From bbb8854bf775a9691cacf6f0fb6e8bed141100c7 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Wed, 13 Apr 2016 13:02:34 +0200
Subject: [PATCH] Enable half-packet in reduxions.

---
 Eigen/src/Core/Redux.h | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/Eigen/src/Core/Redux.h b/Eigen/src/Core/Redux.h
index d170cae29..98b2fd868 100644
--- a/Eigen/src/Core/Redux.h
+++ b/Eigen/src/Core/Redux.h
@@ -27,8 +27,9 @@ template<typename Func, typename Derived>
 struct redux_traits
 {
 public:
+    typedef typename find_best_packet<typename Derived::Scalar,Derived::SizeAtCompileTime>::type PacketType;
   enum {
-    PacketSize = packet_traits<typename Derived::Scalar>::size,
+    PacketSize = unpacket_traits<PacketType>::size,
     InnerMaxSize = int(Derived::IsRowMajor)
                  ? Derived::MaxColsAtCompileTime
                  : Derived::MaxRowsAtCompileTime
@@ -137,12 +138,12 @@ template<typename Func, typename Derived, int Start, int Length>
 struct redux_vec_unroller
 {
   enum {
-    PacketSize = packet_traits<typename Derived::Scalar>::size,
+    PacketSize = redux_traits<Func, Derived>::PacketSize,
     HalfLength = Length/2
   };
 
   typedef typename Derived::Scalar Scalar;
-  typedef typename packet_traits<Scalar>::type PacketScalar;
+  typedef typename redux_traits<Func, Derived>::PacketType PacketScalar;
 
   static EIGEN_STRONG_INLINE PacketScalar run(const Derived &mat, const Func& func)
   {
@@ -156,14 +157,14 @@ template<typename Func, typename Derived, int Start>
 struct redux_vec_unroller<Func, Derived, Start, 1>
 {
   enum {
-    index = Start * packet_traits<typename Derived::Scalar>::size,
+    index = Start * redux_traits<Func, Derived>::PacketSize,
     outer = index / int(Derived::InnerSizeAtCompileTime),
     inner = index % int(Derived::InnerSizeAtCompileTime),
     alignment = Derived::Alignment
   };
 
   typedef typename Derived::Scalar Scalar;
-  typedef typename packet_traits<Scalar>::type PacketScalar;
+  typedef typename redux_traits<Func, Derived>::PacketType PacketScalar;
 
   static EIGEN_STRONG_INLINE PacketScalar run(const Derived &mat, const Func&)
   {
@@ -209,13 +210,13 @@ template<typename Func, typename Derived>
 struct redux_impl<Func, Derived, LinearVectorizedTraversal, NoUnrolling>
 {
   typedef typename Derived::Scalar Scalar;
-  typedef typename packet_traits<Scalar>::type PacketScalar;
+  typedef typename redux_traits<Func, Derived>::PacketType PacketScalar;
 
   static Scalar run(const Derived &mat, const Func& func)
   {
     const Index size = mat.size();
     
-    const Index packetSize = packet_traits<Scalar>::size;
+    const Index packetSize = redux_traits<Func, Derived>::PacketSize;
     const int packetAlignment = unpacket_traits<PacketScalar>::alignment;
     enum {
       alignment0 = (bool(Derived::Flags & DirectAccessBit) && bool(packet_traits<Scalar>::AlignedOnScalar)) ? int(packetAlignment) : int(Unaligned),
@@ -268,7 +269,7 @@ template<typename Func, typename Derived, int Unrolling>
 struct redux_impl<Func, Derived, SliceVectorizedTraversal, Unrolling>
 {
   typedef typename Derived::Scalar Scalar;
-  typedef typename packet_traits<Scalar>::type PacketType;
+  typedef typename redux_traits<Func, Derived>::PacketType PacketType;
 
   EIGEN_DEVICE_FUNC static Scalar run(const Derived &mat, const Func& func)
   {
@@ -276,7 +277,7 @@ struct redux_impl<Func, Derived, SliceVectorizedTraversal, Unrolling>
     const Index innerSize = mat.innerSize();
     const Index outerSize = mat.outerSize();
     enum {
-      packetSize = packet_traits<Scalar>::size
+      packetSize = redux_traits<Func, Derived>::PacketSize
     };
     const Index packetedInnerSize = ((innerSize)/packetSize)*packetSize;
     Scalar res;
@@ -306,9 +307,10 @@ template<typename Func, typename Derived>
 struct redux_impl<Func, Derived, LinearVectorizedTraversal, CompleteUnrolling>
 {
   typedef typename Derived::Scalar Scalar;
-  typedef typename packet_traits<Scalar>::type PacketScalar;
+
+  typedef typename redux_traits<Func, Derived>::PacketType PacketScalar;
   enum {
-    PacketSize = packet_traits<Scalar>::size,
+    PacketSize = redux_traits<Func, Derived>::PacketSize,
     Size = Derived::SizeAtCompileTime,
     VectorizedSize = (Size / PacketSize) * PacketSize
   };
@@ -367,11 +369,11 @@ public:
   { return m_evaluator.coeff(index); }
 
   template<int LoadMode, typename PacketType>
-  PacketReturnType packet(Index row, Index col) const
+  PacketType packet(Index row, Index col) const
   { return m_evaluator.template packet<LoadMode,PacketType>(row, col); }
 
   template<int LoadMode, typename PacketType>
-  PacketReturnType packet(Index index) const
+  PacketType packet(Index index) const
   { return m_evaluator.template packet<LoadMode,PacketType>(index); }
   
   EIGEN_DEVICE_FUNC
@@ -379,7 +381,7 @@ public:
   { return m_evaluator.coeff(IsRowMajor ? outer : inner, IsRowMajor ? inner : outer); }
   
   template<int LoadMode, typename PacketType>
-  PacketReturnType packetByOuterInner(Index outer, Index inner) const
+  PacketType packetByOuterInner(Index outer, Index inner) const
   { return m_evaluator.template packet<LoadMode,PacketType>(IsRowMajor ? outer : inner, IsRowMajor ? inner : outer); }
   
   const XprType & nestedExpression() const { return m_xpr; }