added mean() reduction

3 files changed, 23 insertions, 3 deletions

diff --git a/Eigen/src/Array/VectorwiseOp.h b/Eigen/src/Array/VectorwiseOp.h
index 4cb0083fa..6f6c2c8a7 100644
--- a/Eigen/src/Array/VectorwiseOp.h
+++ b/Eigen/src/Array/VectorwiseOp.h
@@ -122,6 +122,7 @@ class PartialReduxExpr : ei_no_assignment_operator,
 EIGEN_MEMBER_FUNCTOR(squaredNorm, Size * NumTraits<Scalar>::MulCost + (Size-1)*NumTraits<Scalar>::AddCost);
 EIGEN_MEMBER_FUNCTOR(norm, (Size+5) * NumTraits<Scalar>::MulCost + (Size-1)*NumTraits<Scalar>::AddCost);
 EIGEN_MEMBER_FUNCTOR(sum, (Size-1)*NumTraits<Scalar>::AddCost);
+EIGEN_MEMBER_FUNCTOR(mean, (Size-1)*NumTraits<Scalar>::AddCost);
 EIGEN_MEMBER_FUNCTOR(minCoeff, (Size-1)*NumTraits<Scalar>::AddCost);
 EIGEN_MEMBER_FUNCTOR(maxCoeff, (Size-1)*NumTraits<Scalar>::AddCost);
 EIGEN_MEMBER_FUNCTOR(all, (Size-1)*NumTraits<Scalar>::AddCost);
@@ -297,6 +298,13 @@ template<typename ExpressionType, int Direction> class VectorwiseOp
     const typename ReturnType<ei_member_sum>::Type sum() const
     { return _expression(); }
 
+    /** \returns a row (or column) vector expression of the mean
+    * of each column (or row) of the referenced expression.
+    *
+    * \sa MatrixBase::mean() */
+    const typename ReturnType<ei_member_mean>::Type mean() const
+    { return _expression(); }
+
     /** \returns a row (or column) vector expression representing
       * whether \b all coefficients of each respective column (or row) are \c true.
       *
diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index 2691fdecd..cb1589f85 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -645,8 +645,9 @@ template<typename Derived> class MatrixBase
     const CwiseBinaryOp<CustomBinaryOp, Derived, OtherDerived>
     binaryExpr(const MatrixBase<OtherDerived> &other, const CustomBinaryOp& func = CustomBinaryOp()) const;
 
-
+    
     Scalar sum() const;
+    Scalar mean() const;
     Scalar trace() const;
 
     Scalar prod() const;
diff --git a/Eigen/src/Core/Redux.h b/Eigen/src/Core/Redux.h
index 0df095750..9f796157a 100644
--- a/Eigen/src/Core/Redux.h
+++ b/Eigen/src/Core/Redux.h
@@ -342,7 +342,7 @@ MatrixBase<Derived>::maxCoeff() const
 
 /** \returns the sum of all coefficients of *this
   *
-  * \sa trace(), prod()
+  * \sa trace(), prod(), mean()
   */
 template<typename Derived>
 EIGEN_STRONG_INLINE typename ei_traits<Derived>::Scalar
@@ -351,12 +351,23 @@ MatrixBase<Derived>::sum() const
   return this->redux(Eigen::ei_scalar_sum_op<Scalar>());
 }
 
+/** \returns the mean of all coefficients of *this
+*
+* \sa trace(), prod(), sum()
+*/
+template<typename Derived>
+EIGEN_STRONG_INLINE typename ei_traits<Derived>::Scalar
+MatrixBase<Derived>::mean() const
+{
+  return this->redux(Eigen::ei_scalar_sum_op<Scalar>()) / this->size();
+}
+
 /** \returns the product of all coefficients of *this
   *
   * Example: \include MatrixBase_prod.cpp
   * Output: \verbinclude MatrixBase_prod.out
   *
-  * \sa sum()
+  * \sa sum(), mean(), trace()
   */
 template<typename Derived>
 EIGEN_STRONG_INLINE typename ei_traits<Derived>::Scalar