Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > Class Template Reference

The matrix class, also used for vectors and row-vectors. More...

List of all members.

Public Types

enum  { Options }
enum  { NeedsToAlign }
typedef class Eigen::Map
< Matrix, Aligned > 
AlignedMapType
typedef class Eigen::Map
< Matrix, Unaligned > 
UnalignedMapType

Public Member Functions

const Scalar & coeff (int index) const
const Scalar & coeff (int row, int col) const
Scalar & coeffRef (int index)
Scalar & coeffRef (int row, int col)
int cols () const
Scalar * data ()
const Scalar * data () const
template<typename OtherDerived >
 Matrix (const RotationBase< OtherDerived, ColsAtCompileTime > &r)
 Matrix (const Matrix &other)
template<typename OtherDerived >
 Matrix (const MatrixBase< OtherDerived > &other)
 Matrix (const Scalar *data)
 Matrix (const Scalar &x, const Scalar &y, const Scalar &z, const Scalar &w)
 Matrix (const Scalar &x, const Scalar &y, const Scalar &z)
 Matrix (const double &x, const double &y)
 Matrix (const float &x, const float &y)
 Matrix (int x, int y)
 Matrix (int dim)
 Matrix ()
template<typename OtherDerived >
Matrixoperator= (const RotationBase< OtherDerived, ColsAtCompileTime > &r)
Matrixoperator= (const Matrix &other)
template<typename OtherDerived >
Matrixoperator= (const MatrixBase< OtherDerived > &other)
template<int LoadMode>
PacketScalar packet (int index) const
template<int LoadMode>
PacketScalar packet (int row, int col) const
void resize (int size)
void resize (int rows, int cols)
int rows () const
MatrixsetConstant (int rows, int cols, const Scalar &value)
MatrixsetConstant (int size, const Scalar &value)
MatrixsetIdentity (int rows, int cols)
MatrixsetOnes (int rows, int cols)
MatrixsetOnes (int size)
MatrixsetRandom (int rows, int cols)
MatrixsetRandom (int size)
MatrixsetZero (int rows, int cols)
MatrixsetZero (int size)
int stride (void) const
void swap (Matrix &other)
template<int StoreMode>
void writePacket (int index, const PacketScalar &x)
template<int StoreMode>
void writePacket (int row, int col, const PacketScalar &x)
 ~Matrix ()

Static Public Member Functions

Map

These are convenience functions returning Map objects. The Map() static functions return unaligned Map objects, while the AlignedMap() functions return aligned Map objects and thus should be called only with 16-byte-aligned data pointers.

See also:
class Map


static UnalignedMapType Map (Scalar *data, int rows, int cols)
static const UnalignedMapType Map (const Scalar *data, int rows, int cols)
static UnalignedMapType Map (Scalar *data, int size)
static const UnalignedMapType Map (const Scalar *data, int size)
static UnalignedMapType Map (Scalar *data)
static const UnalignedMapType Map (const Scalar *data)
static AlignedMapType MapAligned (Scalar *data, int rows, int cols)
static const AlignedMapType MapAligned (const Scalar *data, int rows, int cols)
static AlignedMapType MapAligned (Scalar *data, int size)
static const AlignedMapType MapAligned (const Scalar *data, int size)
static AlignedMapType MapAligned (Scalar *data)
static const AlignedMapType MapAligned (const Scalar *data)

Protected Attributes

ei_matrix_storage< Scalar,
MaxSizeAtCompileTime,
RowsAtCompileTime,
ColsAtCompileTime, Options > 
m_storage

Detailed Description

template<typename _Scalar, int _Rows, int _Cols, int _Options, int _MaxRows, int _MaxCols>
class Eigen::Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >

The matrix class, also used for vectors and row-vectors.

The Matrix class is the work-horse for all dense (note) matrices and vectors within Eigen. Vectors are matrices with one column, and row-vectors are matrices with one row.

The Matrix class encompasses both fixed-size and dynamic-size objects (note).

The first three template parameters are required:

Parameters:
_Scalar Numeric type, i.e. float, double, int
_Rows Number of rows, or Dynamic
_Cols Number of columns, or Dynamic

The remaining template parameters are optional -- in most cases you don't have to worry about them.

Parameters:
_Options A combination of either RowMajor or ColMajor, and of either AutoAlign or DontAlign. The former controls storage order, and defaults to column-major. The latter controls alignment, which is required for vectorization. It defaults to aligning matrices except for fixed sizes that aren't a multiple of the packet size.
_MaxRows Maximum number of rows. Defaults to _Rows (note).
_MaxCols Maximum number of columns. Defaults to _Cols (note).

Eigen provides a number of typedefs covering the usual cases. Here are some examples:

See this page for a complete list of predefined Matrix and Vector typedefs.

You can access elements of vectors and matrices using normal subscripting:

 Eigen::VectorXd v(10);
 v[0] = 0.1;
 v[1] = 0.2;
 v(0) = 0.3;
 v(1) = 0.4;

 Eigen::MatrixXi m(10, 10);
 m(0, 1) = 1;
 m(0, 2) = 2;
 m(0, 3) = 3;

Some notes:

Dense versus sparse:

This Matrix class handles dense, not sparse matrices and vectors. For sparse matrices and vectors, see the Sparse module.

Dense matrices and vectors are plain usual arrays of coefficients. All the coefficients are stored, in an ordinary contiguous array. This is unlike Sparse matrices and vectors where the coefficients are stored as a list of nonzero coefficients.

Fixed-size versus dynamic-size:

Fixed-size means that the numbers of rows and columns are known are compile-time. In this case, Eigen allocates the array of coefficients as a fixed-size array, as a class member. This makes sense for very small matrices, typically up to 4x4, sometimes up to 16x16. Larger matrices should be declared as dynamic-size even if one happens to know their size at compile-time.

Dynamic-size means that the numbers of rows or columns are not necessarily known at compile-time. In this case they are runtime variables, and the array of coefficients is allocated dynamically on the heap.

Note that dense matrices, be they Fixed-size or Dynamic-size, do not expand dynamically in the sense of a std::map. If you want this behavior, see the Sparse module.

_MaxRows and _MaxCols:
In most cases, one just leaves these parameters to the default values. These parameters mean the maximum size of rows and columns that the matrix may have. They are useful in cases when the exact numbers of rows and columns are not known are compile-time, but it is known at compile-time that they cannot exceed a certain value. This happens when taking dynamic-size blocks inside fixed-size matrices: in this case _MaxRows and _MaxCols are the dimensions of the original matrix, while _Rows and _Cols are Dynamic.
See also:
MatrixBase for the majority of the API methods for matrices

Constructor & Destructor Documentation

Matrix (  )  [inline, explicit]

Default constructor.

For fixed-size matrices, does nothing.

For dynamic-size matrices, creates an empty matrix of size 0. Does not allocate any array. Such a matrix is called a null matrix. This constructor is the unique way to create null matrices: resizing a matrix to 0 is not supported.

See also:
resize(int,int)
Matrix ( int  dim  )  [inline, explicit]

Constructs a vector or row-vector with given dimension. This is only for vectors (either row-vectors or column-vectors), i.e. matrices which are known at compile-time to have either one row or one column.

Note that this is only useful for dynamic-size vectors. For fixed-size vectors, it is redundant to pass the dimension here, so it makes more sense to use the default constructor Matrix() instead.

Matrix ( int  x,
int  y 
) [inline]

This constructor has two very different behaviors, depending on the type of *this.

  • When Matrix is a fixed-size vector type of size 2, this constructor constructs an initialized vector. The parameters x, y are copied into the first and second coords of the vector respectively.
  • Otherwise, this constructor constructs an uninitialized matrix with x rows and y columns. This is useful for dynamic-size matrices. For fixed-size matrices, it is redundant to pass these parameters, so one should use the default constructor Matrix() instead.
Matrix ( const float &  x,
const float &  y 
) [inline]

constructs an initialized 2D vector with given coefficients

Matrix ( const double &  x,
const double &  y 
) [inline]

constructs an initialized 2D vector with given coefficients

Matrix ( const Scalar &  x,
const Scalar &  y,
const Scalar &  z 
) [inline]

constructs an initialized 3D vector with given coefficients

Matrix ( const Scalar &  x,
const Scalar &  y,
const Scalar &  z,
const Scalar &  w 
) [inline]

constructs an initialized 4D vector with given coefficients

Matrix ( const Scalar *  data  )  [inline, explicit]

Constructor copying an existing array of data. Only for fixed-size matrices and vectors.

Parameters:
data The array of data to copy
See also:
Matrix::Map(const Scalar *)
Matrix ( const MatrixBase< OtherDerived > &  other  )  [inline]

Constructor copying the value of the expression other

Matrix ( const Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > &  other  )  [inline]

Copy constructor

~Matrix (  )  [inline]

Destructor

Matrix ( const RotationBase< OtherDerived, ColsAtCompileTime > &  r  )  [inline, explicit]

This is defined in the Geometry module.

 #include <Eigen/Geometry> 

Constructs a Dim x Dim rotation matrix from the rotation r


Member Function Documentation

int cols ( void   )  const [inline]
Scalar* data (  )  [inline]
Returns:
a pointer to the data array of this matrix
const Scalar* data (  )  const [inline]
Returns:
a const pointer to the data array of this matrix
Matrix< _Scalar, _Rows, _Cols, _Storage, _MaxRows, _MaxCols > & operator= ( const RotationBase< OtherDerived, ColsAtCompileTime > &  r  )  [inline]

This is defined in the Geometry module.

 #include <Eigen/Geometry> 

Set a Dim x Dim rotation matrix from the rotation r

Matrix& operator= ( const Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > &  other  )  [inline]

This is a special case of the templated operator=. Its purpose is to prevent a default operator= from hiding the templated operator=.

Matrix& operator= ( const MatrixBase< OtherDerived > &  other  )  [inline]

Copies the value of the expression other into *this with automatic resizing.

*this might be resized to match the dimensions of other. If *this was a null matrix (not already initialized), it will be initialized.

Note that copying a row-vector into a vector (and conversely) is allowed. The resizing, if any, is then done in the appropriate way so that row-vectors remain row-vectors and vectors remain vectors.

Reimplemented from MatrixBase< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > >.

void resize ( int  size  )  [inline]

Resizes *this to a vector of length size

See also:
resize(int,int) for the details.
void resize ( int  rows,
int  cols 
) [inline]

Resizes *this to a rows x cols matrix.

Makes sense for dynamic-size matrices only.

If the current number of coefficients of *this exactly matches the product rows * cols, then no memory allocation is performed and the current values are left unchanged. In all other cases, including shrinking, the data is reallocated and all previous values are lost.

See also:
resize(int) for vectors.
int rows ( void   )  const [inline]
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setConstant ( int  rows,
int  cols,
const Scalar &  value 
) [inline]

Resizes to the given size, and sets all coefficients in this expression to the given value.

Parameters:
rows the new number of rows
cols the new number of columns

Example:

Output:

See also:
MatrixBase::setConstant(const Scalar&), setConstant(int,const Scalar&), class CwiseNullaryOp, MatrixBase::Constant(const Scalar&)
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setConstant ( int  size,
const Scalar &  value 
) [inline]

Resizes to the given size, and sets all coefficients in this expression to the given value.

This is only for vectors (either row-vectors or column-vectors), i.e. matrices which are known at compile-time to have either one row or one column.

Example:

Output:

See also:
MatrixBase::setConstant(const Scalar&), setConstant(int,int,const Scalar&), class CwiseNullaryOp, MatrixBase::Constant(const Scalar&)
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setIdentity ( int  rows,
int  cols 
) [inline]

Resizes to the given size, and writes the identity expression (not necessarily square) into *this.

Parameters:
rows the new number of rows
cols the new number of columns

Example:

Output:

See also:
MatrixBase::setIdentity(), class CwiseNullaryOp, MatrixBase::Identity()
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setOnes ( int  rows,
int  cols 
) [inline]

Resizes to the given size, and sets all coefficients in this expression to one.

Parameters:
rows the new number of rows
cols the new number of columns

Example:

Output:

See also:
MatrixBase::setOnes(), setOnes(int), class CwiseNullaryOp, MatrixBase::Ones()
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setOnes ( int  size  )  [inline]

Resizes to the given size, and sets all coefficients in this expression to one.

This is only for vectors (either row-vectors or column-vectors), i.e. matrices which are known at compile-time to have either one row or one column.

Example:

Output:

See also:
MatrixBase::setOnes(), setOnes(int,int), class CwiseNullaryOp, MatrixBase::Ones()
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setRandom ( int  rows,
int  cols 
) [inline]

Resizes to the given size, and sets all coefficients in this expression to random values.

Parameters:
rows the new number of rows
cols the new number of columns

Example:

Output:

See also:
MatrixBase::setRandom(), setRandom(int), class CwiseNullaryOp, MatrixBase::Random()
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setRandom ( int  size  )  [inline]

Resizes to the given size, and sets all coefficients in this expression to random values.

This is only for vectors (either row-vectors or column-vectors), i.e. matrices which are known at compile-time to have either one row or one column.

Example:

Output:

See also:
MatrixBase::setRandom(), setRandom(int,int), class CwiseNullaryOp, MatrixBase::Random()
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setZero ( int  rows,
int  cols 
) [inline]

Resizes to the given size, and sets all coefficients in this expression to zero.

Parameters:
rows the new number of rows
cols the new number of columns

Example:

Output:

See also:
MatrixBase::setZero(), setZero(int), class CwiseNullaryOp, MatrixBase::Zero()
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setZero ( int  size  )  [inline]

Resizes to the given size, and sets all coefficients in this expression to zero.

This is only for vectors (either row-vectors or column-vectors), i.e. matrices which are known at compile-time to have either one row or one column.

Example:

Output:

See also:
MatrixBase::setZero(), setZero(int,int), class CwiseNullaryOp, MatrixBase::Zero()
int stride ( void   )  const [inline]
Returns:
number of elements to skip to pass from one row (resp. column) to another for a row-major (resp. column-major) matrix. Combined with coeffRef() and the flags flags, it allows a direct access to the data of the underlying matrix.

Reimplemented from MatrixBase< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > >.

void swap ( Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > &  other  )  [inline]

Override MatrixBase::swap() since for dynamic-sized matrices of same type it is enough to swap the data pointers.


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

Generated on Mon Aug 31 17:48:41 2009 for Eigen by  doxygen 1.6.1