Public Member Functions
Transpositions< SizeAtCompileTime, MaxSizeAtCompileTime, IndexType > Class Template Reference

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

Inherits TranspositionsBase< Derived >.

List of all members.

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)
- Public Member Functions inherited from TranspositionsBase< Derived >
const Index & coeff (Index i) const
Index & coeffRef (Index i)
const IndicesType & indices () const
IndicesType & indices ()
Transpose< TranspositionsBase > inverse () const
const Index & operator() (Index i) const
Index & operator() (Index i)
template<typename OtherDerived >
Derived & operator= (const TranspositionsBase< OtherDerived > &other)
const Index & operator[] (Index i) const
Index & operator[] (Index i)
void resize (int size)
void setIdentity ()
Index size () const
Transpose< TranspositionsBase > transpose () const

Detailed Description

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

Represents a sequence of transpositions (row/column interchange)

Parameters:
SizeAtCompileTimethe number of transpositions, or Dynamic
MaxSizeAtCompileTimethe 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 > &  indices)
inlineexplicit

Generic constructor from expression of the transposition indices.

Transpositions ( Index  size)
inline

Constructs an uninitialized permutation matrix of given size.


Member Function Documentation

const IndicesType& indices ( ) const
inline

const version of indices().

IndicesType& indices ( )
inline
Returns:
a reference to the stored array representing the transpositions.
Transpositions& operator= ( const TranspositionsBase< OtherDerived > &  other)
inline

Copies the other transpositions into *this


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