From a669052f12d6d71ba815764d6419726d64fef675 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Mon, 9 Jun 2014 09:45:30 -0700
Subject: [PATCH] Improved support for rvalues in tensor expressions.

---
 .../Eigen/CXX11/src/Tensor/TensorBase.h       | 58 ++++++++++++++-----
 .../CXX11/src/Tensor/TensorContraction.h      |  4 ++
 .../CXX11/src/Tensor/TensorConvolution.h      |  4 ++
 .../Eigen/CXX11/src/Tensor/TensorExpr.h       |  8 +++
 .../src/Tensor/TensorForwardDeclarations.h    |  6 +-
 .../Eigen/CXX11/src/Tensor/TensorMorphing.h   |  5 +-
 .../Eigen/CXX11/src/Tensor/TensorTraits.h     |  6 +-
 7 files changed, 71 insertions(+), 20 deletions(-)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h b/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
index 932e5c82d..e447a5d40 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorBase.h
@@ -22,7 +22,7 @@ namespace Eigen {
   */
 
 template<typename Derived>
-class TensorBase
+class TensorBase<Derived, ReadOnlyAccessors>
 {
   public:
     typedef typename internal::traits<Derived>::Scalar Scalar;
@@ -30,19 +30,6 @@ class TensorBase
     typedef Scalar CoeffReturnType;
     typedef typename internal::packet_traits<Scalar>::type PacketReturnType;
 
-    EIGEN_DEVICE_FUNC
-    EIGEN_STRONG_INLINE Derived& setZero() {
-      return setConstant(Scalar(0));
-    }
-    EIGEN_DEVICE_FUNC
-    EIGEN_STRONG_INLINE Derived& setConstant(const Scalar& val) {
-      return derived() = constant(val);
-    }
-    EIGEN_DEVICE_FUNC
-    EIGEN_STRONG_INLINE Derived& setRandom() {
-      return derived() = random();
-    }
-
     // Nullary operators
     EIGEN_DEVICE_FUNC
     EIGEN_STRONG_INLINE const TensorCwiseNullaryOp<internal::scalar_constant_op<Scalar>, const Derived>
@@ -224,14 +211,53 @@ class TensorBase
       return TensorReshapingOp<const Derived, const NewDimensions>(derived(), newDimensions);
     }
 
+  protected:
+    template <typename OtherDerived, int AccessLevel> friend class TensorBase;
+    EIGEN_DEVICE_FUNC
+    EIGEN_STRONG_INLINE const Derived& derived() const { return *static_cast<const Derived*>(this); }
+};
+
+
+template<typename Derived>
+class TensorBase<Derived, WriteAccessors> : public TensorBase<Derived, ReadOnlyAccessors> {
+ public:
+    typedef typename internal::traits<Derived>::Scalar Scalar;
+    typedef typename internal::traits<Derived>::Index Index;
+    typedef Scalar CoeffReturnType;
+    typedef typename internal::packet_traits<Scalar>::type PacketReturnType;
+
+    template <typename OtherDerived, int AccessLevel> friend class TensorBase;
+
+    EIGEN_DEVICE_FUNC
+    EIGEN_STRONG_INLINE Derived& setZero() {
+      return setConstant(Scalar(0));
+    }
+    EIGEN_DEVICE_FUNC
+    EIGEN_STRONG_INLINE Derived& setConstant(const Scalar& val) {
+      return derived() = this->constant(val);
+    }
+    EIGEN_DEVICE_FUNC
+    EIGEN_STRONG_INLINE Derived& setRandom() {
+      return derived() = this->random();
+    }
+
+    template<typename OtherDerived> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+    Derived& operator+=(const OtherDerived& other) {
+      return derived() = TensorCwiseBinaryOp<internal::scalar_sum_op<Scalar>, const Derived, const OtherDerived>(derived(), other.derived());
+    }
+
+    template<typename OtherDerived> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+    Derived& operator-=(const OtherDerived& other) {
+      return derived() = TensorCwiseBinaryOp<internal::scalar_difference_op<Scalar>, const Derived, const OtherDerived>(derived(), other.derived());
+    }
+
     // Select the device on which to evaluate the expression.
     template <typename DeviceType>
     TensorDevice<Derived, DeviceType> device(const DeviceType& device) {
       return TensorDevice<Derived, DeviceType>(device, derived());
     }
 
-  protected:
-    template <typename OtherDerived> friend class TensorBase;
+ protected:
     EIGEN_DEVICE_FUNC
     EIGEN_STRONG_INLINE Derived& derived() { return *static_cast<Derived*>(this); }
     EIGEN_DEVICE_FUNC
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h b/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h
index d424df36e..d371eb76d 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h
@@ -35,6 +35,10 @@ struct traits<TensorContractionOp<Dimensions, LhsXprType, RhsXprType> >
   typedef typename RhsXprType::Nested RhsNested;
   typedef typename remove_reference<LhsNested>::type _LhsNested;
   typedef typename remove_reference<RhsNested>::type _RhsNested;
+
+  enum {
+    Flags = 0,
+  };
 };
 
 template<typename Dimensions, typename LhsXprType, typename RhsXprType>
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorConvolution.h b/unsupported/Eigen/CXX11/src/Tensor/TensorConvolution.h
index ca2e0e562..501e9a522 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorConvolution.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorConvolution.h
@@ -35,6 +35,10 @@ struct traits<TensorConvolutionOp<Dimensions, InputXprType, KernelXprType> >
   typedef typename KernelXprType::Nested RhsNested;
   typedef typename remove_reference<LhsNested>::type _LhsNested;
   typedef typename remove_reference<RhsNested>::type _RhsNested;
+
+  enum {
+    Flags = 0,
+  };
 };
 
 template<typename Dimensions, typename InputXprType, typename KernelXprType>
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorExpr.h b/unsupported/Eigen/CXX11/src/Tensor/TensorExpr.h
index 60908ee94..de66da13f 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorExpr.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorExpr.h
@@ -36,6 +36,10 @@ struct traits<TensorCwiseNullaryOp<NullaryOp, XprType> >
   typedef typename XprType::Scalar Scalar;
   typedef typename XprType::Nested XprTypeNested;
   typedef typename remove_reference<XprTypeNested>::type _XprTypeNested;
+
+  enum {
+    Flags = 0,
+  };
 };
 
 }  // end namespace internal
@@ -153,6 +157,10 @@ struct traits<TensorCwiseBinaryOp<BinaryOp, LhsXprType, RhsXprType> >
   typedef typename RhsXprType::Nested RhsNested;
   typedef typename remove_reference<LhsNested>::type _LhsNested;
   typedef typename remove_reference<RhsNested>::type _RhsNested;
+
+  enum {
+    Flags = 0,
+  };
 };
 
 template<typename BinaryOp, typename LhsXprType, typename RhsXprType>
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorForwardDeclarations.h b/unsupported/Eigen/CXX11/src/Tensor/TensorForwardDeclarations.h
index b8833362c..1fb90478f 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorForwardDeclarations.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorForwardDeclarations.h
@@ -15,7 +15,7 @@ namespace Eigen {
 template<typename Scalar_, std::size_t NumIndices_, int Options_ = 0> class Tensor;
 template<typename Scalar_, typename Dimensions, int Options_ = 0> class TensorFixedSize;
 template<typename PlainObjectType, int Options_ = Unaligned> class TensorMap;
-template<typename Derived> class TensorBase;
+template<typename Derived, int AccessLevel = internal::accessors_level<Derived>::value> class TensorBase;
 
 template<typename NullaryOp, typename PlainObjectType> class TensorCwiseNullaryOp;
 template<typename UnaryOp, typename XprType> class TensorCwiseUnaryOp;
@@ -29,6 +29,10 @@ template<typename ExpressionType, typename DeviceType> class TensorDevice;
 // Move to internal?
 template<typename Derived> struct TensorEvaluator;
 
+namespace internal {
+template<typename Derived, typename OtherDerived, bool Vectorizable> struct TensorAssign;
+}  // end namespace internal
+
 }  // end namespace Eigen
 
 #endif // EIGEN_CXX11_TENSOR_TENSOR_FORWARD_DECLARATIONS_H
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h b/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h
index 3e089fe1e..7d5f9271e 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h
@@ -21,7 +21,7 @@ namespace Eigen {
   */
 namespace internal {
 template<typename XprType, typename NewDimensions>
-struct traits<TensorReshapingOp<XprType, NewDimensions> >
+struct traits<TensorReshapingOp<XprType, NewDimensions> > : public traits<XprType>
 {
   // Type promotion to handle the case where the types of the lhs and the rhs are different.
   typedef typename XprType::Scalar Scalar;
@@ -81,6 +81,7 @@ template<typename ArgType, typename NewDimensions>
 struct TensorEvaluator<const TensorReshapingOp<ArgType, NewDimensions> >
 {
   typedef TensorReshapingOp<ArgType, NewDimensions> XprType;
+  typedef NewDimensions Dimensions;
 
   enum {
     IsAligned = TensorEvaluator<ArgType>::IsAligned,
@@ -95,7 +96,7 @@ struct TensorEvaluator<const TensorReshapingOp<ArgType, NewDimensions> >
   typedef typename XprType::CoeffReturnType CoeffReturnType;
   typedef typename XprType::PacketReturnType PacketReturnType;
 
-  const NewDimensions& dimensions() const { return m_dimensions; }
+  const Dimensions& dimensions() const { return m_dimensions; }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CoeffReturnType coeff(Index index) const
   {
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h b/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h
index 2de698a57..40f805741 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h
@@ -52,7 +52,7 @@ struct traits<Tensor<Scalar_, NumIndices_, Options_> >
   typedef DenseIndex Index;
   enum {
     Options = Options_,
-    Flags = compute_tensor_flags<Scalar_, Options_>::ret,
+    Flags = compute_tensor_flags<Scalar_, Options_>::ret | LvalueBit,
   };
 };
 
@@ -63,6 +63,10 @@ struct traits<TensorFixedSize<Scalar_, Dimensions, Options_> >
   typedef Scalar_ Scalar;
   typedef Dense StorageKind;
   typedef DenseIndex Index;
+  enum {
+    Options = Options_,
+    Flags = compute_tensor_flags<Scalar_, Options_>::ret | LvalueBit,
+  };
 };