From f697df723798779bc29d9f7299bb5398767d5db0 Mon Sep 17 00:00:00 2001
From: Benoit Steiner <benoit.steiner.goog@gmail.com>
Date: Wed, 14 Jan 2015 15:38:48 -0800
Subject: Improved support for RowMajor tensors Misc fixes and API cleanups.

---
 .../Eigen/CXX11/src/Tensor/TensorStriding.h        | 175 +++++++++++++++++----
 1 file changed, 148 insertions(+), 27 deletions(-)

(limited to 'unsupported/Eigen/CXX11/src/Tensor/TensorStriding.h')

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorStriding.h b/unsupported/Eigen/CXX11/src/Tensor/TensorStriding.h
index ecfdb762c..2fbdfadfe 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorStriding.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorStriding.h
@@ -24,11 +24,14 @@ template<typename Strides, typename XprType>
 struct traits<TensorStridingOp<Strides, XprType> > : public traits<XprType>
 {
   typedef typename XprType::Scalar Scalar;
-  typedef typename internal::packet_traits<Scalar>::type Packet;
-  typedef typename traits<XprType>::StorageKind StorageKind;
-  typedef typename traits<XprType>::Index Index;
+  typedef traits<XprType> XprTraits;
+  typedef typename packet_traits<Scalar>::type Packet;
+  typedef typename XprTraits::StorageKind StorageKind;
+  typedef typename XprTraits::Index Index;
   typedef typename XprType::Nested Nested;
   typedef typename remove_reference<Nested>::type _Nested;
+  static const int NumDimensions = XprTraits::NumDimensions;
+  static const int Layout = XprTraits::Layout;
 };
 
 template<typename Strides, typename XprType>
@@ -98,6 +101,8 @@ struct TensorEvaluator<const TensorStridingOp<Strides, ArgType>, Device>
   enum {
     IsAligned = /*TensorEvaluator<ArgType, Device>::IsAligned*/false,
     PacketAccess = TensorEvaluator<ArgType, Device>::PacketAccess,
+    Layout = TensorEvaluator<ArgType, Device>::Layout,
+    CoordAccess = false,  // to be implemented
   };
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorEvaluator(const XprType& op, const Device& device)
@@ -109,14 +114,25 @@ struct TensorEvaluator<const TensorStridingOp<Strides, ArgType>, Device>
     }
 
     const typename TensorEvaluator<ArgType, Device>::Dimensions& input_dims = m_impl.dimensions();
-    m_outputStrides[0] = 1;
-    m_inputStrides[0] = 1;
-    for (int i = 1; i < NumDims; ++i) {
-      m_outputStrides[i] = m_outputStrides[i-1] * m_dimensions[i-1];
-      m_inputStrides[i] = m_inputStrides[i-1] * input_dims[i-1];
-      m_inputStrides[i-1] *= op.strides()[i-1];
+    if (Layout == ColMajor) {
+      m_outputStrides[0] = 1;
+      m_inputStrides[0] = 1;
+      for (int i = 1; i < NumDims; ++i) {
+        m_outputStrides[i] = m_outputStrides[i-1] * m_dimensions[i-1];
+        m_inputStrides[i] = m_inputStrides[i-1] * input_dims[i-1];
+        m_inputStrides[i-1] *= op.strides()[i-1];
+      }
+      m_inputStrides[NumDims-1] *= op.strides()[NumDims-1];
+    } else {  // RowMajor
+      m_outputStrides[NumDims-1] = 1;
+      m_inputStrides[NumDims-1] = 1;
+      for (int i = NumDims - 2; i >= 0; --i) {
+        m_outputStrides[i] = m_outputStrides[i+1] * m_dimensions[i+1];
+        m_inputStrides[i] = m_inputStrides[i+1] * input_dims[i+1];
+        m_inputStrides[i+1] *= op.strides()[i+1];
+      }
+      m_inputStrides[0] *= op.strides()[0];
     }
-    m_inputStrides[NumDims-1] *= op.strides()[NumDims-1];
   }
 
   typedef typename XprType::Scalar Scalar;
@@ -135,14 +151,7 @@ struct TensorEvaluator<const TensorStridingOp<Strides, ArgType>, Device>
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CoeffReturnType coeff(Index index) const
   {
-    Index inputIndex = 0;
-    for (int i = NumDims - 1; i > 0; --i) {
-      const Index idx = index / m_outputStrides[i];
-      inputIndex += idx * m_inputStrides[i];
-      index -= idx * m_outputStrides[i];
-    }
-    inputIndex += index * m_inputStrides[0];
-    return m_impl.coeff(inputIndex);
+    return m_impl.coeff(srcCoeff(index));
   }
 
   template<int LoadMode>
@@ -154,16 +163,29 @@ struct TensorEvaluator<const TensorStridingOp<Strides, ArgType>, Device>
 
     Index inputIndices[] = {0, 0};
     Index indices[] = {index, index + packetSize - 1};
-    for (int i = NumDims - 1; i > 0; --i) {
-      const Index idx0 = indices[0] / m_outputStrides[i];
-      const Index idx1 = indices[1] / m_outputStrides[i];
-      inputIndices[0] += idx0 * m_inputStrides[i];
-      inputIndices[1] += idx1 * m_inputStrides[i];
-      indices[0] -= idx0 * m_outputStrides[i];
-      indices[1] -= idx1 * m_outputStrides[i];
+    if (Layout == ColMajor) {
+      for (int i = NumDims - 1; i > 0; --i) {
+        const Index idx0 = indices[0] / m_outputStrides[i];
+        const Index idx1 = indices[1] / m_outputStrides[i];
+        inputIndices[0] += idx0 * m_inputStrides[i];
+        inputIndices[1] += idx1 * m_inputStrides[i];
+        indices[0] -= idx0 * m_outputStrides[i];
+        indices[1] -= idx1 * m_outputStrides[i];
+      }
+      inputIndices[0] += indices[0] * m_inputStrides[0];
+      inputIndices[1] += indices[1] * m_inputStrides[0];
+    } else {  // RowMajor
+      for (int i = 0; i < NumDims - 1; ++i) {
+        const Index idx0 = indices[0] / m_outputStrides[i];
+        const Index idx1 = indices[1] / m_outputStrides[i];
+        inputIndices[0] += idx0 * m_inputStrides[i];
+        inputIndices[1] += idx1 * m_inputStrides[i];
+        indices[0] -= idx0 * m_outputStrides[i];
+        indices[1] -= idx1 * m_outputStrides[i];
+      }
+      inputIndices[0] += indices[0] * m_inputStrides[NumDims-1];
+      inputIndices[1] += indices[1] * m_inputStrides[NumDims-1];
     }
-    inputIndices[0] += indices[0] * m_inputStrides[0];
-    inputIndices[1] += indices[1] * m_inputStrides[0];
     if (inputIndices[1] - inputIndices[0] == packetSize - 1) {
       PacketReturnType rslt = m_impl.template packet<Unaligned>(inputIndices[0]);
       return rslt;
@@ -183,6 +205,27 @@ struct TensorEvaluator<const TensorStridingOp<Strides, ArgType>, Device>
   Scalar* data() const { return NULL; }
 
  protected:
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Index srcCoeff(Index index) const
+  {
+    Index inputIndex = 0;
+    if (Layout == ColMajor) {
+      for (int i = NumDims - 1; i > 0; --i) {
+        const Index idx = index / m_outputStrides[i];
+        inputIndex += idx * m_inputStrides[i];
+        index -= idx * m_outputStrides[i];
+      }
+      inputIndex += index * m_inputStrides[0];
+    } else {  // RowMajor
+      for (int i = 0; i < NumDims - 1; ++i) {
+        const Index idx = index / m_outputStrides[i];
+        inputIndex += idx * m_inputStrides[i];
+        index -= idx * m_outputStrides[i];
+      }
+      inputIndex += index * m_inputStrides[NumDims-1];
+    }
+    return inputIndex;
+  }
+
   Dimensions m_dimensions;
   array<Index, NumDims> m_outputStrides;
   array<Index, NumDims> m_inputStrides;
@@ -190,6 +233,84 @@ struct TensorEvaluator<const TensorStridingOp<Strides, ArgType>, Device>
 };
 
 
+// Eval as lvalue
+template<typename Strides, typename ArgType, typename Device>
+struct TensorEvaluator<TensorStridingOp<Strides, ArgType>, Device>
+    : public TensorEvaluator<const TensorStridingOp<Strides, ArgType>, Device>
+{
+  typedef TensorStridingOp<Strides, ArgType> XprType;
+  typedef TensorEvaluator<const XprType, Device> Base;
+  //  typedef typename XprType::Index Index;
+  static const int NumDims = internal::array_size<typename TensorEvaluator<ArgType, Device>::Dimensions>::value;
+  //  typedef DSizes<Index, NumDims> Dimensions;
+
+  enum {
+    IsAligned = /*TensorEvaluator<ArgType, Device>::IsAligned*/false,
+    PacketAccess = TensorEvaluator<ArgType, Device>::PacketAccess,
+    Layout = TensorEvaluator<ArgType, Device>::Layout,
+    CoordAccess = false,  // to be implemented
+  };
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorEvaluator(const XprType& op, const Device& device)
+      : Base(op, device) { }
+
+  typedef typename XprType::Index Index;
+  typedef typename XprType::Scalar Scalar;
+  typedef typename XprType::PacketReturnType PacketReturnType;
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Scalar& coeffRef(Index index)
+  {
+    return this->m_impl.coeffRef(this->srcCoeff(index));
+  }
+
+  template <int StoreMode> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  void writePacket(Index index, const PacketReturnType& x)
+  {
+    const int packetSize = internal::unpacket_traits<PacketReturnType>::size;
+    EIGEN_STATIC_ASSERT(packetSize > 1, YOU_MADE_A_PROGRAMMING_MISTAKE)
+    eigen_assert(index+packetSize-1 < this->dimensions().TotalSize());
+
+    Index inputIndices[] = {0, 0};
+    Index indices[] = {index, index + packetSize - 1};
+    if (Layout == ColMajor) {
+      for (int i = NumDims - 1; i > 0; --i) {
+        const Index idx0 = indices[0] / this->m_outputStrides[i];
+        const Index idx1 = indices[1] / this->m_outputStrides[i];
+        inputIndices[0] += idx0 * this->m_inputStrides[i];
+        inputIndices[1] += idx1 * this->m_inputStrides[i];
+        indices[0] -= idx0 * this->m_outputStrides[i];
+        indices[1] -= idx1 * this->m_outputStrides[i];
+      }
+      inputIndices[0] += indices[0] * this->m_inputStrides[0];
+      inputIndices[1] += indices[1] * this->m_inputStrides[0];
+    } else {  // RowMajor
+      for (int i = 0; i < NumDims - 1; ++i) {
+        const Index idx0 = indices[0] / this->m_outputStrides[i];
+        const Index idx1 = indices[1] / this->m_outputStrides[i];
+        inputIndices[0] += idx0 * this->m_inputStrides[i];
+        inputIndices[1] += idx1 * this->m_inputStrides[i];
+        indices[0] -= idx0 * this->m_outputStrides[i];
+        indices[1] -= idx1 * this->m_outputStrides[i];
+      }
+      inputIndices[0] += indices[0] * this->m_inputStrides[NumDims-1];
+      inputIndices[1] += indices[1] * this->m_inputStrides[NumDims-1];
+    }
+    if (inputIndices[1] - inputIndices[0] == packetSize - 1) {
+      this->m_impl.template writePacket<Unaligned>(inputIndices[0], x);
+    }
+    else {
+      EIGEN_ALIGN_DEFAULT Scalar values[packetSize];
+      internal::pstore<Scalar, PacketReturnType>(values, x);
+      this->m_impl.coeffRef(inputIndices[0]) = values[0];
+      this->m_impl.coeffRef(inputIndices[1]) = values[packetSize-1];
+      for (int i = 1; i < packetSize-1; ++i) {
+        this->coeffRef(index+i) = values[i];
+      }
+    }
+  }
+};
+
+
 } // end namespace Eigen
 
 #endif // EIGEN_CXX11_TENSOR_TENSOR_STRIDING_H
-- 
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