Added support for vectorized type casting of tensors

unsupported/Eigen/CXX11/Tensor

@@ -65,6 +65,7 @@
 #include "unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h"
 #include "unsupported/Eigen/CXX11/src/Tensor/TensorContractionThreadPool.h"
 #include "unsupported/Eigen/CXX11/src/Tensor/TensorContractionCuda.h"
+#include "unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h"
 #include "unsupported/Eigen/CXX11/src/Tensor/TensorConvolution.h"
 #include "unsupported/Eigen/CXX11/src/Tensor/TensorPatch.h"
 #include "unsupported/Eigen/CXX11/src/Tensor/TensorImagePatch.h"

unsupported/Eigen/CXX11/src/Tensor/TensorBase.h

@@ -164,9 +164,9 @@ class TensorBase<Derived, ReadOnlyAccessors>
     }
 
     template <typename NewType> EIGEN_DEVICE_FUNC
-    EIGEN_STRONG_INLINE const TensorCwiseUnaryOp<internal::scalar_cast_op<Scalar, NewType>, const Derived>
+    EIGEN_STRONG_INLINE const TensorConversionOp<NewType, const Derived>
     cast() const {
-      return unaryExpr(internal::scalar_cast_op<Scalar, NewType>());
+      return TensorConversionOp<NewType, const Derived>(derived());
     }
 
     // Generic binary operation support.

unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h

@@ -0,0 +1,202 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2015 Benoit Steiner <benoit.steiner.goog@gmail.com>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef EIGEN_CXX11_TENSOR_TENSOR_CONVERSION_H
+#define EIGEN_CXX11_TENSOR_TENSOR_CONVERSION_H
+
+namespace Eigen {
+
+/** \class TensorConversionOp
+  * \ingroup CXX11_Tensor_Module
+  *
+  * \brief Tensor conversion class. This class makes it possible to vectorize
+  * type casting operations when the number of scalars per packet in the source
+  * and the destination type differ
+  */
+namespace internal {
+template<typename TargetType, typename XprType>
+struct traits<TensorConversionOp<TargetType, XprType> >
+{
+  // Type promotion to handle the case where the types of the lhs and the rhs are different.
+  typedef TargetType Scalar;
+  typedef typename packet_traits<Scalar>::type Packet;
+  typedef typename traits<XprType>::StorageKind StorageKind;
+  typedef typename traits<XprType>::Index Index;
+  typedef typename XprType::Nested Nested;
+  typedef typename remove_reference<Nested>::type _Nested;
+  static const int NumDimensions = traits<XprType>::NumDimensions;
+  static const int Layout = traits<XprType>::Layout;
+  enum { Flags = 0 };
+};
+
+template<typename TargetType, typename XprType>
+struct eval<TensorConversionOp<TargetType, XprType>, Eigen::Dense>
+{
+  typedef const TensorConversionOp<TargetType, XprType>& type;
+};
+
+template<typename TargetType, typename XprType>
+struct nested<TensorConversionOp<TargetType, XprType>, 1, typename eval<TensorConversionOp<TargetType, XprType> >::type>
+{
+  typedef TensorConversionOp<TargetType, XprType> type;
+};
+
+}  // end namespace internal
+
+
+template <typename TensorEvaluator, typename SrcPacket, typename TgtPacket, int SrcCoeffRatio, int TgtCoeffRatio>
+struct PacketConverter {
+  PacketConverter(const TensorEvaluator& impl)
+      : m_impl(impl) {}
+
+  template<int LoadMode, typename Index>
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TgtPacket packet(Index index) const {
+    return internal::pcast<SrcPacket, TgtPacket>(m_impl.template packet<LoadMode>(index));
+  }
+
+ private:
+  const TensorEvaluator& m_impl;
+};
+
+
+template <typename TensorEvaluator, typename SrcPacket, typename TgtPacket>
+struct PacketConverter<TensorEvaluator, SrcPacket, TgtPacket, 2, 1> {
+  PacketConverter(const TensorEvaluator& impl)
+      : m_impl(impl) {}
+
+  template<int LoadMode, typename Index>
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TgtPacket packet(Index index) const {
+    const int SrcPacketSize = internal::unpacket_traits<SrcPacket>::size;
+
+    SrcPacket src1 = m_impl.template packet<LoadMode>(index);
+    SrcPacket src2 = m_impl.template packet<LoadMode>(index + SrcPacketSize);
+    TgtPacket result = internal::pcast<SrcPacket, TgtPacket>(src1, src2);
+    return result;
+  }
+
+ private:
+  const TensorEvaluator& m_impl;
+};
+
+
+template <typename TensorEvaluator, typename SrcPacket, typename TgtPacket>
+struct PacketConverter<TensorEvaluator, SrcPacket, TgtPacket, 1, 2> {
+  PacketConverter(const TensorEvaluator& impl)
+      : m_impl(impl), m_maxIndex(impl.dimensions().TotalSize()) {}
+
+  template<int LoadMode, typename Index>
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TgtPacket packet(Index index) const {
+    const int SrcPacketSize = internal::unpacket_traits<SrcPacket>::size;
+    if (index + SrcPacketSize < m_maxIndex) {
+      return internal::pcast<SrcPacket, TgtPacket>(m_impl.template packet<LoadMode>(index));
+    } else {
+      const int TgtPacketSize = internal::unpacket_traits<TgtPacket>::size;
+      EIGEN_ALIGN_DEFAULT typename internal::unpacket_traits<TgtPacket>::type values[TgtPacketSize];
+      for (int i = 0; i < TgtPacketSize; ++i) {
+        values[i] = m_impl.coeff(index+i);
+      }
+      TgtPacket rslt = internal::pload<TgtPacket>(values);
+      return rslt;
+    }
+  }
+
+ private:
+  const TensorEvaluator& m_impl;
+  const typename TensorEvaluator::Index m_maxIndex;
+};
+
+template<typename TargetType, typename XprType>
+class TensorConversionOp : public TensorBase<TensorConversionOp<TargetType, XprType>, ReadOnlyAccessors>
+{
+  public:
+    typedef typename internal::traits<TensorConversionOp>::Scalar Scalar;
+    typedef typename internal::traits<TensorConversionOp>::Packet Packet;
+    typedef typename internal::traits<TensorConversionOp>::StorageKind StorageKind;
+    typedef typename internal::traits<TensorConversionOp>::Index Index;
+    typedef typename internal::nested<TensorConversionOp>::type Nested;
+    typedef typename XprType::CoeffReturnType CoeffReturnType;
+    typedef typename XprType::PacketReturnType PacketReturnType;
+    typedef typename NumTraits<Scalar>::Real RealScalar;
+
+    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorConversionOp(const XprType& xpr)
+        : m_xpr(xpr) {}
+
+    EIGEN_DEVICE_FUNC
+    const typename internal::remove_all<typename XprType::Nested>::type&
+    expression() const { return m_xpr; }
+
+  protected:
+    typename XprType::Nested m_xpr;
+};
+
+
+
+
+// Eval as rvalue
+template<typename TargetType, typename ArgType, typename Device>
+struct TensorEvaluator<const TensorConversionOp<TargetType, ArgType>, Device>
+{
+  typedef TensorConversionOp<TargetType, ArgType> XprType;
+  typedef typename XprType::Index Index;
+  typedef typename TensorEvaluator<ArgType, Device>::Dimensions Dimensions;
+  typedef TargetType Scalar;
+  typedef TargetType CoeffReturnType;
+  typedef typename internal::remove_all<typename internal::traits<ArgType>::Scalar>::type SrcType;
+  typedef typename internal::traits<XprType>::Packet PacketReturnType;
+  typedef typename internal::packet_traits<SrcType>::type PacketSourceType;
+
+  enum {
+    IsAligned = false,
+    PacketAccess = TensorEvaluator<ArgType, Device>::PacketAccess && internal::type_casting_traits<SrcType, TargetType>::VectorizedCast,
+    Layout = TensorEvaluator<ArgType, Device>::Layout,
+  };
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorEvaluator(const XprType& op, const Device& device)
+    : m_impl(op.expression(), device)
+  {
+  }
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Dimensions& dimensions() const { return m_impl.dimensions(); }
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool evalSubExprsIfNeeded(Scalar* /*data*/)
+  {
+    m_impl.evalSubExprsIfNeeded(NULL);
+    return true;
+  }
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void cleanup()
+  {
+    m_impl.cleanup();
+  }
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CoeffReturnType coeff(Index index) const
+  {
+    internal::scalar_cast_op<SrcType, TargetType> converter;
+    return converter(m_impl.coeff(index));
+  }
+
+  template<int LoadMode>
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE PacketReturnType packet(Index index) const
+  {
+    const int SrcCoeffRatio = internal::type_casting_traits<SrcType, TargetType>::SrcCoeffRatio;
+    const int TgtCoeffRatio = internal::type_casting_traits<SrcType, TargetType>::TgtCoeffRatio;
+    PacketConverter<TensorEvaluator<ArgType, Device>, PacketSourceType, PacketReturnType,
+                    SrcCoeffRatio, TgtCoeffRatio> converter(m_impl);
+    return converter.template packet<LoadMode>(index);
+  }
+
+  EIGEN_DEVICE_FUNC Scalar* data() const { return NULL; }
+
+  protected:
+    TensorEvaluator<ArgType, Device> m_impl;
+};
+
+} // end namespace Eigen
+
+#endif // EIGEN_CXX11_TENSOR_TENSOR_CONVERSION_H

unsupported/Eigen/CXX11/src/Tensor/TensorForwardDeclarations.h

@@ -25,6 +25,7 @@ template<typename IfXprType, typename ThenXprType, typename ElseXprType> class T
 template<typename Op, typename Dims, typename XprType> class TensorReductionOp;
 template<typename Axis, typename LeftXprType, typename RightXprType> class TensorConcatenationOp;
 template<typename Dimensions, typename LeftXprType, typename RightXprType> class TensorContractionOp;
+template<typename TargetType, typename XprType> class TensorConversionOp;
 template<typename Dimensions, typename InputXprType, typename KernelXprType> class TensorConvolutionOp;
 template<typename PatchDim, typename XprType> class TensorPatchOp;
 template<DenseIndex Rows, DenseIndex Cols, typename XprType> class TensorImagePatchOp;