From 3cb6e21f80150345d8d8eeaf75b185e66a4a3c95 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 9 Apr 2013 11:12:35 +0200
Subject: [PATCH] Fix bug #562: add vector-wise normalized and normalize
 functions

---
 Eigen/src/Core/VectorwiseOp.h | 39 +++++++++++++++++++++++++++++++++++
 test/vectorwiseop.cpp         | 24 +++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/Eigen/src/Core/VectorwiseOp.h b/Eigen/src/Core/VectorwiseOp.h
index f48ec884c..4549641dd 100644
--- a/Eigen/src/Core/VectorwiseOp.h
+++ b/Eigen/src/Core/VectorwiseOp.h
@@ -233,6 +233,28 @@ template<typename ExpressionType, int Direction> class VectorwiseOp
                        Direction==Vertical   ? 1 : m_matrix.rows(),
                        Direction==Horizontal ? 1 : m_matrix.cols());
     }
+    
+    template<typename OtherDerived> struct OppositeExtendedType {
+      typedef Replicate<OtherDerived,
+                        Direction==Horizontal ? 1 : ExpressionType::RowsAtCompileTime,
+                        Direction==Vertical   ? 1 : ExpressionType::ColsAtCompileTime> Type;
+    };
+
+    /** \internal
+      * Replicates a vector in the opposite direction to match the size of \c *this */
+    template<typename OtherDerived>
+    typename OppositeExtendedType<OtherDerived>::Type
+    extendedToOpposite(const DenseBase<OtherDerived>& other) const
+    {
+      EIGEN_STATIC_ASSERT(EIGEN_IMPLIES(Direction==Horizontal, OtherDerived::MaxColsAtCompileTime==1),
+                          YOU_PASSED_A_ROW_VECTOR_BUT_A_COLUMN_VECTOR_WAS_EXPECTED)
+      EIGEN_STATIC_ASSERT(EIGEN_IMPLIES(Direction==Vertical, OtherDerived::MaxRowsAtCompileTime==1),
+                          YOU_PASSED_A_COLUMN_VECTOR_BUT_A_ROW_VECTOR_WAS_EXPECTED)
+      return typename OppositeExtendedType<OtherDerived>::Type
+                      (other.derived(),
+                       Direction==Horizontal  ? 1 : m_matrix.rows(),
+                       Direction==Vertical    ? 1 : m_matrix.cols());
+    }
 
   public:
 
@@ -504,6 +526,23 @@ template<typename ExpressionType, int Direction> class VectorwiseOp
       EIGEN_STATIC_ASSERT_SAME_XPR_KIND(ExpressionType, OtherDerived)
       return m_matrix / extendedTo(other.derived());
     }
+    
+    /** \returns an expression where each column of row of the referenced matrix are normalized.
+      * The referenced matrix is \b not modified.
+      * \sa MatrixBase::normalized(), normalize()
+      */
+    CwiseBinaryOp<internal::scalar_quotient_op<Scalar>,
+                  const ExpressionTypeNestedCleaned,
+                  const typename OppositeExtendedType<typename ReturnType<internal::member_norm,RealScalar>::Type>::Type>
+    normalized() const { return m_matrix.cwiseQuotient(extendedToOpposite(this->norm())); }
+    
+    
+    /** Normalize in-place each row or columns of the referenced matrix.
+      * \sa MatrixBase::normalize(), normalized()
+      */
+    void normalize() {
+      m_matrix = this->normalized();
+    }
 
 /////////// Geometry module ///////////
 
diff --git a/test/vectorwiseop.cpp b/test/vectorwiseop.cpp
index b938e3957..904b51664 100644
--- a/test/vectorwiseop.cpp
+++ b/test/vectorwiseop.cpp
@@ -111,6 +111,8 @@ template<typename MatrixType> void vectorwiseop_matrix(const MatrixType& m)
   typedef typename NumTraits<Scalar>::Real RealScalar;
   typedef Matrix<Scalar, MatrixType::RowsAtCompileTime, 1> ColVectorType;
   typedef Matrix<Scalar, 1, MatrixType::ColsAtCompileTime> RowVectorType;
+  typedef Matrix<RealScalar, MatrixType::RowsAtCompileTime, 1> RealColVectorType;
+  typedef Matrix<RealScalar, 1, MatrixType::ColsAtCompileTime> RealRowVectorType;
 
   Index rows = m.rows();
   Index cols = m.cols();
@@ -123,6 +125,8 @@ template<typename MatrixType> void vectorwiseop_matrix(const MatrixType& m)
 
   ColVectorType colvec = ColVectorType::Random(rows);
   RowVectorType rowvec = RowVectorType::Random(cols);
+  RealColVectorType rcres;
+  RealRowVectorType rrres;
 
   // test addition
 
@@ -159,6 +163,26 @@ template<typename MatrixType> void vectorwiseop_matrix(const MatrixType& m)
 
   VERIFY_RAISES_ASSERT(m2.rowwise() -= rowvec.transpose());
   VERIFY_RAISES_ASSERT(m1.rowwise() - rowvec.transpose());
+  
+  // test norm
+  rrres = m1.colwise().norm();
+  VERIFY_IS_APPROX(rrres(c), m1.col(c).norm());
+  rcres = m1.rowwise().norm();
+  VERIFY_IS_APPROX(rcres(r), m1.row(r).norm());
+  
+  // test normalized
+  m2 = m1.colwise().normalized();
+  VERIFY_IS_APPROX(m2.col(c), m1.col(c).normalized());
+  m2 = m1.rowwise().normalized();
+  VERIFY_IS_APPROX(m2.row(r), m1.row(r).normalized());
+  
+  // test normalize
+  m2 = m1;
+  m2.colwise().normalize();
+  VERIFY_IS_APPROX(m2.col(c), m1.col(c).normalized());
+  m2 = m1;
+  m2.rowwise().normalize();
+  VERIFY_IS_APPROX(m2.row(r), m1.row(r).normalized());
 }
 
 void test_vectorwiseop()