\ N & N+1 & N+2 & \cdots & 2 \cdot N-1 \\ \vdots & \vdots & \vdots & \ddots & \vdots \\ M \cdot N-N & M \cdot N-N+1 & M \cdot N-N+2 & \cdots & M \cdot N-1 \\ \end{array}\right)$

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

/builds/administration/walberla-website/walberla/src/core/math/MatrixMxN.h

Detailed Description

template<typename Type> class walberla::math::MatrixMxN< Type >

Public Types

Public Member Functions

Private Attributes

Member Typedef Documentation

◆ CompositeType

◆ ElementType

◆ ResultType

◆ This

Constructor & Destructor Documentation

◆ MatrixMxN() [1/5]

◆ MatrixMxN() [2/5]

◆ MatrixMxN() [3/5]

◆ MatrixMxN() [4/5]

◆ MatrixMxN() [5/5]

◆ ~MatrixMxN()

Member Function Documentation

◆ capacity()

◆ clear()

◆ columns()

◆ extend()

◆ isAliased()

◆ isDiagonal()

◆ isSymmetric()

◆ nonZeros() [1/2]

◆ nonZeros() [2/2]

◆ operator()() [1/2]

◆ operator()() [2/2]

◆ operator=() [1/4]

◆ operator=() [2/4]

◆ operator=() [3/4]

◆ operator=() [4/4]

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ reserve()

◆ reset()

◆ resize()

◆ rows()

◆ scale() [1/2]

◆ scale() [2/2]

◆ swap()

◆ transpose()

Member Data Documentation

◆ capacity_

◆ m_

◆ n_

◆ v_

template<typename Type>
class walberla::math::MatrixMxN< Type >