Eigen  3.3.7
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 . It is internally stored as a vector of integers `indices`. Each transposition applied on the left of a matrix ( ) interchanges the rows `i` and `indices`[i] of the matrix `M`. A transposition applied on the right (e.g., ) 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;

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

const IndicesType & indices () const

IndicesType & indices ()

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

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

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

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>
 const IndicesType& Eigen::Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, _StorageIndex >::indices ( ) const
inline

const version of indices().

## ◆ indices() [2/2]

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.

## ◆ 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: