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Eigen  3.2.5
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Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, IndexType > Class Template Reference
[Core module]

Represents a sequence of transpositions (row/column interchange). More...

Inherits Eigen::TranspositionsBase< Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, IndexType > >.

List of all members.

Public Member Functions

const Index & coeff (Index i) const
Index & coeffRef (Index i)
IndicesType & indices ()
const IndicesType & indices () const
Transpose< TranspositionsBase > inverse () const
Index & operator() (Index i)
const Index & operator() (Index i) const
template<typename OtherDerived >
Transpositionsoperator= (const TranspositionsBase< OtherDerived > &other)
Index & operator[] (Index i)
const Index & operator[] (Index i) const
void resize (int newSize)
void setIdentity ()
Index size () const
Transpose< TranspositionsBase > transpose () const
 Transpositions (Index size)
template<typename Other >
 Transpositions (const MatrixBase< Other > &a_indices)
template<typename OtherDerived >
 Transpositions (const TranspositionsBase< OtherDerived > &other)

Detailed Description

template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename IndexType>
class Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, IndexType >

Represents a sequence of transpositions (row/column interchange).

Parameters:
SizeAtCompileTime the number of transpositions, or Dynamic
MaxSizeAtCompileTime the maximum number of transpositions, or Dynamic. This optional parameter defaults to SizeAtCompileTime. Most of the time, you should not have to specify it.

This class represents a permutation transformation as a sequence of n transpositions $[T_{n-1} \ldots T_{i} \ldots T_{0}]$. It is internally stored as a vector of integers indices. Each transposition $ T_{i} $ applied on the left of a matrix ($ T_{i} M$) interchanges the rows i and indices[i] of the matrix M. A transposition applied on the right (e.g., $ M T_{i}$) yields a column interchange.

Compared to the class PermutationMatrix, such a sequence of transpositions is what is computed during a decomposition with pivoting, and it is faster when applying the permutation in-place.

To apply a sequence of transpositions to a matrix, simply use the operator * as in the following example:

 Transpositions tr;
 MatrixXf mat;
 mat = tr * mat;

In this example, we detect that the matrix appears on both side, and so the transpositions are applied in-place without any temporary or extra copy.

See also:
class PermutationMatrix

Constructor & Destructor Documentation

Transpositions ( const TranspositionsBase< OtherDerived > &  other  )  [inline]

Copy constructor.

Transpositions ( const MatrixBase< Other > &  a_indices  )  [inline, explicit]

Generic constructor from expression of the transposition indices.

Transpositions ( Index  size  )  [inline]

Constructs an uninitialized permutation matrix of given size.


Member Function Documentation

const Index& coeff ( Index  i  )  const [inline, inherited]

Direct access to the underlying index vector

Index& coeffRef ( Index  i  )  [inline, inherited]

Direct access to the underlying index vector

IndicesType& indices (  )  [inline]
Returns:
a reference to the stored array representing the transpositions.
const IndicesType& indices (  )  const [inline]

const version of indices().

Transpose<TranspositionsBase> inverse (  )  const [inline, inherited]
Returns:
the inverse transformation
Index& operator() ( Index  i  )  [inline, inherited]

Direct access to the underlying index vector

const Index& operator() ( Index  i  )  const [inline, inherited]

Direct access to the underlying index vector

Transpositions& operator= ( const TranspositionsBase< OtherDerived > &  other  )  [inline]

Copies the other transpositions into *this

Referenced by Transpositions< RowsAtCompileTime, MaxRowsAtCompileTime >::operator=().

Index& operator[] ( Index  i  )  [inline, inherited]

Direct access to the underlying index vector

const Index& operator[] ( Index  i  )  const [inline, inherited]

Direct access to the underlying index vector

void resize ( int  newSize  )  [inline, inherited]

Resizes to given size.

void setIdentity (  )  [inline, inherited]

Sets *this to represents an identity transformation

Index size (  )  const [inline, inherited]
Returns:
the number of transpositions
Transpose<TranspositionsBase> transpose (  )  const [inline, inherited]
Returns:
the tranpose transformation

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