From 2b15e001068f548b852d58472b9b29f1a7bf1a2c Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 19 Aug 2013 16:40:50 +0200
Subject: [PATCH] Make ArrayBase operator+=(scalar) and -=(scalar) use
 SelfCwiseBinaryOp optimization

---
 Eigen/Core                         |  2 +-
 Eigen/src/Core/ArrayBase.h         |  6 ++----
 Eigen/src/Core/SelfCwiseBinaryOp.h | 18 ++++++++++++++++++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/Eigen/Core b/Eigen/Core
index 97aa581e2..a508b97f6 100644
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -284,6 +284,7 @@ using std::ptrdiff_t;
   #include "src/Core/Assign.h"
 #endif
 
+#include "src/Core/ArrayBase.h"
 #include "src/Core/util/BlasUtil.h"
 #include "src/Core/DenseStorage.h"
 #include "src/Core/NestByValue.h"
@@ -347,7 +348,6 @@ using std::ptrdiff_t;
 #include "src/Core/Random.h"
 #include "src/Core/Replicate.h"
 #include "src/Core/Reverse.h"
-#include "src/Core/ArrayBase.h"
 #include "src/Core/ArrayWrapper.h"
 
 #ifdef EIGEN_ENABLE_EVALUATORS
diff --git a/Eigen/src/Core/ArrayBase.h b/Eigen/src/Core/ArrayBase.h
index 38852600d..b7c4a1c71 100644
--- a/Eigen/src/Core/ArrayBase.h
+++ b/Eigen/src/Core/ArrayBase.h
@@ -123,10 +123,8 @@ template<typename Derived> class ArrayBase
       return internal::assign_selector<Derived,Derived>::run(derived(), other.derived());
     }
 
-    Derived& operator+=(const Scalar& scalar)
-    { return *this = derived() + scalar; }
-    Derived& operator-=(const Scalar& scalar)
-    { return *this = derived() - scalar; }
+    Derived& operator+=(const Scalar& scalar);
+    Derived& operator-=(const Scalar& scalar);
 
     template<typename OtherDerived>
     Derived& operator+=(const ArrayBase<OtherDerived>& other);
diff --git a/Eigen/src/Core/SelfCwiseBinaryOp.h b/Eigen/src/Core/SelfCwiseBinaryOp.h
index 96012eaf8..3d2deff98 100644
--- a/Eigen/src/Core/SelfCwiseBinaryOp.h
+++ b/Eigen/src/Core/SelfCwiseBinaryOp.h
@@ -177,6 +177,24 @@ inline Derived& DenseBase<Derived>::operator*=(const Scalar& other)
   return derived();
 }
 
+template<typename Derived>
+inline Derived& ArrayBase<Derived>::operator+=(const Scalar& other)
+{
+  typedef typename Derived::PlainObject PlainObject;
+  SelfCwiseBinaryOp<internal::scalar_sum_op<Scalar>, Derived, typename PlainObject::ConstantReturnType> tmp(derived());
+  tmp = PlainObject::Constant(rows(),cols(),other);
+  return derived();
+}
+
+template<typename Derived>
+inline Derived& ArrayBase<Derived>::operator-=(const Scalar& other)
+{
+  typedef typename Derived::PlainObject PlainObject;
+  SelfCwiseBinaryOp<internal::scalar_difference_op<Scalar>, Derived, typename PlainObject::ConstantReturnType> tmp(derived());
+  tmp = PlainObject::Constant(rows(),cols(),other);
+  return derived();
+}
+
 template<typename Derived>
 inline Derived& DenseBase<Derived>::operator/=(const Scalar& other)
 {