apply Ricard patch for Reverse with minor modifications

2 files changed, 254 insertions, 1 deletions

diff --git a/Eigen/src/Array/PartialRedux.h b/Eigen/src/Array/PartialRedux.h
index 96c13ca2b..d2813cfd7 100644
--- a/Eigen/src/Array/PartialRedux.h
+++ b/Eigen/src/Array/PartialRedux.h
@@ -257,7 +257,21 @@ template<typename ExpressionType, int Direction> class PartialRedux
       * \sa MatrixBase::count() */
     const PartialReduxExpr<ExpressionType, ei_member_count<int>, Direction> count() const
     { return _expression(); }
-
+    
+    
+    /** \returns a matrix expression
+      * where each column (or row) are reversed.
+      *
+      * Example: \include PartialRedux_reverse.cpp
+      * Output: \verbinclude PartialRedux_reverse.out
+      *
+      * \sa MatrixBase::reverse() */
+    const Reverse<ExpressionType, Direction> reverse() const
+    {
+      return Reverse<ExpressionType, Direction>( _expression() );
+    }
+  
+    
     /** \returns a 3x3 matrix expression of the cross product
       * of each column or row of the referenced expression with the \a other vector.
       *
diff --git a/Eigen/src/Array/Reverse.h b/Eigen/src/Array/Reverse.h
new file mode 100644
index 000000000..16740b4bd
--- /dev/null
+++ b/Eigen/src/Array/Reverse.h
@@ -0,0 +1,239 @@
+// 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.benoit.1@gmail.com>
+// Copyright (C) 2009 Ricard Marxer <email@ricardmarxer.com>
+//
+// 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_REVERSE_H
+#define EIGEN_REVERSE_H
+
+#include <iostream>
+using namespace std;
+
+/** \array_module \ingroup Array
+  *
+  * \class Reverse
+  *
+  * \brief Expression of the reverse of a vector or matrix
+  *
+  * \param MatrixType the type of the object of which we are taking the reverse
+  *
+  * This class represents an expression of the reverse of a vector.
+  * It is the return type of MatrixBase::reverse() and PartialRedux::reverse()
+  * and most of the time this is the only way it is used.
+  *
+  * \sa MatrixBase::reverse(), PartialRedux::reverse()
+  */
+template<typename MatrixType, int Direction>
+struct ei_traits<Reverse<MatrixType, Direction> >
+{
+  typedef typename MatrixType::Scalar Scalar;
+  typedef typename ei_nested<MatrixType>::type MatrixTypeNested;
+  typedef typename ei_unref<MatrixTypeNested>::type _MatrixTypeNested;
+  enum {
+    RowsAtCompileTime = MatrixType::RowsAtCompileTime,
+    ColsAtCompileTime = MatrixType::ColsAtCompileTime,
+    MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
+    MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime,
+
+    // TODO: check how to correctly set the new flags
+    Flags = ((int(_MatrixTypeNested::Flags) & HereditaryBits)
+          & ~(LowerTriangularBit | UpperTriangularBit))
+          | (int(_MatrixTypeNested::Flags)&UpperTriangularBit ? LowerTriangularBit : 0)
+          | (int(_MatrixTypeNested::Flags)&LowerTriangularBit ? UpperTriangularBit : 0),
+
+    // TODO: should add two add costs (due to the -1) or only one, and add the cost of calling .rows() and .cols()
+    CoeffReadCost = _MatrixTypeNested::CoeffReadCost
+  };
+};
+
+template<typename MatrixType, int Direction> class Reverse
+  : public MatrixBase<Reverse<MatrixType, Direction> >
+{
+  public:
+
+    EIGEN_GENERIC_PUBLIC_INTERFACE(Reverse)
+
+    inline Reverse(const MatrixType& matrix) : m_matrix(matrix) { }
+
+    EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Reverse)
+
+    inline int rows() const { return m_matrix.rows(); }
+    inline int cols() const { return m_matrix.cols(); }
+
+    inline Scalar& coeffRef(int row, int col)
+    {
+      return m_matrix.const_cast_derived().coeffRef(((Direction == Vertical) || (Direction == BothDirections)) ? m_matrix.rows() - row - 1 : row,
+                                                    ((Direction == Horizontal) || (Direction == BothDirections)) ? m_matrix.cols() - col - 1 : col);
+    }
+
+    inline const Scalar coeff(int row, int col) const
+    {
+      return m_matrix.coeff(((Direction == Vertical) || (Direction == BothDirections)) ? m_matrix.rows() - row - 1 : row,
+                            ((Direction == Horizontal) || (Direction == BothDirections)) ? m_matrix.cols() - col - 1 : col);
+    }
+
+    /* could be removed */
+    /*
+    inline const Scalar coeff(int index) const
+    {
+      switch ( Direction )
+        {
+        case Vertical:
+          return m_matrix.coeff( index + m_matrix.rows() - 2 * (index % m_matrix.rows()) - 1 );
+          break;
+
+        case Horizontal:
+          return m_matrix.coeff( (index % m_matrix.rows()) + (m_matrix.cols() - 1 - index/m_matrix.rows()) * m_matrix.rows() );
+          break;
+
+        case BothDirections:
+          return m_matrix.coeff((m_matrix.rows() * m_matrix.cols()) - index - 1);
+          break;
+        }
+
+    }
+
+    inline Scalar& coeffRef(int index)
+    {
+      switch ( Direction )
+        {
+        case Vertical:
+          return m_matrix.const_cast_derived().coeffRef( index + m_matrix.rows() - 2 * (index % m_matrix.rows()) - 1 );
+          break;
+
+        case Horizontal:
+          return m_matrix.const_cast_derived().coeffRef( (index % m_matrix.rows()) + (m_matrix.cols() - 1 - index/m_matrix.rows()) * m_matrix.rows() );
+          break;
+
+        case BothDirections:
+          return m_matrix.const_cast_derived().coeffRef( (m_matrix.rows() * m_matrix.cols()) - index - 1 );
+          break;
+        }
+    }
+    */
+
+    /* the following is not ready yet */
+    /*
+    // TODO: We must reverse the packet reading and writing, which is currently not done here, I think
+    template<int LoadMode>
+    inline const PacketScalar packet(int row, int col) const
+    {
+      return m_matrix.template packet<LoadMode>(((Direction == Vertical) || (Direction == BothDirections)) ? m_matrix.rows() - row - 1 : row,
+                                                ((Direction == Horizontal) || (Direction == BothDirections)) ? m_matrix.cols() - col - 1 : col);
+    }
+
+    template<int LoadMode>
+    inline void writePacket(int row, int col, const PacketScalar& x)
+    {
+      m_matrix.const_cast_derived().template writePacket<LoadMode>(((Direction == Vertical) || (Direction == BothDirections)) ? m_matrix.rows() - row - 1 : row,
+                                                                   ((Direction == Horizontal) || (Direction == BothDirections)) ? m_matrix.cols() - col - 1 : col,
+                                                                   x);
+    }
+
+    template<int LoadMode>
+    inline const PacketScalar packet(int index) const
+    {
+      switch ( Direction )
+        {
+        case Vertical:
+          return m_matrix.template packet<LoadMode>( index + m_matrix.rows() - 2 * (index % m_matrix.rows()) - 1 );
+          break;
+
+        case Horizontal:
+          return m_matrix.template packet<LoadMode>( (index % m_matrix.rows()) + (m_matrix.cols() - 1 - index/m_matrix.rows()) * m_matrix.rows() );
+          break;
+
+        case BothDirections:
+          return m_matrix.template packet<LoadMode>( (m_matrix.rows() * m_matrix.cols()) - index - 1 );
+          break;
+        }
+    }
+    */
+
+    /* could be removed */
+    /*
+    template<int LoadMode>
+    inline void writePacket(int index, const PacketScalar& x)
+    {
+      switch ( Direction )
+        {
+        case Vertical:
+          return m_matrix.const_cast_derived().template packet<LoadMode>( index + m_matrix.rows() - 2 * (index % m_matrix.rows()) - 1, x );
+          break;
+
+        case Horizontal:
+          return m_matrix.const_cast_derived().template packet<LoadMode>( (index % m_matrix.rows()) + (m_matrix.cols() - 1 - index/m_matrix.rows()) * m_matrix.rows(), x );
+          break;
+
+        case BothDirections:
+          return m_matrix.const_cast_derived().template packet<LoadMode>( (m_matrix.rows() * m_matrix.cols()) - index - 1, x );
+          break;
+        }
+    }
+    */
+
+  protected:
+    const typename MatrixType::Nested m_matrix;
+};
+
+/** \returns an expression of the reverse of *this.
+  *
+  * Example: \include MatrixBase_reverse.cpp
+  * Output: \verbinclude MatrixBase_reverse.out
+  *
+  */
+template<typename Derived>
+inline Reverse<Derived, BothDirections>
+MatrixBase<Derived>::reverse()
+{
+  return derived();
+}
+
+/** This is the const version of reverse(). */
+template<typename Derived>
+inline const Reverse<Derived, BothDirections>
+MatrixBase<Derived>::reverse() const
+{
+  return derived();
+}
+
+/** This is the "in place" version of reverse: it reverses \c *this.
+  *
+  * In most cases it is probably better to simply use the reversed expression
+  * of a matrix. However, when reversing the matrix data itself is really needed,
+  * then this "in-place" version is probably the right choice because it provides
+  * the following additional features:
+  *  - less error prone: doing the same operation with .reverse() requires special care:
+  *    \code m = m.reverse().eval(); \endcode
+  *  - no temporary object is created (currently there is one created but could be avoided using swap)
+  *  - it allows future optimizations (cache friendliness, etc.)
+  *
+  * \sa reverse() */
+template<typename Derived>
+inline void MatrixBase<Derived>::reverseInPlace()
+{
+  derived() = derived().reverse().eval();
+}
+
+
+#endif // EIGEN_REVERSE_H