Define non-const operator() in Reverse; enable test for this.

Introduction of DenseCoeffBase (revision bfdc1c4973
) meant that non-const
operator() is only defined if DirectAccess is set. This caused the line
"m.reverse()(1,0) = 4;" in MatrixBase_reverse.cpp to fail at compile-time.
Not sure this is correct solution; perhaps we should disallow this? Or make
Reverse DirectAccess with a negative stride - would that break something?

Eigen/src/Array/Reverse.h

@@ -84,6 +84,10 @@ template<typename MatrixType, int Direction> class Reverse
     EIGEN_DENSE_PUBLIC_INTERFACE(Reverse)
     using Base::IsRowMajor;
 
+    // next line is necessary because otherwise const version of operator()
+    // is hidden by non-const version defined in this file
+    using Base::operator(); 
+
   protected:
     enum {
       PacketSize = ei_packet_traits<Scalar>::size,
@@ -106,6 +110,12 @@ template<typename MatrixType, int Direction> class Reverse
     inline Index rows() const { return m_matrix.rows(); }
     inline Index cols() const { return m_matrix.cols(); }
 
+    inline Scalar& operator()(Index row, Index col)
+    {
+      ei_assert(row >= 0 && row < rows() && col >= 0 && col < cols());
+      return coeffRef(row, col);
+    }
+
     inline Scalar& coeffRef(Index row, Index col)
     {
       return m_matrix.const_cast_derived().coeffRef(ReverseRow ? m_matrix.rows() - row - 1 : row,
@@ -128,6 +138,12 @@ template<typename MatrixType, int Direction> class Reverse
       return m_matrix.const_cast_derived().coeffRef(m_matrix.size() - index - 1);
     }
 
+    inline Scalar& operator()(Index index)
+    {
+      ei_assert(index >= 0 && index < m_matrix.size());
+      return coeffRef(index);
+    }
+
     template<int LoadMode>
     inline const PacketScalar packet(Index row, Index col) const
     {

Eigen/src/Array/VectorwiseOp.h

@@ -380,8 +380,8 @@ template<typename ExpressionType, int Direction> class VectorwiseOp
     /** \returns a matrix expression
       * where each column (or row) are reversed.
       *
-      * Example: \include PartialRedux_reverse.cpp
-      * Output: \verbinclude PartialRedux_reverse.out
+      * Example: \include VectorWise_reverse.cpp
+      * Output: \verbinclude VectorWise_reverse.out
       *
       * \sa DenseBase::reverse() */
     const Reverse<ExpressionType, Direction> reverse() const