Eigen  3.4.90 (git rev 67eeba6e720c5745abc77ae6c92ce0a44aa7b7ae)
Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ > Class Template Reference

## Detailed Description

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

Represents a sequence of transpositions (row/column interchange)

Template 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;
mat = tr * mat;
Matrix< float, Dynamic, Dynamic > MatrixXf
Dynamic×Dynamic matrix of type float.
Definition: Matrix.h:500

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.

class PermutationMatrix

Inherits Eigen::TranspositionsBase< Derived >.

## Public Member Functions

IndicesType & indices ()

const IndicesType & indices () const

template<typename OtherDerived >
Transpositionsoperator= (const TranspositionsBase< OtherDerived > &other)

template<typename Other >
Transpositions (const MatrixBase< Other > &indices)

template<typename OtherDerived >
Transpositions (const TranspositionsBase< OtherDerived > &other)

Transpositions (Index size)

## ◆ Transpositions() [1/3]

template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename StorageIndex_ >
template<typename OtherDerived >
 Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ >::Transpositions ( const TranspositionsBase< OtherDerived > & other )
inline

Copy constructor.

## ◆ Transpositions() [2/3]

template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename StorageIndex_ >
template<typename Other >
 Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ >::Transpositions ( const MatrixBase< Other > & indices )
inlineexplicit

Generic constructor from expression of the transposition indices.

## ◆ Transpositions() [3/3]

template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename StorageIndex_ >
 Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ >::Transpositions ( Index size )
inline

Constructs an uninitialized permutation matrix of given size.

## ◆ indices() [1/2]

template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename StorageIndex_ >
 IndicesType& Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ >::indices ( )
inline
Returns
a reference to the stored array representing the transpositions.

## ◆ indices() [2/2]

template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename StorageIndex_ >
 const IndicesType& Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ >::indices ( ) const
inline

const version of indices().

## ◆ operator=()

template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename StorageIndex_ >
template<typename OtherDerived >
 Transpositions& Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ >::operator= ( const TranspositionsBase< OtherDerived > & other )
inline

Copies the other transpositions into *this

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