eigen/Eigen/src/Core/Transpose.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either 
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of 
// the License, or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public 
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.

#ifndef EIGEN_TRANSPOSE_H
#define EIGEN_TRANSPOSE_H

/** \class Transpose
  *
  * \brief Expression of the transpose of a matrix
  *
  * \param MatrixType the type of the object of which we are taking the transpose
  *
  * This class represents an expression of the transpose of a matrix.
  * It is the return type of MatrixBase::transpose() and MatrixBase::adjoint()
  * and most of the time this is the only way it is used.
  *
  * \sa MatrixBase::transpose(), MatrixBase::adjoint()
  */
template<typename MatrixType> class Transpose
  : public MatrixBase<typename MatrixType::Scalar, Transpose<MatrixType> >
{
  public:
    typedef typename MatrixType::Scalar Scalar;
    typedef typename MatrixType::Ref MatRef;
    friend class MatrixBase<Scalar, Transpose>;
    typedef MatrixBase<Scalar, Transpose> Base;
    
    Transpose(const MatRef& matrix) : m_matrix(matrix) {}
    
    EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Transpose)
    
  private:
    enum {
      RowsAtCompileTime = MatrixType::Traits::ColsAtCompileTime,
      ColsAtCompileTime = MatrixType::Traits::RowsAtCompileTime,
      MaxRowsAtCompileTime = MatrixType::Traits::MaxColsAtCompileTime,
      MaxColsAtCompileTime = MatrixType::Traits::MaxRowsAtCompileTime
    };

    const Transpose& _ref() const { return *this; }
    int _rows() const { return m_matrix.cols(); }
    int _cols() const { return m_matrix.rows(); }
    
    Scalar& _coeffRef(int row, int col)
    {
      return m_matrix.coeffRef(col, row);
    }
    
    Scalar _coeff(int row, int col) const
    {
      return m_matrix.coeff(col, row);
    }
    
  protected:
    MatRef m_matrix;
};

/** \returns an expression of the transpose of *this.
  *
  * Example: \include MatrixBase_transpose.cpp
  * Output: \verbinclude MatrixBase_transpose.out
  *
  * \sa adjoint(), class DiagonalCoeffs */
template<typename Scalar, typename Derived>
Transpose<Derived>
MatrixBase<Scalar, Derived>::transpose()
{
  return Transpose<Derived>(ref());
}

/** This is the const version of transpose(). \sa adjoint() */
template<typename Scalar, typename Derived>
const Transpose<Derived>
MatrixBase<Scalar, Derived>::transpose() const
{
  return Transpose<Derived>(ref());
}

/** \returns an expression of the adjoint (i.e. conjugate transpose) of *this.
  *
  * Example: \include MatrixBase_adjoint.cpp
  * Output: \verbinclude MatrixBase_adjoint.out
  *
  * \sa transpose(), conjugate(), class Transpose, class ConjugateOp */
template<typename Scalar, typename Derived>
const Transpose<CwiseUnaryOp<ConjugateOp, Derived> >
MatrixBase<Scalar, Derived>::adjoint() const
{
  return conjugate().transpose();
}

#endif // EIGEN_TRANSPOSE_H