DenseBase< Derived > Class Template Reference

Base class for all dense matrices, vectors, and arrays. More...

#include <DenseBase.h>

+ Inheritance diagram for DenseBase< Derived >:

Public Types

enum  {
  RowsAtCompileTime ,
  ColsAtCompileTime ,
  SizeAtCompileTime ,
  MaxRowsAtCompileTime ,
  MaxColsAtCompileTime ,
  MaxSizeAtCompileTime ,
  IsVectorAtCompileTime ,
  Flags ,
  IsRowMajor ,
  InnerSizeAtCompileTime ,
  CoeffReadCost ,
  InnerStrideAtCompileTime ,
  OuterStrideAtCompileTime
}
 
typedef internal::traits< Derived >::Index Index
 The type of indices.
 

Public Member Functions

bool all (void) const
 
bool any (void) const
 
template<int BlockRows, int BlockCols>
Block< Derived, BlockRows, BlockCols > block (Index startRow, Index startCol)
 
template<int BlockRows, int BlockCols>
const Block< const Derived, BlockRows, BlockCols > block (Index startRow, Index startCol) const
 
Block< Derived > block (Index startRow, Index startCol, Index blockRows, Index blockCols)
 
const Block< const Derived > block (Index startRow, Index startCol, Index blockRows, Index blockCols) const
 
template<int CRows, int CCols>
Block< Derived, CRows, CCols > bottomLeftCorner ()
 
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > bottomLeftCorner () const
 
Block< Derived > bottomLeftCorner (Index cRows, Index cCols)
 
const Block< const Derived > bottomLeftCorner (Index cRows, Index cCols) const
 
template<int CRows, int CCols>
Block< Derived, CRows, CCols > bottomRightCorner ()
 
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > bottomRightCorner () const
 
Block< Derived > bottomRightCorner (Index cRows, Index cCols)
 
const Block< const Derived > bottomRightCorner (Index cRows, Index cCols) const
 
template<int N>
NRowsBlockXpr< N >::Type bottomRows ()
 
template<int N>
ConstNRowsBlockXpr< N >::Type bottomRows () const
 
RowsBlockXpr bottomRows (Index n)
 
ConstRowsBlockXpr bottomRows (Index n) const
 
ColXpr col (Index i)
 
ConstColXpr col (Index i) const
 
ColwiseReturnType colwise ()
 
ConstColwiseReturnType colwise () const
 
Index count () const
 
EvalReturnType eval () const
 
void fill (const Scalar &value)
 
template<unsigned int Added, unsigned int Removed>
const Flagged< Derived, Added, Removed > flagged () const
 
const WithFormat< Derived > format (const IOFormat &fmt) const
 
template<int Size>
DenseBase< Derived >::template FixedSegmentReturnType< Size >::Type head ()
 
template<int Size>
DenseBase< Derived >::template ConstFixedSegmentReturnType< Size >::Type head () const
 
SegmentReturnType head (Index size)
 
DenseBase::ConstSegmentReturnType head (Index size) const
 
Index innerSize () const
 
template<typename OtherDerived>
bool isApprox (const DenseBase< OtherDerived > &other, RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
 
bool isApproxToConstant (const Scalar &value, RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
 
bool isConstant (const Scalar &value, RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
 
template<typename OtherDerived>
bool isMuchSmallerThan (const DenseBase< OtherDerived > &other, RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
 
template<typename Derived>
bool isMuchSmallerThan (const typename NumTraits< Scalar >::Real &other, RealScalar prec) const
 
bool isOnes (RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
 
bool isZero (RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
 
template<int N>
NColsBlockXpr< N >::Type leftCols ()
 
template<int N>
ConstNColsBlockXpr< N >::Type leftCols () const
 
ColsBlockXpr leftCols (Index n)
 
ConstColsBlockXpr leftCols (Index n) const
 
internal::traits< Derived >::Scalar maxCoeff () const
 
template<typename IndexType>
internal::traits< Derived >::Scalar maxCoeff (IndexType *index) const
 
template<typename IndexType>
internal::traits< Derived >::Scalar maxCoeff (IndexType *row, IndexType *col) const
 
Scalar mean () const
 
template<int N>
NColsBlockXpr< N >::Type middleCols (Index startCol)
 
template<int N>
ConstNColsBlockXpr< N >::Type middleCols (Index startCol) const
 
ColsBlockXpr middleCols (Index startCol, Index numCols)
 
ConstColsBlockXpr middleCols (Index startCol, Index numCols) const
 
template<int N>
NRowsBlockXpr< N >::Type middleRows (Index startRow)
 
template<int N>
ConstNRowsBlockXpr< N >::Type middleRows (Index startRow) const
 
RowsBlockXpr middleRows (Index startRow, Index numRows)
 
ConstRowsBlockXpr middleRows (Index startRow, Index numRows) const
 
internal::traits< Derived >::Scalar minCoeff () const
 
template<typename IndexType>
internal::traits< Derived >::Scalar minCoeff (IndexType *index) const
 
template<typename IndexType>
internal::traits< Derived >::Scalar minCoeff (IndexType *row, IndexType *col) const
 
const NestByValue< Derived > nestByValue () const
 
Index nonZeros () const
 
template<typename OtherDerived>
CommaInitializer< Derived > operator<< (const DenseBase< OtherDerived > &other)
 
CommaInitializer< Derived > operator<< (const Scalar &s)
 
Derived & operator= (const DenseBase &other)
 
template<typename OtherDerived>
Derived & operator= (const DenseBase< OtherDerived > &other)
 
template<typename OtherDerived>
Derived & operator= (const EigenBase< OtherDerived > &other)
 Copies the generic expression other into *this.
 
Index outerSize () const
 
Scalar prod () const
 
template<typename Func>
internal::result_of< Func(typenameinternal::traits< Derived >::Scalar)>::type redux (const Func &func) const
 
template<int RowFactor, int ColFactor>
const Replicate< Derived, RowFactor, ColFactor > replicate () const
 
const Replicate< Derived, Dynamic, Dynamic > replicate (Index rowFacor, Index colFactor) const
 
void resize (Index rows, Index cols)
 
void resize (Index size)
 
ReverseReturnType reverse ()
 
ConstReverseReturnType reverse () const
 
void reverseInPlace ()
 
template<int N>
NColsBlockXpr< N >::Type rightCols ()
 
template<int N>
ConstNColsBlockXpr< N >::Type rightCols () const
 
ColsBlockXpr rightCols (Index n)
 
ConstColsBlockXpr rightCols (Index n) const
 
RowXpr row (Index i)
 
ConstRowXpr row (Index i) const
 
RowwiseReturnType rowwise ()
 
ConstRowwiseReturnType rowwise () const
 
template<int Size>
DenseBase< Derived >::template FixedSegmentReturnType< Size >::Type segment (Index start)
 
template<int Size>
DenseBase< Derived >::template ConstFixedSegmentReturnType< Size >::Type segment (Index start) const
 
SegmentReturnType segment (Index start, Index size)
 
DenseBase::ConstSegmentReturnType segment (Index start, Index size) const
 
template<typename ThenDerived, typename ElseDerived>
const Select< Derived, ThenDerived, ElseDerived > select (const DenseBase< ThenDerived > &thenMatrix, const DenseBase< ElseDerived > &elseMatrix) const
 
template<typename ThenDerived>
const Select< Derived, ThenDerived, typename ThenDerived::ConstantReturnType > select (const DenseBase< ThenDerived > &thenMatrix, typename ThenDerived::Scalar elseScalar) const
 
template<typename ElseDerived>
const Select< Derived, typename ElseDerived::ConstantReturnType, ElseDerived > select (typename ElseDerived::Scalar thenScalar, const DenseBase< ElseDerived > &elseMatrix) const
 
Derived & setConstant (const Scalar &value)
 
Derived & setLinSpaced (const Scalar &low, const Scalar &high)
 Sets a linearly space vector.
 
Derived & setLinSpaced (Index size, const Scalar &low, const Scalar &high)
 Sets a linearly space vector.
 
Derived & setOnes ()
 
Derived & setRandom ()
 
Derived & setZero ()
 
Scalar sum () const
 
template<typename OtherDerived>
void swap (const DenseBase< OtherDerived > &other, int=OtherDerived::ThisConstantIsPrivateInPlainObjectBase)
 
template<typename OtherDerived>
void swap (PlainObjectBase< OtherDerived > &other)
 
template<int Size>
DenseBase< Derived >::template FixedSegmentReturnType< Size >::Type tail ()
 
template<int Size>
DenseBase< Derived >::template ConstFixedSegmentReturnType< Size >::Type tail () const
 
SegmentReturnType tail (Index size)
 
DenseBase::ConstSegmentReturnType tail (Index size) const
 
template<int CRows, int CCols>
Block< Derived, CRows, CCols > topLeftCorner ()
 
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > topLeftCorner () const
 
Block< Derived > topLeftCorner (Index cRows, Index cCols)
 
const Block< const Derived > topLeftCorner (Index cRows, Index cCols) const
 
template<int CRows, int CCols>
Block< Derived, CRows, CCols > topRightCorner ()
 
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > topRightCorner () const
 
Block< Derived > topRightCorner (Index cRows, Index cCols)
 
const Block< const Derived > topRightCorner (Index cRows, Index cCols) const
 
template<int N>
NRowsBlockXpr< N >::Type topRows ()
 
template<int N>
ConstNRowsBlockXpr< N >::Type topRows () const
 
RowsBlockXpr topRows (Index n)
 
ConstRowsBlockXpr topRows (Index n) const
 
Eigen::Transpose< Derived > transpose ()
 
ConstTransposeReturnType transpose () const
 
void transposeInPlace ()
 
CoeffReturnType value () const
 
template<typename Visitor>
void visit (Visitor &func) const
 

Static Public Member Functions

static const ConstantReturnType Constant (const Scalar &value)
 
static const ConstantReturnType Constant (Index rows, Index cols, const Scalar &value)
 
static const ConstantReturnType Constant (Index size, const Scalar &value)
 
static const RandomAccessLinSpacedReturnType LinSpaced (const Scalar &low, const Scalar &high)
 Sets a linearly space vector.
 
static const RandomAccessLinSpacedReturnType LinSpaced (Index size, const Scalar &low, const Scalar &high)
 Sets a linearly space vector.
 
static const SequentialLinSpacedReturnType LinSpaced (Sequential_t, const Scalar &low, const Scalar &high)
 Sets a linearly space vector.
 
static const SequentialLinSpacedReturnType LinSpaced (Sequential_t, Index size, const Scalar &low, const Scalar &high)
 Sets a linearly space vector.
 
template<typename CustomNullaryOp>
static const CwiseNullaryOp< CustomNullaryOp, Derived > NullaryExpr (const CustomNullaryOp &func)
 
template<typename CustomNullaryOp>
static const CwiseNullaryOp< CustomNullaryOp, Derived > NullaryExpr (Index rows, Index cols, const CustomNullaryOp &func)
 
template<typename CustomNullaryOp>
static const CwiseNullaryOp< CustomNullaryOp, Derived > NullaryExpr (Index size, const CustomNullaryOp &func)
 
static const ConstantReturnType Ones ()
 
static const ConstantReturnType Ones (Index rows, Index cols)
 
static const ConstantReturnType Ones (Index size)
 
static const CwiseNullaryOp< internal::scalar_random_op< Scalar >, Derived > Random ()
 
static const CwiseNullaryOp< internal::scalar_random_op< Scalar >, Derived > Random (Index rows, Index cols)
 
static const CwiseNullaryOp< internal::scalar_random_op< Scalar >, Derived > Random (Index size)
 
static const ConstantReturnType Zero ()
 
static const ConstantReturnType Zero (Index rows, Index cols)
 
static const ConstantReturnType Zero (Index size)
 

Protected Member Functions

 DenseBase ()
 

Related Symbols

(Note that these are not member symbols.)

template<typename Derived>
std::ostream & operator<< (std::ostream &s, const DenseBase< Derived > &m)
 

Detailed Description

template<typename Derived>
class Eigen::DenseBase< Derived >

Base class for all dense matrices, vectors, and arrays.

This class is the base that is inherited by all dense objects (matrix, vector, arrays, and related expression types). The common Eigen API for dense objects is contained in this class.

Template Parameters
Derivedis the derived type, e.g., a matrix type or an expression.

This class can be extended with the help of the plugin mechanism described on the page Customizing/Extending Eigen by defining the preprocessor symbol EIGEN_DENSEBASE_PLUGIN.

See also
The class hierarchy

Member Typedef Documentation

◆ Index

template<typename Derived>
typedef internal::traits<Derived>::Index Index

The type of indices.

To change this, #define the preprocessor symbol EIGEN_DEFAULT_DENSE_INDEX_TYPE.

See also
Preprocessor directives.

Member Enumeration Documentation

◆ anonymous enum

template<typename Derived>
anonymous enum
Enumerator
RowsAtCompileTime 

The number of rows at compile-time. This is just a copy of the value provided by the Derived type. If a value is not known at compile-time, it is set to the Dynamic constant.

See also
MatrixBase::rows(), MatrixBase::cols(), ColsAtCompileTime, SizeAtCompileTime
ColsAtCompileTime 

The number of columns at compile-time. This is just a copy of the value provided by the Derived type. If a value is not known at compile-time, it is set to the Dynamic constant.

See also
MatrixBase::rows(), MatrixBase::cols(), RowsAtCompileTime, SizeAtCompileTime
SizeAtCompileTime 

This is equal to the number of coefficients, i.e. the number of rows times the number of columns, or to Dynamic if this is not known at compile-time.

See also
RowsAtCompileTime, ColsAtCompileTime
MaxRowsAtCompileTime 

This value is equal to the maximum possible number of rows that this expression might have. If this expression might have an arbitrarily high number of rows, this value is set to Dynamic.

This value is useful to know when evaluating an expression, in order to determine whether it is possible to avoid doing a dynamic memory allocation.

See also
RowsAtCompileTime, MaxColsAtCompileTime, MaxSizeAtCompileTime
MaxColsAtCompileTime 

This value is equal to the maximum possible number of columns that this expression might have. If this expression might have an arbitrarily high number of columns, this value is set to Dynamic.

This value is useful to know when evaluating an expression, in order to determine whether it is possible to avoid doing a dynamic memory allocation.

See also
ColsAtCompileTime, MaxRowsAtCompileTime, MaxSizeAtCompileTime
MaxSizeAtCompileTime 

This value is equal to the maximum possible number of coefficients that this expression might have. If this expression might have an arbitrarily high number of coefficients, this value is set to Dynamic.

This value is useful to know when evaluating an expression, in order to determine whether it is possible to avoid doing a dynamic memory allocation.

See also
SizeAtCompileTime, MaxRowsAtCompileTime, MaxColsAtCompileTime
IsVectorAtCompileTime 

This is set to true if either the number of rows or the number of columns is known at compile-time to be equal to 1. Indeed, in that case, we are dealing with a column-vector (if there is only one column) or with a row-vector (if there is only one row).

Flags 

This stores expression Flags flags which may or may not be inherited by new expressions constructed from this one. See the list of flags.

IsRowMajor 

True if this expression has row-major storage order.

CoeffReadCost 

This is a rough measure of how expensive it is to read one coefficient from this expression.

Constructor & Destructor Documentation

◆ DenseBase()

Member Function Documentation

◆ all()

template<typename Derived>
bool all ( void ) const
inline
Returns
true if all coefficients are true

Example:

Vector3f boxMin(Vector3f::Zero()), boxMax(Vector3f::Ones());
Vector3f p0 = Vector3f::Random(), p1 = Vector3f::Random().cwiseAbs();
// let's check if p0 and p1 are inside the axis aligned box defined by the corners boxMin,boxMax:
cout << "Is (" << p0.transpose() << ") inside the box: "
<< ((boxMin.array()<p0.array()).all() && (boxMax.array()>p0.array()).all()) << endl;
cout << "Is (" << p1.transpose() << ") inside the box: "
<< ((boxMin.array()<p1.array()).all() && (boxMax.array()>p1.array()).all()) << endl;
Eigen::Transpose< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > transpose()
Definition Transpose.h:199
static const ConstantReturnType Zero(Index rows, Index cols)
Definition CwiseNullaryOp.h:428
static const CwiseNullaryOp< internal::scalar_random_op< Scalar >, Matrix< float, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > Random(Index rows, Index cols)
Definition Random.h:49
static const ConstantReturnType Ones(Index rows, Index cols)
Definition CwiseNullaryOp.h:557
ArrayWrapper< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > array()
Definition MatrixBase.h:308

Output:

Is (  0.68 -0.211  0.566) inside the box: 0
Is (0.597 0.823 0.605) inside the box: 1
See also
any(), Cwise::operator<()

References CoeffReadCost, and SizeAtCompileTime.

Referenced by rightCols().

◆ any()

template<typename Derived>
bool any ( void ) const
inline
Returns
true if at least one coefficient is true
See also
all()

References CoeffReadCost, and SizeAtCompileTime.

Referenced by rightCols().

◆ block() [1/4]

template<typename Derived>
template<int BlockRows, int BlockCols>
Block< Derived, BlockRows, BlockCols > block ( Index startRow,
Index startCol )
inline
Returns
a fixed-size expression of a block in *this.

The template parameters BlockRows and BlockCols are the number of rows and columns in the block.

Parameters
startRowthe first row in the block
startColthe first column in the block

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.block<2,2>(1,1):" << endl << m.block<2,2>(1,1) << endl;
m.block<2,2>(1,1).setZero();
cout << "Now the matrix m is:" << endl << m << endl;
Block< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > block(Index startRow, Index startCol, Index blockRows, Index blockCols)
Definition DenseBase.h:55
Derived & setZero()
Definition CwiseNullaryOp.h:499

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.block<2,2>(1,1):
-6 1
-3 0
Now the matrix m is:
 7  9 -5 -3
-2  0  0  0
 6  0  0  9
 6  6  3  9
Note
since block is a templated member, the keyword template has to be used if the matrix type is also a template parameter:
m.template block<3,3>(1,1);
See also
class Block, block(Index,Index,Index,Index)

◆ block() [2/4]

template<typename Derived>
template<int BlockRows, int BlockCols>
const Block< const Derived, BlockRows, BlockCols > block ( Index startRow,
Index startCol ) const
inline

This is the const version of block<>(Index, Index).

◆ block() [3/4]

template<typename Derived>
Block< Derived > block ( Index startRow,
Index startCol,
Index blockRows,
Index blockCols )
inline
Returns
a dynamic-size expression of a block in *this.
Parameters
startRowthe first row in the block
startColthe first column in the block
blockRowsthe number of rows in the block
blockColsthe number of columns in the block

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.block(1, 1, 2, 2):" << endl << m.block(1, 1, 2, 2) << endl;
m.block(1, 1, 2, 2).setZero();
cout << "Now the matrix m is:" << endl << m << endl;

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.block(1, 1, 2, 2):
-6 1
-3 0
Now the matrix m is:
 7  9 -5 -3
-2  0  0  0
 6  0  0  9
 6  6  3  9
Note
Even though the returned expression has dynamic size, in the case when it is applied to a fixed-size matrix, it inherits a fixed maximal size, which means that evaluating it does not cause a dynamic memory allocation.
See also
class Block, block(Index,Index)

◆ block() [4/4]

template<typename Derived>
const Block< const Derived > block ( Index startRow,
Index startCol,
Index blockRows,
Index blockCols ) const
inline

This is the const version of block(Index,Index,Index,Index).

◆ bottomLeftCorner() [1/4]

template<typename Derived>
template<int CRows, int CCols>
Block< Derived, CRows, CCols > bottomLeftCorner ( )
inline
Returns
an expression of a fixed-size bottom-left corner of *this.

The template parameters CRows and CCols are the number of rows and columns in the corner.

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.bottomLeftCorner<2,2>():" << endl;
cout << m.bottomLeftCorner<2,2>() << endl;
cout << "Now the matrix m is:" << endl << m << endl;
Block< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > bottomLeftCorner(Index cRows, Index cCols)
Definition DenseBase.h:215

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.bottomLeftCorner<2,2>():
 6 -3
 6  6
Now the matrix m is:
 7  9 -5 -3
-2 -6  1  0
 0  0  0  9
 0  0  3  9
See also
class Block, block(Index,Index,Index,Index)

References DenseBase().

◆ bottomLeftCorner() [2/4]

template<typename Derived>
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > bottomLeftCorner ( ) const
inline

This is the const version of bottomLeftCorner<int, int>().

References DenseBase().

◆ bottomLeftCorner() [3/4]

template<typename Derived>
Block< Derived > bottomLeftCorner ( Index cRows,
Index cCols )
inline
Returns
a dynamic-size expression of a bottom-left corner of *this.
Parameters
cRowsthe number of rows in the corner
cColsthe number of columns in the corner

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.bottomLeftCorner(2, 2):" << endl;
cout << m.bottomLeftCorner(2, 2) << endl;
m.bottomLeftCorner(2, 2).setZero();
cout << "Now the matrix m is:" << endl << m << endl;

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.bottomLeftCorner(2, 2):
 6 -3
 6  6
Now the matrix m is:
 7  9 -5 -3
-2 -6  1  0
 0  0  0  9
 0  0  3  9
See also
class Block, block(Index,Index,Index,Index)

◆ bottomLeftCorner() [4/4]

template<typename Derived>
const Block< const Derived > bottomLeftCorner ( Index cRows,
Index cCols ) const
inline

This is the const version of bottomLeftCorner(Index, Index).

◆ bottomRightCorner() [1/4]

template<typename Derived>
template<int CRows, int CCols>
Block< Derived, CRows, CCols > bottomRightCorner ( )
inline
Returns
an expression of a fixed-size bottom-right corner of *this.

The template parameters CRows and CCols are the number of rows and columns in the corner.

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.bottomRightCorner<2,2>():" << endl;
cout << m.bottomRightCorner<2,2>() << endl;
cout << "Now the matrix m is:" << endl << m << endl;
Block< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > bottomRightCorner(Index cRows, Index cCols)
Definition DenseBase.h:170

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.bottomRightCorner<2,2>():
0 9
3 9
Now the matrix m is:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  0
 6  6  0  0
See also
class Block, block(Index,Index,Index,Index)

◆ bottomRightCorner() [2/4]

template<typename Derived>
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > bottomRightCorner ( ) const
inline

This is the const version of bottomRightCorner<int, int>().

References IsRowMajor, and IsVectorAtCompileTime.

◆ bottomRightCorner() [3/4]

template<typename Derived>
Block< Derived > bottomRightCorner ( Index cRows,
Index cCols )
inline
Returns
a dynamic-size expression of a bottom-right corner of *this.
Parameters
cRowsthe number of rows in the corner
cColsthe number of columns in the corner

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.bottomRightCorner(2, 2):" << endl;
cout << m.bottomRightCorner(2, 2) << endl;
m.bottomRightCorner(2, 2).setZero();
cout << "Now the matrix m is:" << endl << m << endl;

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.bottomRightCorner(2, 2):
0 9
3 9
Now the matrix m is:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  0
 6  6  0  0
See also
class Block, block(Index,Index,Index,Index)

◆ bottomRightCorner() [4/4]

template<typename Derived>
const Block< const Derived > bottomRightCorner ( Index cRows,
Index cCols ) const
inline

This is the const version of bottomRightCorner(Index, Index).

◆ bottomRows() [1/4]

template<typename Derived>
template<int N>
NRowsBlockXpr< N >::Type bottomRows ( )
inline
Returns
a block consisting of the bottom rows of *this.
Template Parameters
Nthe number of rows in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.bottomRows<2>():" << endl;
cout << a.bottomRows<2>() << endl;
a.bottomRows<2>().setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.bottomRows<2>():
 6 -3  0  9
 6  6  3  9
Now the array a is:
 7  9 -5 -3
-2 -6  1  0
 0  0  0  0
 0  0  0  0
See also
class Block, block(Index,Index,Index,Index)

◆ bottomRows() [2/4]

template<typename Derived>
template<int N>
ConstNRowsBlockXpr< N >::Type bottomRows ( ) const
inline

This is the const version of bottomRows<int>().

References value().

◆ bottomRows() [3/4]

template<typename Derived>
RowsBlockXpr bottomRows ( Index n)
inline
Returns
a block consisting of the bottom rows of *this.
Parameters
nthe number of rows in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.bottomRows(2):" << endl;
cout << a.bottomRows(2) << endl;
a.bottomRows(2).setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.bottomRows(2):
 6 -3  0  9
 6  6  3  9
Now the array a is:
 7  9 -5 -3
-2 -6  1  0
 0  0  0  0
 0  0  0  0
See also
class Block, block(Index,Index,Index,Index)

References tail().

◆ bottomRows() [4/4]

template<typename Derived>
ConstRowsBlockXpr bottomRows ( Index n) const
inline

This is the const version of bottomRows(Index).

References value().

◆ col() [1/2]

template<typename Derived>
ColXpr col ( Index i)
inline
Returns
an expression of the i-th column of *this. Note that the numbering starts at 0.

Example:

Matrix3d m = Matrix3d::Identity();
m.col(1) = Vector3d(4,5,6);
cout << m << endl;
static const IdentityReturnType Identity()
Definition CwiseNullaryOp.h:700

Output:

1 4 0
0 5 0
0 6 1
See also
row(), class Block

Referenced by MatrixBase< Derived >::applyHouseholderOnTheRight(), MatrixBase< Derived >::applyOnTheRight(), VectorwiseOp< ExpressionType, Direction >::cross(), leftCols(), maxCoeff(), and minCoeff().

◆ col() [2/2]

template<typename Derived>
ConstColXpr col ( Index i) const
inline

This is the const version of col().

◆ colwise() [1/2]

template<typename Derived>
DenseBase< Derived >::ColwiseReturnType colwise ( )
inline
Returns
a writable VectorwiseOp wrapper of *this providing additional partial reduction operations
See also
rowwise(), class VectorwiseOp, Tutorial page 7 - Reductions, visitors and broadcasting

References colwise().

◆ colwise() [2/2]

template<typename Derived>
const DenseBase< Derived >::ConstColwiseReturnType colwise ( ) const
inline
Returns
a VectorwiseOp wrapper of *this providing additional partial reduction operations

Example:

Matrix3d m = Matrix3d::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is the sum of each column:" << endl << m.colwise().sum() << endl;
cout << "Here is the maximum absolute value of each column:"
<< endl << m.cwiseAbs().colwise().maxCoeff() << endl;
ConstColwiseReturnType colwise() const
Definition VectorwiseOp.h:555
const CwiseUnaryOp< internal::scalar_abs_op< Scalar >, const Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > cwiseAbs() const
Definition MatrixBase.h:22
const ReturnType< internal::member_sum >::Type sum() const
Definition VectorwiseOp.h:330

Output:

Here is the matrix m:
  0.68  0.597  -0.33
-0.211  0.823  0.536
 0.566 -0.605 -0.444
Here is the sum of each column:
  1.04  0.815 -0.238
Here is the maximum absolute value of each column:
 0.68 0.823 0.536
See also
rowwise(), class VectorwiseOp, Tutorial page 7 - Reductions, visitors and broadcasting

References colwise().

Referenced by colwise(), colwise(), rightCols(), and Eigen::umeyama().

◆ Constant() [1/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Constant ( const Scalar & value)
inlinestatic
Returns
an expression of a constant matrix of value value

This variant is only for fixed-size DenseBase types. For dynamic-size types, you need to use the variants taking size arguments.

The template parameter CustomNullaryOp is the type of the functor.

See also
class CwiseNullaryOp

References ColsAtCompileTime, NullaryExpr(), RowsAtCompileTime, and value().

◆ Constant() [2/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Constant ( Index rows,
Index cols,
const Scalar & value )
inlinestatic
Returns
an expression of a constant matrix of value value

The parameters rows and cols are the number of rows and of columns of the returned matrix. Must be compatible with this DenseBase type.

This variant is meant to be used for dynamic-size matrix types. For fixed-size types, it is redundant to pass rows and cols as arguments, so Zero() should be used instead.

The template parameter CustomNullaryOp is the type of the functor.

See also
class CwiseNullaryOp

References NullaryExpr(), and value().

Referenced by Ones(), Ones(), Ones(), Zero(), Zero(), and Zero().

◆ Constant() [3/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Constant ( Index size,
const Scalar & value )
inlinestatic
Returns
an expression of a constant matrix of value value

The parameter size is the size of the returned vector. Must be compatible with this DenseBase type.

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.

This variant is meant to be used for dynamic-size vector types. For fixed-size types, it is redundant to pass size as argument, so Zero() should be used instead.

The template parameter CustomNullaryOp is the type of the functor.

See also
class CwiseNullaryOp

References NullaryExpr(), and value().

◆ count()

template<typename Derived>
DenseBase< Derived >::Index count ( ) const
inline
Returns
the number of coefficients which evaluate to true
See also
all(), any()

Referenced by rightCols().

◆ eval()

template<typename Derived>
EvalReturnType eval ( ) const
inline
Returns
the matrix or vector obtained by evaluating this expression.

Notice that in the case of a plain matrix or vector (not an expression) this function just returns a const reference, in order to avoid a useless copy.

Referenced by MatrixBase< Derived >::colPivHouseholderQr(), MatrixBase< Derived >::fullPivHouseholderQr(), MatrixBase< Derived >::fullPivLu(), MatrixBase< Derived >::householderQr(), MatrixBase< Derived >::lu(), and MatrixBase< Derived >::partialPivLu().

◆ fill()

template<typename Derived>
void fill ( const Scalar & value)
inline

Alias for setConstant(): sets all coefficients in this expression to value.

See also
setConstant(), Constant(), class CwiseNullaryOp

References setConstant(), and value().

◆ flagged()

template<typename Derived>
template<unsigned int Added, unsigned int Removed>
const Flagged< Derived, Added, Removed > flagged ( ) const
inline
Returns
an expression of *this with added and removed flags

This is mostly for internal use.

See also
class Flagged

◆ format()

template<typename Derived>
const WithFormat< Derived > format ( const IOFormat & fmt) const
inline
Returns
a WithFormat proxy object allowing to print a matrix the with given format fmt.

See class IOFormat for some examples.

See also
class IOFormat, class WithFormat

◆ head() [1/4]

template<typename Derived>
template<int Size>
DenseBase< Derived >::template FixedSegmentReturnType< Size >::Type head ( )
inline
Returns
a fixed-size expression of the first coefficients of *this.

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.

The template parameter Size is the number of coefficients in the block

Example:

RowVector4i v = RowVector4i::Random();
cout << "Here is the vector v:" << endl << v << endl;
cout << "Here is v.head(2):" << endl << v.head<2>() << endl;
v.head<2>().setZero();
cout << "Now the vector v is:" << endl << v << endl;
SegmentReturnType head(Index size)
Definition VectorBlock.h:143

Output:

Here is the vector v:
 7 -2  6  6
Here is v.head(2):
 7 -2
Now the vector v is:
0 0 6 6
See also
class Block

◆ head() [2/4]

template<typename Derived>
template<int Size>
DenseBase< Derived >::template ConstFixedSegmentReturnType< Size >::Type head ( ) const
inline

This is the const version of head<int>().

◆ head() [3/4]

template<typename Derived>
DenseBase< Derived >::SegmentReturnType head ( Index size)
inline
Returns
a dynamic-size expression of the first coefficients of *this.

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.

Parameters
sizethe number of coefficients in the block

Example:

RowVector4i v = RowVector4i::Random();
cout << "Here is the vector v:" << endl << v << endl;
cout << "Here is v.head(2):" << endl << v.head(2) << endl;
v.head(2).setZero();
cout << "Now the vector v is:" << endl << v << endl;

Output:

Here is the vector v:
 7 -2  6  6
Here is v.head(2):
 7 -2
Now the vector v is:
0 0 6 6
Note
Even though the returned expression has dynamic size, in the case when it is applied to a fixed-size vector, it inherits a fixed maximal size, which means that evaluating it does not cause a dynamic memory allocation.
See also
class Block, block(Index,Index)

References head().

Referenced by head(), head(), DenseBase< ArrayWrapper< ExpressionType > >::head(), DenseBase< ArrayWrapper< ExpressionType > >::head(), and MatrixBase< Derived >::stableNorm().

◆ head() [4/4]

template<typename Derived>
DenseBase< Derived >::ConstSegmentReturnType head ( Index size) const
inline

This is the const version of head(Index).

References head().

◆ innerSize()

template<typename Derived>
Index innerSize ( ) const
inline
Returns
the inner size.
Note
For a vector, this is just the size. For a matrix (non-vector), this is the minor dimension with respect to the storage order, i.e., the number of rows for a column-major matrix, and the number of columns for a row-major matrix.

◆ isApprox()

template<typename Derived>
template<typename OtherDerived>
bool isApprox ( const DenseBase< OtherDerived > & other,
RealScalar prec = NumTraits<Scalar>::dummy_precision() ) const
Returns
true if *this is approximately equal to other, within the precision determined by prec.
Note
The fuzzy compares are done multiplicatively. Two vectors $ v $ and $ w $ are considered to be approximately equal within precision $ p $ if

\[ \Vert v - w \Vert \leqslant p\,\min(\Vert v\Vert, \Vert w\Vert). \]

For matrices, the comparison is done using the Hilbert-Schmidt norm (aka Frobenius norm L2 norm).
Because of the multiplicativeness of this comparison, one can't use this function to check whether *this is approximately equal to the zero matrix or vector. Indeed, isApprox(zero) returns false unless *this itself is exactly the zero matrix or vector. If you want to test whether *this is zero, use internal::isMuchSmallerThan(const RealScalar&, RealScalar) instead.
See also
internal::isMuchSmallerThan(const RealScalar&, RealScalar) const

References DenseBase().

◆ isApproxToConstant()

template<typename Derived>
bool isApproxToConstant ( const Scalar & value,
RealScalar prec = NumTraits<Scalar>::dummy_precision() ) const
Returns
true if all coefficients in this matrix are approximately equal to value, to within precision prec

References value().

Referenced by isOnes().

◆ isConstant()

template<typename Derived>
bool isConstant ( const Scalar & value,
RealScalar prec = NumTraits<Scalar>::dummy_precision() ) const

This is just an alias for isApproxToConstant().

Returns
true if all coefficients in this matrix are approximately equal to value, to within precision prec

◆ isMuchSmallerThan() [1/2]

template<typename Derived>
template<typename OtherDerived>
bool isMuchSmallerThan ( const DenseBase< OtherDerived > & other,
RealScalar prec = NumTraits<Scalar>::dummy_precision() ) const
Returns
true if the norm of *this is much smaller than the norm of other, within the precision determined by prec.
Note
The fuzzy compares are done multiplicatively. A vector $ v $ is considered to be much smaller than a vector $ w $ within precision $ p $ if

\[ \Vert v \Vert \leqslant p\,\Vert w\Vert. \]

For matrices, the comparison is done using the Hilbert-Schmidt norm.
See also
isApprox(), isMuchSmallerThan(const RealScalar&, RealScalar) const

References DenseBase().

◆ isMuchSmallerThan() [2/2]

template<typename Derived>
template<typename Derived>
bool isMuchSmallerThan ( const typename NumTraits< Scalar >::Real & other,
RealScalar prec ) const
Returns
true if the norm of *this is much smaller than other, within the precision determined by prec.
Note
The fuzzy compares are done multiplicatively. A vector $ v $ is considered to be much smaller than $ x $ within precision $ p $ if

\[ \Vert v \Vert \leqslant p\,\vert x\vert. \]

For matrices, the comparison is done using the Hilbert-Schmidt norm. For this reason, the value of the reference scalar other should come from the Hilbert-Schmidt norm of a reference matrix of same dimensions.

See also
isApprox(), isMuchSmallerThan(const DenseBase<OtherDerived>&, RealScalar) const

◆ isOnes()

template<typename Derived>
bool isOnes ( RealScalar prec = NumTraits<Scalar>::dummy_precision()) const
Returns
true if *this is approximately equal to the matrix where all coefficients are equal to 1, within the precision given by prec.

Example:

Matrix3d m = Matrix3d::Ones();
m(0,2) += 1e-4;
cout << "Here's the matrix m:" << endl << m << endl;
cout << "m.isOnes() returns: " << m.isOnes() << endl;
cout << "m.isOnes(1e-3) returns: " << m.isOnes(1e-3) << endl;
bool isOnes(RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
Definition CwiseNullaryOp.h:612

Output:

Here's the matrix m:
1 1 1
1 1 1
1 1 1
m.isOnes() returns: 0
m.isOnes(1e-3) returns: 1
See also
class CwiseNullaryOp, Ones()

References isApproxToConstant().

◆ isZero()

template<typename Derived>
bool isZero ( RealScalar prec = NumTraits<Scalar>::dummy_precision()) const
Returns
true if *this is approximately equal to the zero matrix, within the precision given by prec.

Example:

Matrix3d m = Matrix3d::Zero();
m(0,2) = 1e-4;
cout << "Here's the matrix m:" << endl << m << endl;
cout << "m.isZero() returns: " << m.isZero() << endl;
cout << "m.isZero(1e-3) returns: " << m.isZero(1e-3) << endl;
bool isZero(RealScalar prec=NumTraits< Scalar >::dummy_precision()) const
Definition CwiseNullaryOp.h:482

Output:

Here's the matrix m:
     0      0 0.0001
     0      0      0
     0      0      0
m.isZero() returns: 0
m.isZero(1e-3) returns: 1
See also
class CwiseNullaryOp, Zero()

◆ leftCols() [1/4]

template<typename Derived>
template<int N>
NColsBlockXpr< N >::Type leftCols ( )
inline
Returns
a block consisting of the left columns of *this.
Template Parameters
Nthe number of columns in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.leftCols<2>():" << endl;
cout << a.leftCols<2>() << endl;
a.leftCols<2>().setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.leftCols<2>():
 7  9
-2 -6
 6 -3
 6  6
Now the array a is:
 0  0 -5 -3
 0  0  1  0
 0  0  0  9
 0  0  3  9
See also
class Block, block(Index,Index,Index,Index)

References col(), and row().

◆ leftCols() [2/4]

template<typename Derived>
template<int N>
ConstNColsBlockXpr< N >::Type leftCols ( ) const
inline

This is the const version of leftCols<int>().

◆ leftCols() [3/4]

template<typename Derived>
ColsBlockXpr leftCols ( Index n)
inline
Returns
a block consisting of the left columns of *this.
Parameters
nthe number of columns in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.leftCols(2):" << endl;
cout << a.leftCols(2) << endl;
a.leftCols(2).setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.leftCols(2):
 7  9
-2 -6
 6 -3
 6  6
Now the array a is:
 0  0 -5 -3
 0  0  1  0
 0  0  0  9
 0  0  3  9
See also
class Block, block(Index,Index,Index,Index)

◆ leftCols() [4/4]

template<typename Derived>
ConstColsBlockXpr leftCols ( Index n) const
inline

This is the const version of leftCols(Index).

◆ LinSpaced() [1/4]

template<typename Derived>
const DenseBase< Derived >::RandomAccessLinSpacedReturnType LinSpaced ( const Scalar & low,
const Scalar & high )
inlinestatic

Sets a linearly space vector.

The function generates 'size' equally spaced values in the closed interval [low,high]. When size is set to 1, a vector of length 1 containing 'high' is returned.

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:

cout << VectorXi::LinSpaced(4,7,10).transpose() << endl;
cout << VectorXd::LinSpaced(5,0.0,1.0).transpose() << endl;
static const SequentialLinSpacedReturnType LinSpaced(Sequential_t, Index size, const Scalar &low, const Scalar &high)
Definition CwiseNullaryOp.h:242

Output:

 7  8  9 10
   0 0.25  0.5 0.75    1
See also
setLinSpaced(Index,const Scalar&,const Scalar&), LinSpaced(Sequential_t,Index,const Scalar&,const Scalar&,Index), CwiseNullaryOp Special version for fixed size types which does not require the size parameter.

References NullaryExpr().

◆ LinSpaced() [2/4]

template<typename Derived>
const DenseBase< Derived >::RandomAccessLinSpacedReturnType LinSpaced ( Index size,
const Scalar & low,
const Scalar & high )
inlinestatic

Sets a linearly space vector.

The function generates 'size' equally spaced values in the closed interval [low,high]. When size is set to 1, a vector of length 1 containing 'high' is returned.

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:

cout << VectorXi::LinSpaced(4,7,10).transpose() << endl;
cout << VectorXd::LinSpaced(5,0.0,1.0).transpose() << endl;

Output:

 7  8  9 10
   0 0.25  0.5 0.75    1
See also
setLinSpaced(Index,const Scalar&,const Scalar&), LinSpaced(Sequential_t,Index,const Scalar&,const Scalar&,Index), CwiseNullaryOp

References NullaryExpr().

◆ LinSpaced() [3/4]

template<typename Derived>
const DenseBase< Derived >::SequentialLinSpacedReturnType LinSpaced ( Sequential_t ,
const Scalar & low,
const Scalar & high )
inlinestatic

Sets a linearly space vector.

The function generates 'size' equally spaced values in the closed interval [low,high]. This particular version of LinSpaced() uses sequential access, i.e. vector access is assumed to be a(0), a(1), ..., a(size). This assumption allows for better vectorization and yields faster code than the random access version.

When size is set to 1, a vector of length 1 containing 'high' is returned.

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:

cout << VectorXi::LinSpaced(Sequential,4,7,10).transpose() << endl;
cout << VectorXd::LinSpaced(Sequential,5,0.0,1.0).transpose() << endl;

Output:

 7  8  9 10
   0 0.25  0.5 0.75    1
See also
setLinSpaced(Index,const Scalar&,const Scalar&), LinSpaced(Index,Scalar,Scalar), CwiseNullaryOp Special version for fixed size types which does not require the size parameter.

◆ LinSpaced() [4/4]

template<typename Derived>
const DenseBase< Derived >::SequentialLinSpacedReturnType LinSpaced ( Sequential_t ,
Index size,
const Scalar & low,
const Scalar & high )
inlinestatic

Sets a linearly space vector.

The function generates 'size' equally spaced values in the closed interval [low,high]. This particular version of LinSpaced() uses sequential access, i.e. vector access is assumed to be a(0), a(1), ..., a(size). This assumption allows for better vectorization and yields faster code than the random access version.

When size is set to 1, a vector of length 1 containing 'high' is returned.

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:

cout << VectorXi::LinSpaced(Sequential,4,7,10).transpose() << endl;
cout << VectorXd::LinSpaced(Sequential,5,0.0,1.0).transpose() << endl;

Output:

 7  8  9 10
   0 0.25  0.5 0.75    1
See also
setLinSpaced(Index,const Scalar&,const Scalar&), LinSpaced(Index,Scalar,Scalar), CwiseNullaryOp

References NullaryExpr().

◆ maxCoeff() [1/3]

template<typename Derived>
internal::traits< Derived >::Scalar maxCoeff ( ) const
inline
Returns
the maximum of all coefficients of *this

◆ maxCoeff() [2/3]

template<typename Derived>
template<typename IndexType>
internal::traits< Derived >::Scalar maxCoeff ( IndexType * index) const
Returns
the maximum of all coefficients of *this and puts in *index its location.
See also
DenseBase::maxCoeff(IndexType*,IndexType*), DenseBase::minCoeff(IndexType*,IndexType*), DenseBase::visitor(), DenseBase::maxCoeff()

References RowsAtCompileTime, and visit().

◆ maxCoeff() [3/3]

template<typename Derived>
template<typename IndexType>
internal::traits< Derived >::Scalar maxCoeff ( IndexType * row,
IndexType * col ) const
Returns
the maximum of all coefficients of *this and puts in *row and *col its location.
See also
DenseBase::minCoeff(IndexType*,IndexType*), DenseBase::visitor(), DenseBase::maxCoeff()

References col(), row(), and visit().

◆ mean()

template<typename Derived>
internal::traits< Derived >::Scalar mean ( ) const
inline
Returns
the mean of all coefficients of *this
See also
trace(), prod(), sum()

◆ middleCols() [1/4]

template<typename Derived>
template<int N>
NColsBlockXpr< N >::Type middleCols ( Index startCol)
inline
Returns
a block consisting of a range of columns of *this.
Template Parameters
Nthe number of columns in the block
Parameters
startColthe index of the first column in the block

Example:

#include <Eigen/Core>
#include <iostream>
using namespace Eigen;
using namespace std;
int main(void)
{
int const N = 5;
MatrixXi A(N,N);
A.setRandom();
cout << "A =\n" << A << '\n' << endl;
cout << "A(:,1..3) =\n" << A.middleCols<3>(1) << endl;
return 0;
}

Output:

A =
  7  -6   0   9 -10
 -2  -3   3   3  -5
  6   6  -3   5  -8
  6  -5   0  -8   6
  9   1   9   2  -7

A(:,1..3) =
-6  0  9
-3  3  3
 6 -3  5
-5  0 -8
 1  9  2
See also
class Block, block(Index,Index,Index,Index)

◆ middleCols() [2/4]

template<typename Derived>
template<int N>
ConstNColsBlockXpr< N >::Type middleCols ( Index startCol) const
inline

This is the const version of middleCols<int>().

◆ middleCols() [3/4]

template<typename Derived>
ColsBlockXpr middleCols ( Index startCol,
Index numCols )
inline
Returns
a block consisting of a range of columns of *this.
Parameters
startColthe index of the first column in the block
numColsthe number of columns in the block

Example:

#include <Eigen/Core>
#include <iostream>
using namespace Eigen;
using namespace std;
int main(void)
{
int const N = 5;
MatrixXi A(N,N);
A.setRandom();
cout << "A =\n" << A << '\n' << endl;
cout << "A(1..3,:) =\n" << A.middleCols(1,3) << endl;
return 0;
}

Output:

A =
  7  -6   0   9 -10
 -2  -3   3   3  -5
  6   6  -3   5  -8
  6  -5   0  -8   6
  9   1   9   2  -7

A(1..3,:) =
-6  0  9
-3  3  3
 6 -3  5
-5  0 -8
 1  9  2
See also
class Block, block(Index,Index,Index,Index)

References reverse(), and reverseInPlace().

◆ middleCols() [4/4]

template<typename Derived>
ConstColsBlockXpr middleCols ( Index startCol,
Index numCols ) const
inline

This is the const version of middleCols(Index,Index).

◆ middleRows() [1/4]

template<typename Derived>
template<int N>
NRowsBlockXpr< N >::Type middleRows ( Index startRow)
inline
Returns
a block consisting of a range of rows of *this.
Template Parameters
Nthe number of rows in the block
Parameters
startRowthe index of the first row in the block

Example:

#include <Eigen/Core>
#include <iostream>
using namespace Eigen;
using namespace std;
int main(void)
{
int const N = 5;
MatrixXi A(N,N);
A.setRandom();
cout << "A =\n" << A << '\n' << endl;
cout << "A(1..3,:) =\n" << A.middleRows<3>(1) << endl;
return 0;
}

Output:

A =
  7  -6   0   9 -10
 -2  -3   3   3  -5
  6   6  -3   5  -8
  6  -5   0  -8   6
  9   1   9   2  -7

A(1..3,:) =
-2 -3  3  3 -5
 6  6 -3  5 -8
 6 -5  0 -8  6
See also
class Block, block(Index,Index,Index,Index)

◆ middleRows() [2/4]

template<typename Derived>
template<int N>
ConstNRowsBlockXpr< N >::Type middleRows ( Index startRow) const
inline

This is the const version of middleRows<int>().

◆ middleRows() [3/4]

template<typename Derived>
RowsBlockXpr middleRows ( Index startRow,
Index numRows )
inline
Returns
a block consisting of a range of rows of *this.
Parameters
startRowthe index of the first row in the block
numRowsthe number of rows in the block

Example:

#include <Eigen/Core>
#include <iostream>
using namespace Eigen;
using namespace std;
int main(void)
{
int const N = 5;
MatrixXi A(N,N);
A.setRandom();
cout << "A =\n" << A << '\n' << endl;
cout << "A(2..3,:) =\n" << A.middleRows(2,2) << endl;
return 0;
}

Output:

A =
  7  -6   0   9 -10
 -2  -3   3   3  -5
  6   6  -3   5  -8
  6  -5   0  -8   6
  9   1   9   2  -7

A(2..3,:) =
 6  6 -3  5 -8
 6 -5  0 -8  6
See also
class Block, block(Index,Index,Index,Index)

References DenseBase().

◆ middleRows() [4/4]

template<typename Derived>
ConstRowsBlockXpr middleRows ( Index startRow,
Index numRows ) const
inline

This is the const version of middleRows(Index,Index).

References DenseBase(), and value().

◆ minCoeff() [1/3]

template<typename Derived>
internal::traits< Derived >::Scalar minCoeff ( ) const
inline
Returns
the minimum of all coefficients of *this

◆ minCoeff() [2/3]

template<typename Derived>
template<typename IndexType>
internal::traits< Derived >::Scalar minCoeff ( IndexType * index) const
Returns
the minimum of all coefficients of *this and puts in *index its location.
See also
DenseBase::minCoeff(IndexType*,IndexType*), DenseBase::maxCoeff(IndexType*,IndexType*), DenseBase::visitor(), DenseBase::minCoeff()

References RowsAtCompileTime, and visit().

◆ minCoeff() [3/3]

template<typename Derived>
template<typename IndexType>
internal::traits< Derived >::Scalar minCoeff ( IndexType * row,
IndexType * col ) const
Returns
the minimum of all coefficients of *this and puts in *row and *col its location.
See also
DenseBase::minCoeff(Index*), DenseBase::maxCoeff(Index*,Index*), DenseBase::visitor(), DenseBase::minCoeff()

References col(), row(), and visit().

◆ nestByValue()

template<typename Derived>
const NestByValue< Derived > nestByValue ( ) const
inline
Returns
an expression of the temporary version of *this.

◆ nonZeros()

template<typename Derived>
Index nonZeros ( ) const
inline
Returns
the number of nonzero coefficients which is in practice the number of stored coefficients.

◆ NullaryExpr() [1/3]

template<typename Derived>
template<typename CustomNullaryOp>
const CwiseNullaryOp< CustomNullaryOp, Derived > NullaryExpr ( const CustomNullaryOp & func)
inlinestatic
Returns
an expression of a matrix defined by a custom functor func

This variant is only for fixed-size DenseBase types. For dynamic-size types, you need to use the variants taking size arguments.

The template parameter CustomNullaryOp is the type of the functor.

See also
class CwiseNullaryOp

References ColsAtCompileTime, and RowsAtCompileTime.

◆ NullaryExpr() [2/3]

template<typename Derived>
template<typename CustomNullaryOp>
const CwiseNullaryOp< CustomNullaryOp, Derived > NullaryExpr ( Index rows,
Index cols,
const CustomNullaryOp & func )
inlinestatic
Returns
an expression of a matrix defined by a custom functor func

The parameters rows and cols are the number of rows and of columns of the returned matrix. Must be compatible with this MatrixBase type.

This variant is meant to be used for dynamic-size matrix types. For fixed-size types, it is redundant to pass rows and cols as arguments, so Zero() should be used instead.

The template parameter CustomNullaryOp is the type of the functor.

See also
class CwiseNullaryOp

Referenced by Constant(), Constant(), Constant(), MatrixBase< Derived >::Identity(), MatrixBase< Derived >::Identity(), LinSpaced(), LinSpaced(), LinSpaced(), Random(), Random(), Random(), and MatrixBase< MatrixWrapper< ExpressionType > >::UnitW().

◆ NullaryExpr() [3/3]

template<typename Derived>
template<typename CustomNullaryOp>
const CwiseNullaryOp< CustomNullaryOp, Derived > NullaryExpr ( Index size,
const CustomNullaryOp & func )
inlinestatic
Returns
an expression of a matrix defined by a custom functor func

The parameter size is the size of the returned vector. Must be compatible with this MatrixBase type.

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.

This variant is meant to be used for dynamic-size vector types. For fixed-size types, it is redundant to pass size as argument, so Zero() should be used instead.

The template parameter CustomNullaryOp is the type of the functor.

See also
class CwiseNullaryOp

References RowsAtCompileTime.

◆ Ones() [1/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Ones ( )
inlinestatic
Returns
an expression of a fixed-size matrix or vector where all coefficients equal one.

This variant is only for fixed-size MatrixBase types. For dynamic-size types, you need to use the variants taking size arguments.

Example:

cout << Matrix2d::Ones() << endl;
cout << 6 * RowVector4i::Ones() << endl;

Output:

1 1
1 1
6 6 6 6
See also
Ones(Index), Ones(Index,Index), isOnes(), class Ones

References Constant().

◆ Ones() [2/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Ones ( Index rows,
Index cols )
inlinestatic
Returns
an expression of a matrix where all coefficients equal one.

The parameters rows and cols are the number of rows and of columns of the returned matrix. Must be compatible with this MatrixBase type.

This variant is meant to be used for dynamic-size matrix types. For fixed-size types, it is redundant to pass rows and cols as arguments, so Ones() should be used instead.

Example:

cout << MatrixXi::Ones(2,3) << endl;

Output:

1 1 1
1 1 1
See also
Ones(), Ones(Index), isOnes(), class Ones

References Constant().

◆ Ones() [3/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Ones ( Index size)
inlinestatic
Returns
an expression of a vector where all coefficients equal one.

The parameter size is the size of the returned vector. Must be compatible with this MatrixBase type.

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.

This variant is meant to be used for dynamic-size vector types. For fixed-size types, it is redundant to pass size as argument, so Ones() should be used instead.

Example:

cout << 6 * RowVectorXi::Ones(4) << endl;
cout << VectorXf::Ones(2) << endl;

Output:

6 6 6 6
1
1
See also
Ones(), Ones(Index,Index), isOnes(), class Ones

References Constant().

◆ operator<<() [1/2]

template<typename Derived>
template<typename OtherDerived>
CommaInitializer< Derived > operator<< ( const DenseBase< OtherDerived > & other)
inline

◆ operator<<() [2/2]

template<typename Derived>
CommaInitializer< Derived > operator<< ( const Scalar & s)
inline

Convenient operator to set the coefficients of a matrix.

The coefficients must be provided in a row major order and exactly match the size of the matrix. Otherwise an assertion is raised.

Example:

Matrix3i m1;
m1 << 1, 2, 3,
4, 5, 6,
7, 8, 9;
cout << m1 << endl << endl;
Matrix3i m2 = Matrix3i::Identity();
m2.block(0,0, 2,2) << 10, 11, 12, 13;
cout << m2 << endl << endl;
Vector2i v1;
v1 << 14, 15;
m2 << v1.transpose(), 16,
v1, m1.block(1,1,2,2);
cout << m2 << endl;

Output:

1 2 3
4 5 6
7 8 9

10 11  0
12 13  0
 0  0  1

14 15 16
14  5  6
15  8  9
See also
CommaInitializer::finished(), class CommaInitializer

◆ operator=() [1/3]

template<typename Derived>
Derived & operator= ( const DenseBase< Derived > & other)
inline

Special case of the template operator=, in order to prevent the compiler from generating a default operator= (issue hit with g++ 4.1)

References DenseBase().

◆ operator=() [2/3]

template<typename Derived>
template<typename OtherDerived>
Derived & operator= ( const DenseBase< OtherDerived > & other)
inline

Copies other into *this.

Returns
a reference to *this.

References DenseBase().

◆ operator=() [3/3]

template<typename Derived>
template<typename OtherDerived>
Derived & operator= ( const EigenBase< OtherDerived > & other)

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

Returns
a reference to *this.

References EigenBase< Derived >::derived().

◆ outerSize()

template<typename Derived>
Index outerSize ( ) const
inline
Returns
true if either the number of rows or the number of columns is equal to 1. In other words, this function returns
rows()==1 || cols()==1
See also
rows(), cols(), IsVectorAtCompileTime.
Returns
the outer size.
Note
For a vector, this returns just 1. For a matrix (non-vector), this is the major dimension with respect to the storage order, i.e., the number of columns for a column-major matrix, and the number of rows for a row-major matrix.

References IsRowMajor, and IsVectorAtCompileTime.

◆ prod()

template<typename Derived>
internal::traits< Derived >::Scalar prod ( ) const
inline
Returns
the product of all coefficients of *this

Example:

Matrix3d m = Matrix3d::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is the product of all the coefficients:" << endl << m.prod() << endl;

Output:

Here is the matrix m:
  0.68  0.597  -0.33
-0.211  0.823  0.536
 0.566 -0.605 -0.444
Here is the product of all the coefficients:
0.0019
See also
sum(), mean(), trace()

References SizeAtCompileTime.

◆ Random() [1/3]

template<typename Derived>
const CwiseNullaryOp< internal::scalar_random_op< typename internal::traits< Derived >::Scalar >, Derived > Random ( )
inlinestatic
Returns
a fixed-size random matrix or vector expression

This variant is only for fixed-size MatrixBase types. For dynamic-size types, you need to use the variants taking size arguments.

Example:

cout << 100 * Matrix2i::Random() << endl;

Output:

700 600
-200 600

This expression has the "evaluate before nesting" flag so that it will be evaluated into a temporary matrix whenever it is nested in a larger expression. This prevents unexpected behavior with expressions involving random matrices.

See also
MatrixBase::setRandom(), MatrixBase::Random(Index,Index), MatrixBase::Random(Index)

References ColsAtCompileTime, NullaryExpr(), and RowsAtCompileTime.

◆ Random() [2/3]

template<typename Derived>
const CwiseNullaryOp< internal::scalar_random_op< typename internal::traits< Derived >::Scalar >, Derived > Random ( Index rows,
Index cols )
inlinestatic
Returns
a random matrix expression

The parameters rows and cols are the number of rows and of columns of the returned matrix. Must be compatible with this MatrixBase type.

This variant is meant to be used for dynamic-size matrix types. For fixed-size types, it is redundant to pass rows and cols as arguments, so Random() should be used instead.

Example:

cout << MatrixXi::Random(2,3) << endl;

Output:

 7  6  9
-2  6 -6

This expression has the "evaluate before nesting" flag so that it will be evaluated into a temporary matrix whenever it is nested in a larger expression. This prevents unexpected behavior with expressions involving random matrices.

See also
MatrixBase::setRandom(), MatrixBase::Random(Index), MatrixBase::Random()

References NullaryExpr().

Referenced by rightCols(), rightCols(), and setRandom().

◆ Random() [3/3]

template<typename Derived>
const CwiseNullaryOp< internal::scalar_random_op< typename internal::traits< Derived >::Scalar >, Derived > Random ( Index size)
inlinestatic
Returns
a random vector expression

The parameter size is the size of the returned vector. Must be compatible with this MatrixBase type.

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.

This variant is meant to be used for dynamic-size vector types. For fixed-size types, it is redundant to pass size as argument, so Random() should be used instead.

Example:

cout << VectorXi::Random(2) << endl;

Output:

7
-2

This expression has the "evaluate before nesting" flag so that it will be evaluated into a temporary vector whenever it is nested in a larger expression. This prevents unexpected behavior with expressions involving random matrices.

See also
MatrixBase::setRandom(), MatrixBase::Random(Index,Index), MatrixBase::Random()

References NullaryExpr().

◆ redux()

template<typename Derived>
template<typename Func>
internal::result_of< Func(typenameinternal::traits< Derived >::Scalar)>::type redux ( const Func & func) const
inline
Returns
the result of a full redux operation on the whole matrix or vector using func

The template parameter BinaryOp is the type of the functor func which must be an associative operator. Both current STL and TR1 functor styles are handled.

See also
DenseBase::sum(), DenseBase::minCoeff(), DenseBase::maxCoeff(), MatrixBase::colwise(), MatrixBase::rowwise()

◆ replicate() [1/2]

template<typename Derived>
template<int RowFactor, int ColFactor>
const Replicate< Derived, RowFactor, ColFactor > replicate ( ) const
inline
Returns
an expression of the replication of *this

Example:

MatrixXi m = MatrixXi::Random(2,3);
cout << "Here is the matrix m:" << endl << m << endl;
cout << "m.replicate<3,2>() = ..." << endl;
cout << m.replicate<3,2>() << endl;
const Replicate< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols >, RowFactor, ColFactor > replicate() const
Definition Replicate.h:139

Output:

Here is the matrix m:
 7  6  9
-2  6 -6
m.replicate<3,2>() = ...
 7  6  9  7  6  9
-2  6 -6 -2  6 -6
 7  6  9  7  6  9
-2  6 -6 -2  6 -6
 7  6  9  7  6  9
-2  6 -6 -2  6 -6
See also
VectorwiseOp::replicate(), DenseBase::replicate(Index,Index), class Replicate

Referenced by rightCols().

◆ replicate() [2/2]

template<typename Derived>
const Replicate< Derived, Dynamic, Dynamic > replicate ( Index rowFactor,
Index colFactor ) const
inline
Returns
an expression of the replication of *this

Example:

Vector3i v = Vector3i::Random();
cout << "Here is the vector v:" << endl << v << endl;
cout << "v.replicate(2,5) = ..." << endl;
cout << v.replicate(2,5) << endl;

Output:

Here is the vector v:
7
-2
6
v.replicate(2,5) = ...
 7  7  7  7  7
-2 -2 -2 -2 -2
 6  6  6  6  6
 7  7  7  7  7
-2 -2 -2 -2 -2
 6  6  6  6  6
See also
VectorwiseOp::replicate(), DenseBase::replicate<int,int>(), class Replicate

◆ resize() [1/2]

template<typename Derived>
void resize ( Index rows,
Index cols )
inline

Only plain matrices/arrays, not expressions, may be resized; therefore the only useful resize methods are Matrix::resize() and Array::resize(). The present method only asserts that the new size equals the old size, and does nothing else.

◆ resize() [2/2]

template<typename Derived>
void resize ( Index size)
inline

Only plain matrices/arrays, not expressions, may be resized; therefore the only useful resize methods are Matrix::resize() and Array::resize(). The present method only asserts that the new size equals the old size, and does nothing else.

◆ reverse() [1/2]

template<typename Derived>
DenseBase< Derived >::ReverseReturnType reverse ( )
inline
Returns
an expression of the reverse of *this.

Example:

MatrixXi m = MatrixXi::Random(3,4);
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is the reverse of m:" << endl << m.reverse() << endl;
cout << "Here is the coefficient (1,0) in the reverse of m:" << endl
<< m.reverse()(1,0) << endl;
cout << "Let us overwrite this coefficient with the value 4." << endl;
m.reverse()(1,0) = 4;
cout << "Now the matrix m is:" << endl << m << endl;

Output:

Here is the matrix m:
 7  6 -3  1
-2  9  6  0
 6 -6 -5  3
Here is the reverse of m:
 3 -5 -6  6
 0  6  9 -2
 1 -3  6  7
Here is the coefficient (1,0) in the reverse of m:
0
Let us overwrite this coefficient with the value 4.
Now the matrix m is:
 7  6 -3  1
-2  9  6  4
 6 -6 -5  3

Referenced by middleCols().

◆ reverse() [2/2]

template<typename Derived>
const DenseBase< Derived >::ConstReverseReturnType reverse ( ) const
inline

This is the const version of reverse().

◆ reverseInPlace()

template<typename Derived>
void reverseInPlace ( )
inline

This is the "in place" version of reverse: it reverses *this.

In most cases it is probably better to simply use the reversed expression of a matrix. However, when reversing the matrix data itself is really needed, then this "in-place" version is probably the right choice because it provides the following additional features:

  • less error prone: doing the same operation with .reverse() requires special care:
    m = m.reverse().eval();
  • this API allows to avoid creating a temporary (the current implementation creates a temporary, but that could be avoided using swap)
  • it allows future optimizations (cache friendliness, etc.)
See also
reverse()

Referenced by middleCols().

◆ rightCols() [1/4]

template<typename Derived>
template<int N>
NColsBlockXpr< N >::Type rightCols ( )
inline
Returns
a block consisting of the right columns of *this.
Template Parameters
Nthe number of columns in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.rightCols<2>():" << endl;
cout << a.rightCols<2>() << endl;
a.rightCols<2>().setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.rightCols<2>():
-5 -3
 1  0
 0  9
 3  9
Now the array a is:
 7  9  0  0
-2 -6  0  0
 6 -3  0  0
 6  6  0  0
See also
class Block, block(Index,Index,Index,Index)

References DenseBase(), Random(), and select().

◆ rightCols() [2/4]

template<typename Derived>
template<int N>
ConstNColsBlockXpr< N >::Type rightCols ( ) const
inline

This is the const version of rightCols<int>().

References Eigen::BothDirections, DenseBase(), replicate(), and select().

◆ rightCols() [3/4]

template<typename Derived>
ColsBlockXpr rightCols ( Index n)
inline
Returns
a block consisting of the right columns of *this.
Parameters
nthe number of columns in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.rightCols(2):" << endl;
cout << a.rightCols(2) << endl;
a.rightCols(2).setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.rightCols(2):
-5 -3
 1  0
 0  9
 3  9
Now the array a is:
 7  9  0  0
-2 -6  0  0
 6 -3  0  0
 6  6  0  0
See also
class Block, block(Index,Index,Index,Index)

◆ rightCols() [4/4]

template<typename Derived>
ConstColsBlockXpr rightCols ( Index n) const
inline

This is the const version of rightCols(Index).

References all(), any(), colwise(), count(), Eigen::Horizontal, Random(), rowwise(), and Eigen::Vertical.

◆ row() [1/2]

template<typename Derived>
RowXpr row ( Index i)
inline

◆ row() [2/2]

template<typename Derived>
ConstRowXpr row ( Index i) const
inline

This is the const version of row().

◆ rowwise() [1/2]

template<typename Derived>
DenseBase< Derived >::RowwiseReturnType rowwise ( )
inline
Returns
a writable VectorwiseOp wrapper of *this providing additional partial reduction operations
See also
colwise(), class VectorwiseOp, Tutorial page 7 - Reductions, visitors and broadcasting

References rowwise().

◆ rowwise() [2/2]

template<typename Derived>
const DenseBase< Derived >::ConstRowwiseReturnType rowwise ( ) const
inline
Returns
a VectorwiseOp wrapper of *this providing additional partial reduction operations

Example:

Matrix3d m = Matrix3d::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is the sum of each row:" << endl << m.rowwise().sum() << endl;
cout << "Here is the maximum absolute value of each row:"
<< endl << m.cwiseAbs().rowwise().maxCoeff() << endl;
ConstRowwiseReturnType rowwise() const
Definition VectorwiseOp.h:580

Output:

Here is the matrix m:
  0.68  0.597  -0.33
-0.211  0.823  0.536
 0.566 -0.605 -0.444
Here is the sum of each row:
0.948
1.15
-0.483
Here is the maximum absolute value of each row:
0.68
0.823
0.605
See also
colwise(), class VectorwiseOp, Tutorial page 7 - Reductions, visitors and broadcasting

References rowwise().

Referenced by rightCols(), rowwise(), rowwise(), and Eigen::umeyama().

◆ segment() [1/4]

template<typename Derived>
template<int Size>
DenseBase< Derived >::template FixedSegmentReturnType< Size >::Type segment ( Index start)
inline
Returns
a fixed-size expression of a segment (i.e. a vector block) in *this

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.

The template parameter Size is the number of coefficients in the block

Parameters
startthe index of the first element of the sub-vector

Example:

RowVector4i v = RowVector4i::Random();
cout << "Here is the vector v:" << endl << v << endl;
cout << "Here is v.segment<2>(1):" << endl << v.segment<2>(1) << endl;
v.segment<2>(2).setZero();
cout << "Now the vector v is:" << endl << v << endl;
SegmentReturnType segment(Index start, Index size)
Definition VectorBlock.h:111

Output:

Here is the vector v:
 7 -2  6  6
Here is v.segment<2>(1):
-2 6
Now the vector v is:
 7 -2  0  0
See also
class Block

◆ segment() [2/4]

template<typename Derived>
template<int Size>
DenseBase< Derived >::template ConstFixedSegmentReturnType< Size >::Type segment ( Index start) const
inline

This is the const version of segment<int>(Index).

◆ segment() [3/4]

template<typename Derived>
DenseBase< Derived >::SegmentReturnType segment ( Index start,
Index size )
inline
Returns
a dynamic-size expression of a segment (i.e. a vector block) in *this.

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.

Parameters
startthe first coefficient in the segment
sizethe number of coefficients in the segment

Example:

RowVector4i v = RowVector4i::Random();
cout << "Here is the vector v:" << endl << v << endl;
cout << "Here is v.segment(1, 2):" << endl << v.segment(1, 2) << endl;
v.segment(1, 2).setZero();
cout << "Now the vector v is:" << endl << v << endl;

Output:

Here is the vector v:
 7 -2  6  6
Here is v.segment(1, 2):
-2 6
Now the vector v is:
7 0 0 6
Note
Even though the returned expression has dynamic size, in the case when it is applied to a fixed-size vector, it inherits a fixed maximal size, which means that evaluating it does not cause a dynamic memory allocation.
See also
class Block, segment(Index)

Referenced by MatrixBase< Derived >::stableNorm().

◆ segment() [4/4]

template<typename Derived>
DenseBase< Derived >::ConstSegmentReturnType segment ( Index start,
Index size ) const
inline

This is the const version of segment(Index,Index).

◆ select() [1/3]

template<typename Derived>
template<typename ThenDerived, typename ElseDerived>
const Select< Derived, ThenDerived, ElseDerived > select ( const DenseBase< ThenDerived > & thenMatrix,
const DenseBase< ElseDerived > & elseMatrix ) const
inline
Returns
a matrix where each coefficient (i,j) is equal to thenMatrix(i,j) if *this(i,j), and elseMatrix(i,j) otherwise.

Example:

MatrixXi m(3, 3);
m << 1, 2, 3,
4, 5, 6,
7, 8, 9;
m = (m.array() >= 5).select(-m, m);
cout << m << endl;

Output:

 1  2  3
 4 -5 -6
-7 -8 -9
See also
class Select

References DenseBase().

Referenced by rightCols(), and rightCols().

◆ select() [2/3]

template<typename Derived>
template<typename ThenDerived>
const Select< Derived, ThenDerived, typename ThenDerived::ConstantReturnType > select ( const DenseBase< ThenDerived > & thenMatrix,
typename ThenDerived::Scalar elseScalar ) const
inline

Version of DenseBase::select(const DenseBase&, const DenseBase&) with the else expression being a scalar value.

See also
DenseBase::select(const DenseBase<ThenDerived>&, const DenseBase<ElseDerived>&) const, class Select

References DenseBase().

◆ select() [3/3]

template<typename Derived>
template<typename ElseDerived>
const Select< Derived, typename ElseDerived::ConstantReturnType, ElseDerived > select ( typename ElseDerived::Scalar thenScalar,
const DenseBase< ElseDerived > & elseMatrix ) const
inline

Version of DenseBase::select(const DenseBase&, const DenseBase&) with the then expression being a scalar value.

See also
DenseBase::select(const DenseBase<ThenDerived>&, const DenseBase<ElseDerived>&) const, class Select

References DenseBase().

◆ setConstant()

template<typename Derived>
Derived & setConstant ( const Scalar & value)
inline

Sets all coefficients in this expression to value.

See also
fill(), setConstant(Index,const Scalar&), setConstant(Index,Index,const Scalar&), setZero(), setOnes(), Constant(), class CwiseNullaryOp, setZero(), setOnes()

Referenced by fill(), setOnes(), and setZero().

◆ setLinSpaced() [1/2]

template<typename Derived>
Derived & setLinSpaced ( const Scalar & low,
const Scalar & high )
inline

Sets a linearly space vector.

The function fill *this with equally spaced values in the closed interval [low,high]. When size is set to 1, a vector of length 1 containing 'high' is returned.

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.

See also
setLinSpaced(Index, const Scalar&, const Scalar&), CwiseNullaryOp

References setLinSpaced().

◆ setLinSpaced() [2/2]

template<typename Derived>
Derived & setLinSpaced ( Index size,
const Scalar & low,
const Scalar & high )
inline

Sets a linearly space vector.

The function generates 'size' equally spaced values in the closed interval [low,high]. When size is set to 1, a vector of length 1 containing 'high' is returned.

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:

VectorXf v;
v.setLinSpaced(5,0.5f,1.5f).transpose();
cout << v << endl;
Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > & setLinSpaced(Index size, const Scalar &low, const Scalar &high)
Definition CwiseNullaryOp.h:387

Output:

0.5
0.75
1
1.25
1.5
See also
CwiseNullaryOp

Referenced by setLinSpaced().

◆ setOnes()

template<typename Derived>
Derived & setOnes ( )
inline

Sets all coefficients in this expression to one.

Example:

Matrix4i m = Matrix4i::Random();
m.row(1).setOnes();
cout << m << endl;

Output:

 7  9 -5 -3
 1  1  1  1
 6 -3  0  9
 6  6  3  9
See also
class CwiseNullaryOp, Ones()

References setConstant().

◆ setRandom()

template<typename Derived>
Derived & setRandom ( )
inline

Sets all coefficients in this expression to random values.

Example:

Matrix4i m = Matrix4i::Zero();
m.col(1).setRandom();
cout << m << endl;

Output:

 0  7  0  0
 0 -2  0  0
 0  6  0  0
 0  6  0  0
See also
class CwiseNullaryOp, setRandom(Index), setRandom(Index,Index)

References Random().

◆ setZero()

template<typename Derived>
Derived & setZero ( )
inline

Sets all coefficients in this expression to zero.

Example:

Matrix4i m = Matrix4i::Random();
m.row(1).setZero();
cout << m << endl;

Output:

 7  9 -5 -3
 0  0  0  0
 6 -3  0  9
 6  6  3  9
See also
class CwiseNullaryOp, Zero()

References setConstant().

◆ sum()

template<typename Derived>
internal::traits< Derived >::Scalar sum ( ) const
inline
Returns
the sum of all coefficients of *this
See also
trace(), prod(), mean()

References SizeAtCompileTime.

◆ swap() [1/2]

template<typename Derived>
template<typename OtherDerived>
void swap ( const DenseBase< OtherDerived > & other,
int = OtherDerived::ThisConstantIsPrivateInPlainObjectBase )
inline

swaps *this with the expression other.

References DenseBase().

◆ swap() [2/2]

template<typename Derived>
template<typename OtherDerived>
void swap ( PlainObjectBase< OtherDerived > & other)
inline

swaps *this with the matrix or array other.

◆ tail() [1/4]

template<typename Derived>
template<int Size>
DenseBase< Derived >::template FixedSegmentReturnType< Size >::Type tail ( )
inline
Returns
a fixed-size expression of the last coefficients of *this.

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.

The template parameter Size is the number of coefficients in the block

Example:

RowVector4i v = RowVector4i::Random();
cout << "Here is the vector v:" << endl << v << endl;
cout << "Here is v.tail(2):" << endl << v.tail<2>() << endl;
v.tail<2>().setZero();
cout << "Now the vector v is:" << endl << v << endl;
SegmentReturnType tail(Index size)
Definition VectorBlock.h:175

Output:

Here is the vector v:
 7 -2  6  6
Here is v.tail(2):
6 6
Now the vector v is:
 7 -2  0  0
See also
class Block

◆ tail() [2/4]

template<typename Derived>
template<int Size>
DenseBase< Derived >::template ConstFixedSegmentReturnType< Size >::Type tail ( ) const
inline

This is the const version of tail<int>.

◆ tail() [3/4]

template<typename Derived>
DenseBase< Derived >::SegmentReturnType tail ( Index size)
inline
Returns
a dynamic-size expression of the last coefficients of *this.

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.

Parameters
sizethe number of coefficients in the block

Example:

RowVector4i v = RowVector4i::Random();
cout << "Here is the vector v:" << endl << v << endl;
cout << "Here is v.tail(2):" << endl << v.tail(2) << endl;
v.tail(2).setZero();
cout << "Now the vector v is:" << endl << v << endl;

Output:

Here is the vector v:
 7 -2  6  6
Here is v.tail(2):
6 6
Now the vector v is:
 7 -2  0  0
Note
Even though the returned expression has dynamic size, in the case when it is applied to a fixed-size vector, it inherits a fixed maximal size, which means that evaluating it does not cause a dynamic memory allocation.
See also
class Block, block(Index,Index)

References tail().

Referenced by bottomRows(), MatrixBase< Derived >::makeHouseholder(), tail(), tail(), DenseBase< ArrayWrapper< ExpressionType > >::tail(), and DenseBase< ArrayWrapper< ExpressionType > >::tail().

◆ tail() [4/4]

template<typename Derived>
DenseBase< Derived >::ConstSegmentReturnType tail ( Index size) const
inline

This is the const version of tail(Index).

References tail().

◆ topLeftCorner() [1/4]

template<typename Derived>
template<int CRows, int CCols>
Block< Derived, CRows, CCols > topLeftCorner ( )
inline
Returns
an expression of a fixed-size top-left corner of *this.

The template parameters CRows and CCols are the number of rows and columns in the corner.

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.topLeftCorner<2,2>():" << endl;
cout << m.topLeftCorner<2,2>() << endl;
cout << "Now the matrix m is:" << endl << m << endl;
Block< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > topLeftCorner(Index cRows, Index cCols)
Definition DenseBase.h:125

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.topLeftCorner<2,2>():
 7  9
-2 -6
Now the matrix m is:
 0  0 -5 -3
 0  0  1  0
 6 -3  0  9
 6  6  3  9
See also
class Block, block(Index,Index,Index,Index)

◆ topLeftCorner() [2/4]

template<typename Derived>
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > topLeftCorner ( ) const
inline

This is the const version of topLeftCorner<int, int>().

◆ topLeftCorner() [3/4]

template<typename Derived>
Block< Derived > topLeftCorner ( Index cRows,
Index cCols )
inline
Returns
a dynamic-size expression of a top-left corner of *this.
Parameters
cRowsthe number of rows in the corner
cColsthe number of columns in the corner

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.topLeftCorner(2, 2):" << endl;
cout << m.topLeftCorner(2, 2) << endl;
m.topLeftCorner(2, 2).setZero();
cout << "Now the matrix m is:" << endl << m << endl;

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.topLeftCorner(2, 2):
 7  9
-2 -6
Now the matrix m is:
 0  0 -5 -3
 0  0  1  0
 6 -3  0  9
 6  6  3  9
See also
class Block, block(Index,Index,Index,Index)

◆ topLeftCorner() [4/4]

template<typename Derived>
const Block< const Derived > topLeftCorner ( Index cRows,
Index cCols ) const
inline

This is the const version of topLeftCorner(Index, Index).

◆ topRightCorner() [1/4]

template<typename Derived>
template<int CRows, int CCols>
Block< Derived, CRows, CCols > topRightCorner ( )
inline
Returns
an expression of a fixed-size top-right corner of *this.

The template parameters CRows and CCols are the number of rows and columns in the corner.

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.topRightCorner<2,2>():" << endl;
cout << m.topRightCorner<2,2>() << endl;
cout << "Now the matrix m is:" << endl << m << endl;
Block< Matrix< _Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols > > topRightCorner(Index cRows, Index cCols)
Definition DenseBase.h:79

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.topRightCorner<2,2>():
-5 -3
 1  0
Now the matrix m is:
 7  9  0  0
-2 -6  0  0
 6 -3  0  9
 6  6  3  9
See also
class Block, block(Index,Index,Index,Index)

◆ topRightCorner() [2/4]

template<typename Derived>
template<int CRows, int CCols>
const Block< const Derived, CRows, CCols > topRightCorner ( ) const
inline

This is the const version of topRightCorner<int, int>().

◆ topRightCorner() [3/4]

template<typename Derived>
Block< Derived > topRightCorner ( Index cRows,
Index cCols )
inline
Returns
a dynamic-size expression of a top-right corner of *this.
Parameters
cRowsthe number of rows in the corner
cColsthe number of columns in the corner

Example:

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.topRightCorner(2, 2):" << endl;
cout << m.topRightCorner(2, 2) << endl;
m.topRightCorner(2, 2).setZero();
cout << "Now the matrix m is:" << endl << m << endl;

Output:

Here is the matrix m:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is m.topRightCorner(2, 2):
-5 -3
 1  0
Now the matrix m is:
 7  9  0  0
-2 -6  0  0
 6 -3  0  9
 6  6  3  9
See also
class Block, block(Index,Index,Index,Index)

◆ topRightCorner() [4/4]

template<typename Derived>
const Block< const Derived > topRightCorner ( Index cRows,
Index cCols ) const
inline

This is the const version of topRightCorner(Index, Index).

◆ topRows() [1/4]

template<typename Derived>
template<int N>
NRowsBlockXpr< N >::Type topRows ( )
inline
Returns
a block consisting of the top rows of *this.
Template Parameters
Nthe number of rows in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.topRows<2>():" << endl;
cout << a.topRows<2>() << endl;
a.topRows<2>().setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.topRows<2>():
 7  9 -5 -3
-2 -6  1  0
Now the array a is:
 0  0  0  0
 0  0  0  0
 6 -3  0  9
 6  6  3  9
See also
class Block, block(Index,Index,Index,Index)

◆ topRows() [2/4]

template<typename Derived>
template<int N>
ConstNRowsBlockXpr< N >::Type topRows ( ) const
inline

This is the const version of topRows<int>().

◆ topRows() [3/4]

template<typename Derived>
RowsBlockXpr topRows ( Index n)
inline
Returns
a block consisting of the top rows of *this.
Parameters
nthe number of rows in the block

Example:

Array44i a = Array44i::Random();
cout << "Here is the array a:" << endl << a << endl;
cout << "Here is a.topRows(2):" << endl;
cout << a.topRows(2) << endl;
a.topRows(2).setZero();
cout << "Now the array a is:" << endl << a << endl;

Output:

Here is the array a:
 7  9 -5 -3
-2 -6  1  0
 6 -3  0  9
 6  6  3  9
Here is a.topRows(2):
 7  9 -5 -3
-2 -6  1  0
Now the array a is:
 0  0  0  0
 0  0  0  0
 6 -3  0  9
 6  6  3  9
See also
class Block, block(Index,Index,Index,Index)

References DenseBase().

◆ topRows() [4/4]

template<typename Derived>
ConstRowsBlockXpr topRows ( Index n) const
inline

This is the const version of topRows(Index).

References DenseBase().

◆ transpose() [1/2]

template<typename Derived>
Transpose< Derived > transpose ( )
inline
Returns
an expression of the transpose of *this.

Example:

Matrix2i m = Matrix2i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is the transpose of m:" << endl << m.transpose() << endl;
cout << "Here is the coefficient (1,0) in the transpose of m:" << endl
<< m.transpose()(1,0) << endl;
cout << "Let us overwrite this coefficient with the value 0." << endl;
m.transpose()(1,0) = 0;
cout << "Now the matrix m is:" << endl << m << endl;

Output:

Here is the matrix m:
7 6
-2 6
Here is the transpose of m:
 7 -2
 6  6
Here is the coefficient (1,0) in the transpose of m:
6
Let us overwrite this coefficient with the value 0.
Now the matrix m is:
7 0
-2 6
Warning
If you want to replace a matrix by its own transpose, do NOT do this:
m = m.transpose(); // bug!!! caused by aliasing effect
Instead, use the transposeInPlace() method:
m.transposeInPlace();
which gives Eigen good opportunities for optimization, or alternatively you can also do:
m = m.transpose().eval();
See also
transposeInPlace(), adjoint()

Referenced by MatrixBase< Derived >::adjoint().

◆ transpose() [2/2]

template<typename Derived>
const DenseBase< Derived >::ConstTransposeReturnType transpose ( ) const
inline

This is the const version of transpose().

Make sure you read the warning for transpose() !

See also
transposeInPlace(), adjoint()

◆ transposeInPlace()

template<typename Derived>
void transposeInPlace ( )
inline

This is the "in place" version of transpose(): it replaces *this by its own transpose. Thus, doing

m.transposeInPlace();

has the same effect on m as doing

m = m.transpose().eval();

and is faster and also safer because in the latter line of code, forgetting the eval() results in a bug caused by aliasing.

Notice however that this method is only useful if you want to replace a matrix by its own transpose. If you just need the transpose of a matrix, use transpose().

Note
if the matrix is not square, then *this must be a resizable matrix.
See also
transpose(), adjoint(), adjointInPlace()

◆ value()

template<typename Derived>
CoeffReturnType value ( ) const
inline
Returns
the unique coefficient of a 1x1 expression

Referenced by bottomRows(), bottomRows(), Constant(), Constant(), Constant(), fill(), isApproxToConstant(), and middleRows().

◆ visit()

template<typename Derived>
template<typename Visitor>
void visit ( Visitor & visitor) const

Applies the visitor visitor to the whole coefficients of the matrix or vector.

The template parameter Visitor is the type of the visitor and provides the following interface:

struct MyVisitor {
// called for the first coefficient
void init(const Scalar& value, Index i, Index j);
// called for all other coefficients
void operator() (const Scalar& value, Index i, Index j);
};
internal::traits< Derived >::Index Index
The type of indices.
Definition DenseBase.h:51
CoeffReturnType value() const
Definition DenseBase.h:434
Note
compared to one or two for loops, visitors offer automatic unrolling for small fixed size matrix.
See also
minCoeff(Index*,Index*), maxCoeff(Index*,Index*), DenseBase::redux()

References CoeffReadCost, and SizeAtCompileTime.

Referenced by maxCoeff(), maxCoeff(), minCoeff(), and minCoeff().

◆ Zero() [1/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Zero ( )
inlinestatic
Returns
an expression of a fixed-size zero matrix or vector.

This variant is only for fixed-size MatrixBase types. For dynamic-size types, you need to use the variants taking size arguments.

Example:

cout << Matrix2d::Zero() << endl;
cout << RowVector4i::Zero() << endl;

Output:

0 0
0 0
0 0 0 0
See also
Zero(Index), Zero(Index,Index)

References Constant().

◆ Zero() [2/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Zero ( Index rows,
Index cols )
inlinestatic
Returns
an expression of a zero matrix.

The parameters rows and cols are the number of rows and of columns of the returned matrix. Must be compatible with this MatrixBase type.

This variant is meant to be used for dynamic-size matrix types. For fixed-size types, it is redundant to pass rows and cols as arguments, so Zero() should be used instead.

Example:

cout << MatrixXi::Zero(2,3) << endl;

Output:

0 0 0
0 0 0
See also
Zero(), Zero(Index)

References Constant().

◆ Zero() [3/3]

template<typename Derived>
const DenseBase< Derived >::ConstantReturnType Zero ( Index size)
inlinestatic
Returns
an expression of a zero vector.

The parameter size is the size of the returned vector. Must be compatible with this MatrixBase type.

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.

This variant is meant to be used for dynamic-size vector types. For fixed-size types, it is redundant to pass size as argument, so Zero() should be used instead.

Example:

cout << RowVectorXi::Zero(4) << endl;
cout << VectorXf::Zero(2) << endl;

Output:

0 0 0 0
0
0
See also
Zero(), Zero(Index,Index)

References Constant().

Friends And Related Symbol Documentation

◆ operator<<()

template<typename Derived>
std::ostream & operator<< ( std::ostream & s,
const DenseBase< Derived > & m )
related

Outputs the matrix, to the given stream.

If you wish to print the matrix with a format different than the default, use DenseBase::format().

It is also possible to change the default format by defining EIGEN_DEFAULT_IO_FORMAT before including Eigen headers. If not defined, this will automatically be defined to Eigen::IOFormat(), that is the Eigen::IOFormat with default parameters.

See also
DenseBase::format()

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