* Added a generic *redux* mini framework allowing custom redux operations

   as well as partial redux (vertical or horizontal redux).
   Includes shortcuts for: sum, minCoeff and maxCoeff.
   There is no shortcut for the partial redux.

 * Added a generic *visitor* mini framework. A visitor is a custom object
   sequentially applied on each coefficient with knowledge of its value and
   coordinates.
   It is currentlly used to implement minCoeff(int*,int*) and maxCoeff(int*,int*).
   findBiggestCoeff is now a shortcut for "this->cwiseAbs().maxCoeff(i,j)"

 * Added coeff-wise min and max.
 * fixed an issue with ei_pow(int,int) and gcc < 4.3 or ICC

9 files changed, 551 insertions, 145 deletions

diff --git a/Eigen/src/Core/AssociativeFunctors.h b/Eigen/src/Core/AssociativeFunctors.h
new file mode 100644
index 000000000..106549f75
--- /dev/null
+++ b/Eigen/src/Core/AssociativeFunctors.h
@@ -0,0 +1,64 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008 Gael Guennebaud <g.gael@free.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_ASSOCIATIVE_FUNCTORS_H
+#define EIGEN_ASSOCIATIVE_FUNCTORS_H
+
+/** \internal
+  * \brief Template functor to compute the sum of two scalars
+  *
+  * \sa class CwiseBinaryOp, MatrixBase::operator+, class PartialRedux, MatrixBase::sum()
+  */
+struct ei_scalar_sum_op EIGEN_EMPTY_STRUCT {
+    template<typename Scalar> Scalar operator() (const Scalar& a, const Scalar& b) const { return a + b; }
+};
+
+/** \internal
+  * \brief Template functor to compute the product of two scalars
+  *
+  * \sa class CwiseBinaryOp, MatrixBase::cwiseProduct(), class PartialRedux, MatrixBase::redux()
+  */
+struct ei_scalar_product_op EIGEN_EMPTY_STRUCT {
+    template<typename Scalar> Scalar operator() (const Scalar& a, const Scalar& b) const { return a * b; }
+};
+
+/** \internal
+  * \brief Template functor to compute the min of two scalars
+  *
+  * \sa class CwiseBinaryOp, MatrixBase::cwiseMin, class PartialRedux, MatrixBase::minCoeff()
+  */
+struct ei_scalar_min_op EIGEN_EMPTY_STRUCT {
+    template<typename Scalar> Scalar operator() (const Scalar& a, const Scalar& b) const { return ei_min(a, b); }
+};
+
+/** \internal
+  * \brief Template functor to compute the max of two scalars
+  *
+  * \sa class CwiseBinaryOp, MatrixBase::cwiseMax, class PartialRedux, MatrixBase::maxCoeff()
+  */
+struct ei_scalar_max_op EIGEN_EMPTY_STRUCT {
+    template<typename Scalar> Scalar operator() (const Scalar& a, const Scalar& b) const { return ei_max(a, b); }
+};
+
+#endif // EIGEN_ASSOCIATIVE_FUNCTORS_H
diff --git a/Eigen/src/Core/CwiseBinaryOp.h b/Eigen/src/Core/CwiseBinaryOp.h
index 131e98362..1ab759241 100644
--- a/Eigen/src/Core/CwiseBinaryOp.h
+++ b/Eigen/src/Core/CwiseBinaryOp.h
@@ -94,15 +94,6 @@ class CwiseBinaryOp : ei_no_assignment_operator,
 };
 
 /** \internal
-  * \brief Template functor to compute the sum of two scalars
-  *
-  * \sa class CwiseBinaryOp, MatrixBase::operator+
-  */
-struct ei_scalar_sum_op EIGEN_EMPTY_STRUCT {
-    template<typename Scalar> Scalar operator() (const Scalar& a, const Scalar& b) const { return a + b; }
-};
-
-/** \internal
   * \brief Template functor to compute the difference of two scalars
   *
   * \sa class CwiseBinaryOp, MatrixBase::operator-
@@ -112,15 +103,6 @@ struct ei_scalar_difference_op EIGEN_EMPTY_STRUCT {
 };
 
 /** \internal
-  * \brief Template functor to compute the product of two scalars
-  *
-  * \sa class CwiseBinaryOp, MatrixBase::cwiseProduct()
-  */
-struct ei_scalar_product_op EIGEN_EMPTY_STRUCT {
-    template<typename Scalar> Scalar operator() (const Scalar& a, const Scalar& b) const { return a * b; }
-};
-
-/** \internal
   * \brief Template functor to compute the quotient of two scalars
   *
   * \sa class CwiseBinaryOp, MatrixBase::cwiseQuotient()
@@ -203,6 +185,30 @@ MatrixBase<Derived>::cwiseQuotient(const MatrixBase<OtherDerived> &other) const
   return CwiseBinaryOp<ei_scalar_quotient_op, Derived, OtherDerived>(derived(), other.derived());
 }
 
+/** \returns an expression of the coefficient-wise min of *this and \a other
+  *
+  * \sa class CwiseBinaryOp
+  */
+template<typename Derived>
+template<typename OtherDerived>
+const CwiseBinaryOp<ei_scalar_min_op, Derived, OtherDerived>
+MatrixBase<Derived>::cwiseMin(const MatrixBase<OtherDerived> &other) const
+{
+  return CwiseBinaryOp<ei_scalar_min_op, Derived, OtherDerived>(derived(), other.derived());
+}
+
+/** \returns an expression of the coefficient-wise max of *this and \a other
+  *
+  * \sa class CwiseBinaryOp
+  */
+template<typename Derived>
+template<typename OtherDerived>
+const CwiseBinaryOp<ei_scalar_max_op, Derived, OtherDerived>
+MatrixBase<Derived>::cwiseMax(const MatrixBase<OtherDerived> &other) const
+{
+  return CwiseBinaryOp<ei_scalar_max_op, Derived, OtherDerived>(derived(), other.derived());
+}
+
 /** \returns an expression of a custom coefficient-wise operator \a func of *this and \a other
   *
   * The template parameter \a CustomBinaryOp is the type of the functor
diff --git a/Eigen/src/Core/ForwardDeclarations.h b/Eigen/src/Core/ForwardDeclarations.h
index 69b8cab7b..9e0bbe2e6 100644
--- a/Eigen/src/Core/ForwardDeclarations.h
+++ b/Eigen/src/Core/ForwardDeclarations.h
@@ -45,6 +45,7 @@ template<typename MatrixType> class Identity;
 template<typename MatrixType> class Map;
 template<typename Derived> class Eval;
 template<typename Derived> class EvalOMP;
+template<int Direction, typename UnaryOp, typename MatrixType> class PartialRedux;
 
 struct ei_scalar_sum_op;
 struct ei_scalar_difference_op;
@@ -62,6 +63,8 @@ struct ei_scalar_sin_op;
 template<typename Scalar> struct ei_scalar_pow_op;
 template<typename NewType> struct ei_scalar_cast_op;
 template<typename Scalar>  struct ei_scalar_multiple_op;
+struct ei_scalar_min_op;
+struct ei_scalar_max_op;
 
 template<typename T> struct ei_xpr_copy
 {
diff --git a/Eigen/src/Core/MathFunctions.h b/Eigen/src/Core/MathFunctions.h
index 13bd549f4..a1a54cc38 100644
--- a/Eigen/src/Core/MathFunctions.h
+++ b/Eigen/src/Core/MathFunctions.h
@@ -5,12 +5,12 @@
 //
 // 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 
+// 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 
+// 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
@@ -18,7 +18,7 @@
 // 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 
+// 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/>.
 
@@ -40,7 +40,11 @@ inline int ei_exp(int)  { assert(false); return 0; }
 inline int ei_log(int)  { assert(false); return 0; }
 inline int ei_sin(int)  { assert(false); return 0; }
 inline int ei_cos(int)  { assert(false); return 0; }
+#if (defined __ICC) || (defined __GNUC__ && (__GNUC__<4 || __GNUC_MINOR__<3))
+inline int ei_pow(int x, int y) { return int(std::pow(double(x), y)); }
+#else
 inline int ei_pow(int x, int y) { return std::pow(x, y); }
+#endif
 
 template<> inline int ei_random(int a, int b)
 {
diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index 95fc05b8e..f3be4977f 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -81,7 +81,7 @@ template<typename Derived> class MatrixBase
         /**< This is equal to the number of coefficients, i.e. the number of
           * rows times the number of columns, or to \a Dynamic if this is not
           * known at compile-time. \sa RowsAtCompileTime, ColsAtCompileTime */
-        
+
       MaxRowsAtCompileTime = ei_traits<Derived>::MaxRowsAtCompileTime,
         /**< This value is equal to the maximum possible number of rows that this expression
           * might have. If this expression might have an arbitrarily high number of rows,
@@ -245,13 +245,6 @@ template<typename Derived> class MatrixBase
     Derived& operator*=(const MatrixBase<OtherDerived>& other);
     //@}
 
-    /** \name Sums of coefficients
-      */
-    //@{
-    Scalar sum() const;
-    Scalar trace() const;
-    //@}
-
     /** \name Dot product and related notions
       * including vector norm, adjoint, transpose ...
       */
@@ -350,20 +343,7 @@ template<typename Derived> class MatrixBase
       * which has the biggest absolute value.
       */
     void findBiggestCoeff(int *row, int *col) const
-    {
-      RealScalar biggest = 0;
-      for(int j = 0; j < cols(); j++)
-        for(int i = 0; i < rows(); i++)
-        {
-          RealScalar x = ei_abs(coeff(i,j));
-          if(x > biggest)
-          {
-            biggest = x;
-            *row = i;
-            *col = j;
-          }
-        }
-    }
+    { (*this).cwiseAbs().maxCoeff(row, col); }
     //@}
 
     /// \name Special functions
@@ -396,6 +376,14 @@ template<typename Derived> class MatrixBase
     const CwiseBinaryOp<ei_scalar_quotient_op, Derived, OtherDerived>
     cwiseQuotient(const MatrixBase<OtherDerived> &other) const;
 
+    template<typename OtherDerived>
+    const CwiseBinaryOp<ei_scalar_min_op, Derived, OtherDerived>
+    cwiseMin(const MatrixBase<OtherDerived> &other) const;
+
+    template<typename OtherDerived>
+    const CwiseBinaryOp<ei_scalar_max_op, Derived, OtherDerived>
+    cwiseMax(const MatrixBase<OtherDerived> &other) const;
+
     const CwiseUnaryOp<ei_scalar_abs_op, Derived> cwiseAbs() const;
     const CwiseUnaryOp<ei_scalar_abs2_op, Derived> cwiseAbs2() const;
     const CwiseUnaryOp<ei_scalar_sqrt_op, Derived> cwiseSqrt() const;
@@ -414,6 +402,33 @@ template<typename Derived> class MatrixBase
     cwise(const MatrixBase<OtherDerived> &other, const CustomBinaryOp& func = CustomBinaryOp()) const;
     //@}
 
+    /// \name Redux and visitor
+    //@{
+    Scalar sum() const;
+    Scalar trace() const;
+
+    typename ei_traits<Derived>::Scalar minCoeff() const;
+    typename ei_traits<Derived>::Scalar maxCoeff() const;
+
+    typename ei_traits<Derived>::Scalar minCoeff(int* row, int* col = 0) const;
+    typename ei_traits<Derived>::Scalar maxCoeff(int* row, int* col = 0) const;
+
+    template<typename BinaryOp>
+    const PartialRedux<Vertical, BinaryOp, Derived>
+    verticalRedux(const BinaryOp& func) const;
+
+    template<typename BinaryOp>
+    const PartialRedux<Horizontal, BinaryOp, Derived>
+    horizontalRedux(const BinaryOp& func) const;
+
+    template<typename BinaryOp>
+    typename ei_result_of<BinaryOp(typename ei_traits<Derived>::Scalar)>::type
+    redux(const BinaryOp& func) const;
+
+    template<typename Visitor>
+    void visit(Visitor& func) const;
+    //@}
+
     /// \name Casting to the derived type
     //@{
     const Derived& derived() const { return *static_cast<const Derived*>(this); }
diff --git a/Eigen/src/Core/Redux.h b/Eigen/src/Core/Redux.h
new file mode 100644
index 000000000..fa1f0e652
--- /dev/null
+++ b/Eigen/src/Core/Redux.h
@@ -0,0 +1,232 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
+// 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_REDUX_H
+#define EIGEN_REDUX_H
+
+
+template<typename BinaryOp, typename Derived, int Start, int Length>
+struct ei_redux_unroller
+{
+  enum {
+    HalfLength = Length/2
+  };
+
+  typedef typename ei_result_of<BinaryOp(typename Derived::Scalar)>::type Scalar;
+
+  static Scalar run(const Derived &mat, const BinaryOp& func)
+  {
+    return func(
+      ei_redux_unroller<BinaryOp, Derived, Start, HalfLength>::run(mat, func),
+      ei_redux_unroller<BinaryOp, Derived, Start+HalfLength, Length - HalfLength>::run(mat, func));
+  }
+};
+
+template<typename BinaryOp, typename Derived, int Start>
+struct ei_redux_unroller<BinaryOp, Derived, Start, 1>
+{
+  enum {
+    col = Start / Derived::RowsAtCompileTime,
+    row = Start % Derived::RowsAtCompileTime
+  };
+
+  typedef typename ei_result_of<BinaryOp(typename Derived::Scalar)>::type Scalar;
+
+  static Scalar run(const Derived &mat, const BinaryOp &func)
+  {
+    return mat.coeff(row, col);
+  }
+};
+
+template<typename BinaryOp, typename Derived, int Start>
+struct ei_redux_unroller<BinaryOp, Derived, Start, Dynamic>
+{
+  typedef typename ei_result_of<BinaryOp(typename Derived::Scalar)>::type Scalar;
+  static Scalar run(const Derived&, const BinaryOp&) { return Scalar(); }
+};
+
+
+/** \class PartialRedux
+  *
+  * \brief Generic expression of a partially reduxed matrix
+  *
+  * \param Direction indicates the direction of the redux (Vertical or Horizontal)
+  * \param BinaryOp type of the binary functor implementing the operator (must be associative)
+  * \param MatrixType the type of the matrix we are applying the redux operation
+  *
+  * This class represents an expression of a partial redux operator of a matrix.
+  * It is the return type of MatrixBase::verticalRedux(), MatrixBase::horizontalRedux(),
+  * and most of the time this is the only way it is used.
+  *
+  * \sa class CwiseBinaryOp
+  */
+template<int Direction, typename BinaryOp, typename MatrixType>
+struct ei_traits<PartialRedux<Direction, BinaryOp, MatrixType> >
+{
+  typedef typename ei_result_of<
+                     BinaryOp(typename MatrixType::Scalar)
+                   >::type Scalar;
+  enum {
+    RowsAtCompileTime = Direction==Vertical   ? 1 : MatrixType::RowsAtCompileTime,
+    ColsAtCompileTime = Direction==Horizontal ? 1 : MatrixType::ColsAtCompileTime,
+    MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
+    MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
+  };
+};
+
+template<int Direction, typename BinaryOp, typename MatrixType>
+class PartialRedux : ei_no_assignment_operator,
+  public MatrixBase<PartialRedux<Direction, BinaryOp, MatrixType> >
+{
+  public:
+
+    EIGEN_GENERIC_PUBLIC_INTERFACE(PartialRedux)
+
+    PartialRedux(const MatrixType& mat, const BinaryOp& func = BinaryOp())
+      : m_matrix(mat), m_functor(func) {}
+
+  private:
+
+    int _rows() const { return (Direction==Vertical   ? 1 : m_matrix.rows()); }
+    int _cols() const { return (Direction==Horizontal ? 1 : m_matrix.cols()); }
+
+    Scalar _coeff(int i, int j) const
+    {
+      if (Direction==Vertical)
+        return this->col(j).redux(m_functor);
+      else
+        return this->row(i).redux(m_functor);
+    }
+
+  protected:
+    const typename MatrixType::XprCopy m_matrix;
+    const BinaryOp m_functor;
+};
+
+/** \returns a row vector expression of *this vertically reduxed by \a func
+  *
+  * The template parameter \a BinaryOp is the type of the functor
+  * of the custom redux operator. Note that func must be an associative operator.
+  *
+  * \sa class PartialRedux, MatrixBase::horizontalRedux()
+  */
+template<typename Derived>
+template<typename BinaryOp>
+const PartialRedux<Vertical, BinaryOp, Derived>
+MatrixBase<Derived>::verticalRedux(const BinaryOp& func) const
+{
+  return PartialRedux<Vertical, BinaryOp, Derived>(derived(), func);
+}
+
+/** \returns a row vector expression of *this horizontally reduxed by \a func
+  *
+  * The template parameter \a BinaryOp is the type of the functor
+  * of the custom redux operator. Note that func must be an associative operator.
+  *
+  * \sa class PartialRedux, MatrixBase::verticalRedux()
+  */
+template<typename Derived>
+template<typename BinaryOp>
+const PartialRedux<Horizontal, BinaryOp, Derived>
+MatrixBase<Derived>::horizontalRedux(const BinaryOp& func) const
+{
+  return PartialRedux<Horizontal, BinaryOp, Derived>(derived(), func);
+}
+
+
+/** \returns the result of a full redux operation on the whole matrix or vector using \a func
+  *
+  * The template parameter \a BinaryOp is the type of the functor \a func which must be
+  * an assiociative operator. Both current STL and TR1 functor styles are handled.
+  *
+  * \sa MatrixBase::sum(), MatrixBase::minCoeff(), MatrixBase::maxCoeff(), MatrixBase::verticalRedux(), MatrixBase::horizontalRedux()
+  */
+template<typename Derived>
+template<typename BinaryOp>
+typename ei_result_of<BinaryOp(typename ei_traits<Derived>::Scalar)>::type
+MatrixBase<Derived>::redux(const BinaryOp& func) const
+{
+  if(EIGEN_UNROLLED_LOOPS
+  && SizeAtCompileTime != Dynamic
+  && SizeAtCompileTime <= EIGEN_UNROLLING_LIMIT)
+    return ei_redux_unroller<BinaryOp, Derived, 0,
+       (SizeAtCompileTime>0 && SizeAtCompileTime <= EIGEN_UNROLLING_LIMIT) ?
+        SizeAtCompileTime : Dynamic>::run(derived(), func);
+  else
+  {
+    Scalar res;
+    res = coeff(0,0);
+    for(int i = 1; i < rows(); i++)
+      res = func(res, coeff(i, 0));
+    for(int j = 1; j < cols(); j++)
+      for(int i = 0; i < rows(); i++)
+        res = func(res, coeff(i, j));
+    return res;
+  }
+}
+
+/** \returns the sum of all coefficients of *this
+  *
+  * \sa trace()
+  */
+template<typename Derived>
+typename ei_traits<Derived>::Scalar
+MatrixBase<Derived>::sum() const
+{
+  return this->redux(Eigen::ei_scalar_sum_op());
+}
+
+/** \returns the trace of \c *this, i.e. the sum of the coefficients on the main diagonal.
+  *
+  * \c *this can be any matrix, not necessarily square.
+  *
+  * \sa diagonal(), sum()
+  */
+template<typename Derived>
+typename ei_traits<Derived>::Scalar
+MatrixBase<Derived>::trace() const
+{
+  return diagonal().sum();
+}
+
+/** \returns the minimum of all coefficients of *this
+  */
+template<typename Derived>
+typename ei_traits<Derived>::Scalar
+MatrixBase<Derived>::minCoeff() const
+{
+  return this->redux(Eigen::ei_scalar_min_op());
+}
+
+/** \returns the maximum of all coefficients of *this
+  */
+template<typename Derived>
+typename ei_traits<Derived>::Scalar
+MatrixBase<Derived>::maxCoeff() const
+{
+  return this->redux(Eigen::ei_scalar_max_op());
+}
+
+#endif // EIGEN_REDUX_H
diff --git a/Eigen/src/Core/SumOfCoeffs.h b/Eigen/src/Core/SumOfCoeffs.h
deleted file mode 100644
index 36e75d3e9..000000000
--- a/Eigen/src/Core/SumOfCoeffs.h
+++ /dev/null
@@ -1,102 +0,0 @@
-// 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_SUMOFCOEFFS_H
-#define EIGEN_SUMOFCOEFFS_H
-
-template<int Index, int Size, typename Derived>
-struct ei_sumofcoeffs_unroller
-{
-  static void run(const Derived &v1, typename Derived::Scalar &dot)
-  {
-    ei_sumofcoeffs_unroller<Index-1, Size, Derived>::run(v1, dot);
-    dot += v1.coeff(Index);
-  }
-};
-
-template<int Size, typename Derived>
-struct ei_sumofcoeffs_unroller<0, Size, Derived>
-{
-  static void run(const Derived &v1, typename Derived::Scalar &dot)
-  {
-    dot = v1.coeff(0);
-  }
-};
-
-template<int Index, typename Derived>
-struct ei_sumofcoeffs_unroller<Index, Dynamic, Derived>
-{
-  static void run(const Derived&, typename Derived::Scalar&) {}
-};
-
-// prevent buggy user code from causing an infinite recursion
-template<int Index, typename Derived>
-struct ei_sumofcoeffs_unroller<Index, 0, Derived>
-{
-  static void run(const Derived&, typename Derived::Scalar&)
-{}
-};
-
-/** \returns the sum of all coefficients of *this
-  *
-  * \only_for_vectors
-  *
-  * \sa trace()
-  */
-template<typename Derived>
-typename ei_traits<Derived>::Scalar
-MatrixBase<Derived>::sum() const
-{
-  assert(IsVectorAtCompileTime);
-  Scalar res;
-  if(EIGEN_UNROLLED_LOOPS
-  && SizeAtCompileTime != Dynamic
-  && SizeAtCompileTime <= EIGEN_UNROLLING_LIMIT)
-    ei_sumofcoeffs_unroller<SizeAtCompileTime-1,
-                SizeAtCompileTime <= EIGEN_UNROLLING_LIMIT ? SizeAtCompileTime : Dynamic,
-                Derived>
-      ::run(derived(),res);
-  else
-  {
-    res = coeff(0);
-    for(int i = 1; i < size(); i++)
-      res += coeff(i);
-  }
-  return res;
-}
-
-/** \returns the trace of \c *this, i.e. the sum of the coefficients on the main diagonal.
-  *
-  * \c *this can be any matrix, not necessarily square.
-  *
-  * \sa diagonal(), sum()
-  */
-template<typename Derived>
-typename ei_traits<Derived>::Scalar
-MatrixBase<Derived>::trace() const
-{
-  return diagonal().sum();
-}
-
-#endif // EIGEN_SUMOFCOEFFS_H
diff --git a/Eigen/src/Core/Util.h b/Eigen/src/Core/Util.h
index 71a8294f6..54c56eb3c 100644
--- a/Eigen/src/Core/Util.h
+++ b/Eigen/src/Core/Util.h
@@ -120,6 +120,8 @@ const int RowMajor = 1;
 
 enum CornerType { TopLeft, TopRight, BottomLeft, BottomRight };
 
+enum DirectionType { Vertical, Horizontal };
+
 // just a workaround because GCC seems to not really like empty structs
 #ifdef __GNUG__
   struct ei_empty_struct{char _ei_dummy_;};
diff --git a/Eigen/src/Core/Visitor.h b/Eigen/src/Core/Visitor.h
new file mode 100644
index 000000000..a3a2ef34e
--- /dev/null
+++ b/Eigen/src/Core/Visitor.h
@@ -0,0 +1,182 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008 Gael Guennebaud <g.gael@free.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_VISITOR_H
+#define EIGEN_VISITOR_H
+
+template<typename Visitor, typename Derived, int UnrollCount>
+struct ei_visitor_unroller
+{
+  enum {
+    col = (UnrollCount-1) / Derived::RowsAtCompileTime,
+    row = (UnrollCount-1) % Derived::RowsAtCompileTime
+  };
+
+  static void run(const Derived &mat, Visitor& visitor)
+  {
+    ei_visitor_unroller<Visitor, Derived, UnrollCount-1>::run(mat, visitor);
+    visitor(mat.coeff(row, col), row, col);
+  }
+};
+
+template<typename Visitor, typename Derived>
+struct ei_visitor_unroller<Visitor, Derived, 1>
+{
+  static void run(const Derived &mat, Visitor& visitor)
+  {
+    return visitor.init(mat.coeff(0, 0), 0, 0);
+  }
+};
+
+template<typename Visitor, typename Derived>
+struct ei_visitor_unroller<Visitor, Derived, Dynamic>
+{
+  static void run(const Derived &mat, Visitor& visitor) {}
+};
+
+
+/** Applies the visitor \a visitor to the whole coefficients of the matrix or vector.
+  *
+  * The template parameter \a Visitor is the type of the visitor and provides the following interface:
+  * \code
+  * struct MyVisitor {
+  *   // called for the first coefficient
+  *   void init(const Scalar& value, int i, int j);
+  *   // called for all other coefficients
+  *   void operator() (const Scalar& value, int i, int j);
+  * };
+  * \endcode
+  *
+  * \sa minCoeff(int*,int*), maxCoeff(int*,int*), MatrixBase::redux()
+  */
+template<typename Derived>
+template<typename Visitor>
+void MatrixBase<Derived>::visit(Visitor& visitor) const
+{
+  if(EIGEN_UNROLLED_LOOPS
+  && SizeAtCompileTime != Dynamic
+  && SizeAtCompileTime <= EIGEN_UNROLLING_LIMIT)
+    return ei_visitor_unroller<Visitor, Derived,
+        (SizeAtCompileTime>0 && SizeAtCompileTime <= EIGEN_UNROLLING_LIMIT) ?
+        SizeAtCompileTime : Dynamic>::run(derived(), visitor);
+  else
+  {
+    Scalar res;
+    visitor.init(coeff(0,0), 0, 0);
+    for(int i = 1; i < rows(); i++)
+      visitor(res, coeff(i, 0), i, 0);
+    for(int j = 1; j < cols(); j++)
+      for(int i = 0; i < rows(); i++)
+        visitor(res, coeff(i, j), i, j);
+  }
+}
+
+/** \internal
+  * \brief Base class to implement min and max visitors
+  */
+template <typename Scalar>
+struct ei_coeff_visitor
+{
+  int row, col;
+  Scalar res;
+  void init(const Scalar& value, int i, int j)
+  {
+    res = value;
+    row = i;
+    col = j;
+  }
+};
+
+/** \internal
+  * \brief Visitor computing the min coefficient with its value and coordinates
+  *
+  * \sa ei_coeff_visitor, ei_max_coeff_visitor, MatrixBase::minCoeff(int*, int*)
+  */
+template <typename Scalar>
+struct ei_min_coeff_visitor : ei_coeff_visitor<Scalar>
+{
+  void operator() (const Scalar& value, int i, int j)
+  {
+    if(value < this->res)
+    {
+      this->res = value;
+      this->row = i;
+      this->col = j;
+    }
+  }
+};
+
+/** \internal
+  * \brief Visitor computing the max coefficient with its value and coordinates
+  *
+  * \sa ei_coeff_visitor, ei_min_coeff_visitor, MatrixBase::maxCoeff(int*, int*)
+  */
+template <typename Scalar>
+struct ei_max_coeff_visitor : ei_coeff_visitor<Scalar>
+{
+  void operator() (const Scalar& value, int i, int j)
+  {
+    if(value > this->res)
+    {
+      this->res = value;
+      this->row = i;
+      this->col = j;
+    }
+  }
+};
+
+/** \returns the minimum of all coefficients of *this
+  * and puts in *row and *col its location.
+  *
+  * \sa MatrixBase::maxCoeff(int*,int*), MatrixBase::visitor(), MatrixBase::minCoeff()
+  */
+template<typename Derived>
+typename ei_traits<Derived>::Scalar
+MatrixBase<Derived>::minCoeff(int* row, int* col) const
+{
+  ei_min_coeff_visitor<Scalar> minVisitor;
+  this->visit(minVisitor);
+  *row = minVisitor.row;
+  if (col) *col = minVisitor.col;
+  return minVisitor.res;
+}
+
+/** \returns the maximum of all coefficients of *this
+  * and puts in *row and *col its location.
+  *
+  * \sa MatrixBase::minCoeff(int*,int*), MatrixBase::visitor(), MatrixBase::maxCoeff()
+  */
+template<typename Derived>
+typename ei_traits<Derived>::Scalar
+MatrixBase<Derived>::maxCoeff(int* row, int* col) const
+{
+  ei_max_coeff_visitor<Scalar> maxVisitor;
+  this->visit(maxVisitor);
+  *row = maxVisitor.row;
+  if (col) *col = maxVisitor.col;
+  return maxVisitor.res;
+}
+
+
+#endif // EIGEN_VISITOR_H