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:
_Scalar | Numeric type, e.g. float, double, int or std::complex<float>. User defined sclar types are supported as well (see here). |
_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.
_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:
Matrix2d
is a 2x2 square matrix of doubles (Matrix<double, 2, 2>
) Vector4f
is a vector of 4 floats (Matrix<float, 4, 1>
) RowVector3i
is a row-vector of 3 ints (Matrix<int, 1, 3>
)MatrixXf
is a dynamic-size matrix of floats (Matrix<float, Dynamic, Dynamic>
) VectorXf
is a dynamic-size vector of floats (Matrix<float, Dynamic, 1>
)Matrix2Xf
is a partially fixed-size (dynamic-size) matrix of floats (Matrix<float, 2, Dynamic>
) MatrixX3d
is a partially dynamic-size (fixed-size) matrix of double (Matrix<double, Dynamic, 3>
)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:
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 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.
#include <src/Core/Matrix.h>
Public Types | |
enum | { Options = _Options } |
enum | { NeedsToAlign } |
typedef PlainObjectBase< Matrix > | Base |
Base class typedef. | |
typedef Base::PlainObject | PlainObject |
Public Member Functions | |
EIGEN_STRONG_INLINE Matrix & | operator= (const Matrix &other) |
Assigns matrices to each other. | |
template<typename OtherDerived > | |
EIGEN_STRONG_INLINE Matrix & | operator= (const MatrixBase< OtherDerived > &other) |
template<typename OtherDerived > | |
EIGEN_STRONG_INLINE Matrix & | operator= (const EigenBase< OtherDerived > &other) |
Copies the generic expression other into *this. | |
template<typename OtherDerived > | |
EIGEN_STRONG_INLINE Matrix & | operator= (const ReturnByValue< OtherDerived > &func) |
EIGEN_STRONG_INLINE | Matrix () |
Default constructor. | |
Matrix (internal::constructor_without_unaligned_array_assert) | |
EIGEN_STRONG_INLINE | Matrix (Index dim) |
Constructs a vector or row-vector with given dimension. | |
Matrix (Index rows, Index cols) | |
Constructs an uninitialized matrix with rows rows and cols columns. | |
Matrix (const Scalar &x, const Scalar &y) | |
Constructs an initialized 2D vector with given coefficients. | |
EIGEN_STRONG_INLINE | Matrix (const Scalar &x, const Scalar &y, const Scalar &z) |
Constructs an initialized 3D vector with given coefficients. | |
EIGEN_STRONG_INLINE | Matrix (const Scalar &x, const Scalar &y, const Scalar &z, const Scalar &w) |
Constructs an initialized 4D vector with given coefficients. | |
Matrix (const Scalar *data) | |
template<typename OtherDerived > | |
EIGEN_STRONG_INLINE | Matrix (const MatrixBase< OtherDerived > &other) |
Constructor copying the value of the expression other. | |
EIGEN_STRONG_INLINE | Matrix (const Matrix &other) |
Copy constructor. | |
template<typename OtherDerived > | |
EIGEN_STRONG_INLINE | Matrix (const ReturnByValue< OtherDerived > &other) |
Copy constructor with in-place evaluation. | |
template<typename OtherDerived > | |
EIGEN_STRONG_INLINE | Matrix (const EigenBase< OtherDerived > &other) |
Copy constructor for generic expressions. | |
template<typename OtherDerived > | |
void | swap (MatrixBase< OtherDerived > const &other) |
Index | innerStride () const |
Index | outerStride () const |
template<typename OtherDerived > | |
Matrix (const RotationBase< OtherDerived, ColsAtCompileTime > &r) | |
| |
template<typename OtherDerived > | |
Matrix & | operator= (const RotationBase< OtherDerived, ColsAtCompileTime > &r) |
| |
Friends | |
struct | internal::conservative_resize_like_impl |
typedef PlainObjectBase<Matrix> Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::Base |
Base class typedef.
Reimplemented from PlainObjectBase< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > >.
Reimplemented in GeneralProduct< Lhs, Rhs, InnerProduct >.
typedef Base::PlainObject Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::PlainObject |
anonymous enum |
anonymous enum |
EIGEN_STRONG_INLINE Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::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.
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::Matrix | ( | internal::constructor_without_unaligned_array_assert | ) | [inline] |
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::Matrix | ( | Index | rows, |
Index | cols | ||
) |
Constructs an uninitialized matrix with rows rows and cols 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< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::Matrix | ( | const Scalar & | x, |
const Scalar & | y | ||
) |
Constructs an initialized 2D vector with given coefficients.
EIGEN_STRONG_INLINE Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::Matrix | ( | const MatrixBase< OtherDerived > & | other | ) | [inline] |
EIGEN_STRONG_INLINE Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::Matrix | ( | const ReturnByValue< OtherDerived > & | other | ) | [inline] |
EIGEN_STRONG_INLINE Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::Matrix | ( | const EigenBase< OtherDerived > & | other | ) | [inline] |
Copy constructor for generic expressions.
Matrix< _Scalar, _Rows, _Cols, _Storage, _MaxRows, _MaxCols >::Matrix | ( | const RotationBase< OtherDerived, ColsAtCompileTime > & | r | ) | [explicit] |
Constructs a Dim x Dim rotation matrix from the rotation r
Definition at line 154 of file RotationBase.h.
References EIGEN_STATIC_ASSERT_MATRIX_SPECIFIC_SIZE, and RotationBase< Derived, _Dim >::toRotationMatrix().
Matrix< _Scalar, _Rows, _Cols, _Storage, _MaxRows, _MaxCols > & Matrix< _Scalar, _Rows, _Cols, _Storage, _MaxRows, _MaxCols >::operator= | ( | const RotationBase< OtherDerived, ColsAtCompileTime > & | r | ) |
Set a Dim x Dim rotation matrix from the rotation r
Definition at line 168 of file RotationBase.h.
References EIGEN_STATIC_ASSERT_MATRIX_SPECIFIC_SIZE, and RotationBase< Derived, _Dim >::toRotationMatrix().
EIGEN_STRONG_INLINE Matrix& Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::operator= | ( | const MatrixBase< OtherDerived > & | other | ) | [inline] |
EIGEN_STRONG_INLINE Matrix& Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::operator= | ( | const EigenBase< OtherDerived > & | other | ) | [inline] |
Copies the generic expression other into *this.
The expression must provide a (templated) evalTo(Derived& dst) const function which does the actual job. In practice, this allows any user to write its own special matrix without having to modify MatrixBase
Reimplemented from PlainObjectBase< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > >.
EIGEN_STRONG_INLINE Matrix& Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::operator= | ( | const ReturnByValue< OtherDerived > & | func | ) | [inline] |
Reimplemented from PlainObjectBase< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > >.
Index Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::outerStride | ( | ) | const [inline] |
Definition at line 330 of file Matrix.h.
Referenced by internal::product_triangular_matrix_matrix< Scalar, Index, Mode, false, LhsStorageOrder, ConjugateLhs, RhsStorageOrder, ConjugateRhs, ColMajor >::run(), and internal::product_triangular_matrix_matrix< Scalar, Index, Mode, true, LhsStorageOrder, ConjugateLhs, RhsStorageOrder, ConjugateRhs, ColMajor >::run().
void Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >::swap | ( | MatrixBase< OtherDerived > const & | other | ) | [inline] |
Definition at line 326 of file Matrix.h.
Referenced by FullPivHouseholderQR< _MatrixType >::matrixQ().
friend struct internal::conservative_resize_like_impl [friend] |
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