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

Introduction of DenseCoeffBase (revision bfdc1c49730c79e6058ba1506628341559670c25
) 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

test/array_reverse.cpp

@@ -103,47 +103,6 @@ template<typename MatrixType> void reverse(const MatrixType& m)
     }
   }
 
-  /*
-  cout << "m1:" << endl << m1 << endl;
-  cout << "m1c_reversed:" << endl << m1c_reversed << endl;
-
-  cout << "----------------" << endl;
-
-  for ( int i=0; i< rows*cols; i++){
-    cout << m1c_reversed.coeff(i) << endl;
-  }
-
-  cout << "----------------" << endl;
-
-  for ( int i=0; i< rows*cols; i++){
-    cout << m1c_reversed.colwise().reverse().coeff(i) << endl;
-  }
-
-  cout << "================" << endl;
-
-  cout << "m1.coeff( ind ): " << m1.coeff( ind ) << endl;
-  cout << "m1c_reversed.colwise().reverse().coeff( ind ): " << m1c_reversed.colwise().reverse().coeff( ind ) << endl;
-  */
-
-  //MatrixType m1r_reversed = m1.rowwise().reverse();
-  //VERIFY_IS_APPROX( m1r_reversed.rowwise().reverse().coeff( ind ), m1.coeff( ind ) );
-
-  /*
-  cout << "m1" << endl << m1 << endl;
-  cout << "m1 using coeff(int index)" << endl;
-  for ( int i = 0; i < rows*cols; i++) {
-    cout << m1.coeff(i) << " ";
-  }
-  cout << endl;
-
-  cout << "m1.transpose()" << endl << m1.transpose() << endl;
-  cout << "m1.transpose() using coeff(int index)" << endl;
-  for ( int i = 0; i < rows*cols; i++) {
-    cout << m1.transpose().coeff(i) << " ";
-  }
-  cout << endl;
-  */
-  /*
   Scalar x = ei_random<Scalar>();
 
   int r = ei_random<int>(0, rows-1),
@@ -152,6 +111,7 @@ template<typename MatrixType> void reverse(const MatrixType& m)
   m1.reverse()(r, c) = x;
   VERIFY_IS_APPROX(x, m1(rows - 1 - r, cols - 1 - c));
 
+  /*
   m1.colwise().reverse()(r, c) = x;
   VERIFY_IS_APPROX(x, m1(rows - 1 - r, c));