From 1c879eb010df8e53e5ac016ee5d155db2c721c2b Mon Sep 17 00:00:00 2001 From: Eugene Zhulenev Date: Tue, 10 Dec 2019 15:40:23 -0800 Subject: Remove V2 suffix from TensorBlock --- unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h | 1481 ++++++++++++++++++++++ 1 file changed, 1481 insertions(+) create mode 100644 unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h (limited to 'unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h') diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h b/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h new file mode 100644 index 000000000..222333847 --- /dev/null +++ b/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h @@ -0,0 +1,1481 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// 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_BLOCK_H +#define EIGEN_CXX11_TENSOR_TENSOR_BLOCK_H + +namespace Eigen { +namespace internal { + +// -------------------------------------------------------------------------- // +// Forward declarations for templates defined below. +template +class TensorBlockIO; + +// -------------------------------------------------------------------------- // +// Helper function to compute strides for densely stored buffer of given +// dimensions. + +// TODO(ezhulenev): We compute strides 1000 times in different evaluators, use +// this function instead everywhere. +template +EIGEN_ALWAYS_INLINE DSizes strides( + const DSizes& dimensions) { + DSizes strides; + if (NumDims == 0) return strides; + + // TODO(ezhulenev): Use templates to unroll this loop (similar to + // h_array_reduce in CXX11meta.h)? Benchmark it. + if (static_cast(Layout) == static_cast(ColMajor)) { + strides[0] = 1; + for (int i = 1; i < NumDims; ++i) { + strides[i] = strides[i - 1] * dimensions[i - 1]; + } + } else { + strides[NumDims - 1] = 1; + for (int i = NumDims - 2; i >= 0; --i) { + strides[i] = strides[i + 1] * dimensions[i + 1]; + } + } + + return strides; +} + +template +EIGEN_ALWAYS_INLINE DSizes strides( + const Eigen::array& dimensions) { + return strides(DSizes(dimensions)); +} + +template +EIGEN_STRONG_INLINE DSizes strides( + const Sizes& sizes) { + return strides(DSizes(sizes)); +} + +// -------------------------------------------------------------------------- // + +// Tensor block shape type defines what are the shape preference for the blocks +// extracted from the larger tensor. +// +// Example: blocks of 100 elements from the large 100x100 tensor: +// - tensor: 100x100 +// - target_block_size: 100 +// +// TensorBlockShapeType: +// - kUniformAllDims: 100 blocks of size 10x10 +// - kSkewedInnerDims: 100 blocks of size 100x1 (or 1x100 depending on a column +// or row major layout) +enum class TensorBlockShapeType { kUniformAllDims, kSkewedInnerDims }; + +struct TensorBlockResourceRequirements { + TensorBlockShapeType shape_type; + size_t size; + + EIGEN_DEVICE_FUNC + static EIGEN_STRONG_INLINE TensorBlockResourceRequirements + merge(const TensorBlockResourceRequirements &lhs, + const TensorBlockResourceRequirements &rhs) { + return {merge(lhs.shape_type, rhs.shape_type), merge(rhs.size, lhs.size)}; + } + + // This is a resource requirement that should be returned from expressions + // that do not have any block evaluation preference (e.g. default tensor + // expression with raw buffer access). + EIGEN_DEVICE_FUNC + static EIGEN_STRONG_INLINE TensorBlockResourceRequirements any() { + return {TensorBlockShapeType::kUniformAllDims, 1}; + } + +private: + using Requirements = TensorBlockResourceRequirements; + + EIGEN_DEVICE_FUNC + static EIGEN_STRONG_INLINE size_t merge(size_t lhs_size, size_t rhs_size) { + return numext::maxi(lhs_size, rhs_size); + } + + EIGEN_DEVICE_FUNC + static EIGEN_STRONG_INLINE TensorBlockShapeType merge(TensorBlockShapeType lhs, + TensorBlockShapeType rhs) { + return (lhs == TensorBlockShapeType::kSkewedInnerDims || + rhs == TensorBlockShapeType::kSkewedInnerDims) + ? TensorBlockShapeType::kSkewedInnerDims + : TensorBlockShapeType::kUniformAllDims; + } +}; + +// -------------------------------------------------------------------------- // +// TensorBlockDescriptor specifies a block offset within a tensor and the block +// sizes along each of the tensor dimensions. + +template +class TensorBlockDescriptor { + public: + typedef DSizes Dimensions; + + // If we evaluate a Tensor assignment, and expression on the left, already has + // a memory buffer, then we might do performance optimization, and evaluate + // the root expression directly into the final output memory. Some time it's + // possible to reuse it for materializing subexpressions inside an expression + // tree, to to avoid dynamic memory allocation. + // + // The pointer type of the underlying storage is erased, because passing + // Scalar type through all the expression evaluation layers is way too many + // templates. In practice destination buffer type should always match the + // evaluated expression scalar type. + class DestinationBuffer { + public: + enum DestinationBufferKind : int { + // The above explicit specification of "int" as the enum basetype is needed + // to get around a HIPCC link error ("the field type is not amp-compatible") + // which is issued for class members with the enum type. + // TODO(rocm): + // remove the "int" basetype once HIPCC has been fixed to not error out + // in the above scenario. + + // Destination buffer is not defined (`m_data` == nullptr). + kEmpty, + + // Tensor block defined by an owning tensor block descriptor can fit + // contiguously into the destination buffer. In this case it's safe to + // materialize tensor block in the destination buffer, wrap it in a + // TensorMap, and use to build Eigen expression on top of it. + kContiguous, + + // Destination buffer strides do not match strides of the contiguously + // stored block, and it's impossible to define a TensorMap over this + // buffer. However if we are evaluating a root of an expression tree, we + // still can materialize an output into this destination, because we can + // guarantee that no one will ever access it through block API. + // + // In theory it is possible to build valid TensorStriding + // expression on top of this destination buffer, however it has + // inefficient coeff/packet access, and defeats the purpose of fast block + // evaluation API. + kStrided + }; + + template + Scalar* data() const { + eigen_assert(m_data_type_size == sizeof(Scalar)); + return static_cast(m_data); + } + + const Dimensions& strides() const { return m_strides; } + const DestinationBufferKind& kind() const { return m_kind; } + + private: + friend class TensorBlockDescriptor; + + DestinationBuffer() : m_data(NULL), m_data_type_size(0), m_kind(kEmpty) {} + + template + DestinationBuffer(Scalar* data, const Dimensions& strides, + DestinationBufferKind kind) + : m_data(static_cast(data)), + m_data_type_size(sizeof(Scalar)), + m_strides(strides), + m_kind(kind) {} + + template + static DestinationBuffer make(const TensorBlockDescriptor& desc, + Scalar* data, const Dimensions& strides) { + return DestinationBuffer(data, strides, kind(desc, strides)); + } + + template + static DestinationBufferKind kind(const TensorBlockDescriptor& desc, + const Dimensions& strides) { + const Dimensions& desc_dims = desc.dimensions(); + const Dimensions& desc_strides = internal::strides(desc_dims); + for (int i = 0; i < NumDims; ++i) { + if (desc_dims[i] == 1) continue; + if (desc_strides[i] != strides[i]) return kStrided; + } + return kContiguous; + } + + // Storage pointer is type erased, to reduce template bloat, but we still + // keep the size of the underlying element type for error checking. + void* m_data; + size_t m_data_type_size; + + // Destination buffer dimensions always match the dimensions of a tensor + // block descriptor it belongs to, however strides might be different. + Dimensions m_strides; + + DestinationBufferKind m_kind; + }; + + TensorBlockDescriptor(const IndexType offset, const Dimensions& dimensions, + const DestinationBuffer& destination) + : m_offset(offset), + m_dimensions(dimensions), + m_destination(destination) {} + + TensorBlockDescriptor(const IndexType offset, const Dimensions& dimensions) + : m_offset(offset), + m_dimensions(dimensions), + m_destination(DestinationBuffer()) {} + + IndexType offset() const { return m_offset; } + const Dimensions& dimensions() const { return m_dimensions; } + IndexType dimension(int index) const { return m_dimensions[index]; } + IndexType size() const { return array_prod(m_dimensions); } + + const DestinationBuffer& destination() const { return m_destination; } + + template + void AddDestinationBuffer(Scalar* dst_base, const Dimensions& dst_strides) { + eigen_assert(dst_base != NULL); + m_destination = + DestinationBuffer::template make(*this, dst_base, dst_strides); + } + + template + void AddDestinationBuffer( + Scalar* dst_base, + const DSizes& dst_strides) { + // DSizes constructor will do index type promotion if it's safe. + AddDestinationBuffer(dst_base, Dimensions(dst_strides)); + } + + TensorBlockDescriptor& DropDestinationBuffer() { + m_destination.m_data = NULL; + m_destination.m_kind = DestinationBuffer::kEmpty; + return *this; + } + + bool HasDestinationBuffer() const { + return m_destination.kind() != DestinationBuffer::kEmpty; + } + + // Returns a copy of `*this` with updated offset. + TensorBlockDescriptor WithOffset(IndexType offset) const { + return TensorBlockDescriptor(offset, m_dimensions, m_destination); + } + + private: + // Offset and dimensions are immutable after construction. Block descriptor + // can only be mutated by adding or dropping destination. + const IndexType m_offset; + const Dimensions m_dimensions; + DestinationBuffer m_destination; +}; + +// -------------------------------------------------------------------------- // +// TensorBlockMapper is responsible for iterating over the blocks of a tensor. + +template +class TensorBlockMapper { + typedef TensorBlockDescriptor BlockDescriptor; + + public: + typedef DSizes Dimensions; + + TensorBlockMapper() = default; + TensorBlockMapper(const DSizes& dimensions, + const TensorBlockResourceRequirements& requirements) + : m_tensor_dimensions(dimensions), m_requirements(requirements) { + // Initialize `m_block_dimensions`. + InitializeBlockDimensions(); + + // Calculate block counts by dimension and total block count. + DSizes block_count; + for (int i = 0; i < NumDims; ++i) { + block_count[i] = divup(m_tensor_dimensions[i], m_block_dimensions[i]); + } + m_total_block_count = array_prod(block_count); + + // Calculate block strides (used for enumerating blocks). + m_tensor_strides = strides(m_tensor_dimensions); + m_block_strides = strides(block_count); + } + + EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE IndexType blockCount() const { + return m_total_block_count; + } + + EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE IndexType blockTotalSize() const { + return m_block_dimensions.TotalSize(); + } + + EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const DSizes& + blockDimensions() const { + return m_block_dimensions; + } + + EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE + BlockDescriptor blockDescriptor(IndexType block_index) const { + static const bool isColMajor = Layout == static_cast(ColMajor); + + IndexType offset = 0; + DSizes dimensions; + + if (NumDims == 0) return BlockDescriptor(offset, dimensions); + + // Iterate outer -> inner dimensions. + for (int i = NumDims - 1; i >= 0; --i) { + const int dim = isColMajor ? i : NumDims - i - 1; + + const IndexType idx = block_index / m_block_strides[dim]; + block_index -= idx * m_block_strides[dim]; + + const IndexType coord = idx * m_block_dimensions[dim]; + dimensions[dim] = numext::mini(m_tensor_dimensions[dim] - coord, + m_block_dimensions[dim]); + offset += coord * m_tensor_strides[dim]; + } + + return {offset, dimensions}; + } + + private: + void InitializeBlockDimensions() { + // Requested block shape and size. + const TensorBlockShapeType shape_type = m_requirements.shape_type; + const IndexType target_block_size = + numext::maxi(1, static_cast(m_requirements.size)); + + // Corner case: one of the dimensions is zero. Logic below is too complex + // to handle this case on a general basis, just use unit block size. + // Note: we must not yield blocks with zero dimensions (recipe for + // overflows/underflows, divisions by zero and NaNs later). + if (m_tensor_dimensions.TotalSize() == 0) { + for (int i = 0; i < NumDims; ++i) { + m_block_dimensions[i] = 1; + } + return; + } + + // If tensor fits into a target block size, evaluate it as a single block. + if (m_tensor_dimensions.TotalSize() <= target_block_size) { + m_block_dimensions = m_tensor_dimensions; + return; + } + + static const bool isColMajor = Layout == static_cast(ColMajor); + + // Block shape skewed towards inner dimension. + if (shape_type == TensorBlockShapeType::kSkewedInnerDims) { + IndexType coeff_to_allocate = target_block_size; + + for (int i = 0; i < NumDims; ++i) { + const int dim = isColMajor ? i : NumDims - i - 1; + m_block_dimensions[dim] = + numext::mini(coeff_to_allocate, m_tensor_dimensions[dim]); + coeff_to_allocate = divup( + coeff_to_allocate, + numext::maxi(static_cast(1), m_block_dimensions[dim])); + } + eigen_assert(coeff_to_allocate == 1); + + } else if (shape_type == TensorBlockShapeType::kUniformAllDims) { + // Tensor will not fit within 'target_block_size' budget: calculate tensor + // block dimension sizes based on "square" dimension size target. + const IndexType dim_size_target = convert_index( + std::pow(static_cast(target_block_size), + 1.0f / static_cast(m_block_dimensions.rank()))); + + for (int i = 0; i < NumDims; ++i) { + // TODO(andydavis) Adjust the inner most 'block_dim_size' to make it + // a multiple of the packet size. Note that reducing + // 'block_dim_size' in this manner can increase the number of + // blocks, and so will amplify any per-block overhead. + m_block_dimensions[i] = + numext::mini(dim_size_target, m_tensor_dimensions[i]); + } + + // Add any un-allocated coefficients to inner dimension(s). + IndexType total_size = m_block_dimensions.TotalSize(); + for (int i = 0; i < NumDims; ++i) { + const int dim = isColMajor ? i : NumDims - i - 1; + + if (m_block_dimensions[dim] < m_tensor_dimensions[dim]) { + const IndexType total_size_other_dims = + total_size / m_block_dimensions[dim]; + const IndexType alloc_avail = + divup(target_block_size, total_size_other_dims); + if (alloc_avail == m_block_dimensions[dim]) { + // Insufficient excess coefficients to allocate. + break; + } + m_block_dimensions[dim] = + numext::mini(m_tensor_dimensions[dim], alloc_avail); + total_size = total_size_other_dims * m_block_dimensions[dim]; + } + } + + } else { + eigen_assert(false); // unknown block shape + } + + eigen_assert(m_block_dimensions.TotalSize() >= + numext::mini(target_block_size, + m_tensor_dimensions.TotalSize())); + } + + DSizes m_tensor_dimensions; + TensorBlockResourceRequirements m_requirements; + + DSizes m_block_dimensions; + IndexType m_total_block_count; + + DSizes m_tensor_strides; + DSizes m_block_strides; +}; + +// -------------------------------------------------------------------------- // +// TensorBlockScratchAllocator is responsible for allocating temporary buffers +// for block evaluation (output or input block materialization). Given that +// Eigen expression traversal order is deterministic, all temporary allocations +// are happening in the same order, and usually have exactly the same size. +// Scratch allocator keeps a trace of all dynamic allocations, and after the +// first block evaluation is completed, we should be able to reuse all the +// temporary buffers for the next block evaluation. + +template +class TensorBlockScratchAllocator { + public: + explicit TensorBlockScratchAllocator(const Device& device) + : m_device(device), m_allocation_index(0) {} + + ~TensorBlockScratchAllocator() { + for (size_t i = 0; i < m_allocations.size(); ++i) { + m_device.deallocate(m_allocations[i].ptr); + } + } + + void* allocate(size_t size) { + // TODO(ezhulenev): Remove when replaced with inlined vector. + if (m_allocations.capacity() == 0) m_allocations.reserve(8); + + // Check if we already have an existing allocation att current index. + const int num_allocations = static_cast(m_allocations.size()); + const bool has_allocation = m_allocation_index < num_allocations; + + // Allocation index can't be larger than the number of allocations. + eigen_assert(m_allocation_index <= num_allocations); + + // If we have existing allocation, and its size is larger or equal to + // requested size, we do nothing. + + // If current allocation can't fit requested size, we deallocate it, and + // replace with a larger allocation. + if (has_allocation && m_allocations[m_allocation_index].size < size) { + m_device.deallocate(m_allocations[m_allocation_index].ptr); + m_allocations[m_allocation_index].ptr = m_device.allocate(size); + m_allocations[m_allocation_index].size = size; + } + + // Make a new allocation if we don't have and existing one. + if (!has_allocation) { + Allocation allocation; + allocation.ptr = m_device.allocate(size); + allocation.size = size; + m_allocations.push_back(allocation); + } + + eigen_assert(m_allocations[m_allocation_index].ptr != NULL); + eigen_assert(m_allocations[m_allocation_index].size >= size); + + return m_allocations[m_allocation_index++].ptr; + } + + void reset() { m_allocation_index = 0; } + + private: + struct Allocation { + void* ptr; + size_t size; + }; + + const Device& m_device; + int m_allocation_index; + // TODO(ezhulenev): This should be an inlined vector. + std::vector m_allocations; +}; + +// -------------------------------------------------------------------------- // +// TensorBlockKind represents all possible block kinds, that can be produced by +// TensorEvaluator::evalBlock function. +enum TensorBlockKind { + // Tensor block that is a lazy expression that must be assigned to a + // destination using TensorBlockAssign. + kExpr, + + // Tensor block that is a view into a memory buffer owned by an underlying + // Tensor expression (e.g. it can be a view into a Tensor buffer). + kView, + + // Tensor block that was materialized in a scratch memory buffer, allocated + // with TensorBlockScratchAllocator. This block must be copied to a + // destination, similar to a block of `kExpr` type. + kMaterializedInScratch, + + // Tensor block that was materialized directly into the final output memory + // buffer. For example if the left side of an assignment is a Tensor, we can + // directly materialize the block in the destination memory. + // + // If strides in the output buffer do not match tensor block strides, the + // Tensor expression will be invalid, and should not be used by + // TensorBlockAssign or for constructing another block expression. + kMaterializedInOutput +}; + +// -------------------------------------------------------------------------- // +// TensorBlockNotImplemented should be used to defined TensorBlock typedef in +// TensorEvaluators that do not support block evaluation. + +class TensorBlockNotImplemented { + public: + typedef void XprType; +}; + +// -------------------------------------------------------------------------- // +// XprScalar extracts Scalar type from the Eigen expressions (if expression type +// is not void). It's required to be able to define lazy block expression for +// argument types, that do not support block evaluation. + +template +struct XprScalar { + typedef typename XprType::Scalar type; +}; +template <> +struct XprScalar { + typedef void type; +}; + +// -------------------------------------------------------------------------- // +// TensorMaterializedBlock is a fully evaluated block of the original tensor, +// and XprType is just a TensorMap over the data. This block type is typically +// used to materialize blocks of tensor expressions, that can't be efficiently +// represented as lazy Tensor expressions with fast coeff/packet operations, +// e.g. we materialize all broadcasts into evaluated blocks. +// +// TensorMaterializedBlock does not own its memory buffer, it's either a memory +// buffer that backs the original expression (e.g. block is just a view into a +// Tensor), or a memory buffer allocated with scratch allocator, and in this +// case the scratch allocator will deallocate it at the end of block based +// expression execution. +// +// If the block was evaluated directly into the output buffer, and strides in +// the output buffer do not match block strides, the TensorMap expression will +// be invalid, and should never be used in block assignment or any other tensor +// expression. + +template +class TensorMaterializedBlock { + public: + typedef DSizes Dimensions; + typedef TensorMap > XprType; + + TensorMaterializedBlock(TensorBlockKind kind, const Scalar* data, + const Dimensions& dimensions, bool valid_expr = true) + : m_kind(kind), + m_data(data), + m_dimensions(dimensions), + m_expr(m_data, m_dimensions), + m_valid_expr(valid_expr) { + eigen_assert(m_kind == internal::TensorBlockKind::kView || + m_kind == internal::TensorBlockKind::kMaterializedInScratch || + m_kind == internal::TensorBlockKind::kMaterializedInOutput); + } + + TensorBlockKind kind() const { return m_kind; } + // NOTE(ezhulenev): Returning XprType by value like in other block types + // causes asan failures. The theory is that XprType::Nested doesn't work + // properly for TensorMap. + const XprType& expr() const { + eigen_assert(m_valid_expr); + return m_expr; + } + const Scalar* data() const { return m_data; } + void cleanup() {} + + typedef internal::TensorBlockDescriptor TensorBlockDesc; + + // TensorMaterializedBlock can be backed by different types of storage: + // + // (1) Contiguous block of memory allocated with scratch allocator. + // (2) Contiguous block of memory reused from tensor block descriptor + // destination buffer. + // (3) Strided block of memory reused from tensor block descriptor + // destination buffer. + // + class Storage { + public: + Scalar* data() const { return m_data; } + const Dimensions& dimensions() const { return m_dimensions; } + const Dimensions& strides() const { return m_strides; } + + TensorMaterializedBlock AsTensorMaterializedBlock() const { + return TensorMaterializedBlock( + m_materialized_in_output + ? internal::TensorBlockKind::kMaterializedInOutput + : internal::TensorBlockKind::kMaterializedInScratch, + m_data, m_dimensions, !m_strided_storage); + } + + private: + friend class TensorMaterializedBlock; + + Storage(Scalar* data, const Dimensions& dimensions, + const Dimensions& strides, bool materialized_in_output, + bool strided_storage) + : m_data(data), + m_dimensions(dimensions), + m_strides(strides), + m_materialized_in_output(materialized_in_output), + m_strided_storage(strided_storage) {} + + Scalar* m_data; + Dimensions m_dimensions; + Dimensions m_strides; + bool m_materialized_in_output; + bool m_strided_storage; + }; + + // Creates a storage for materialized block either from the block descriptor + // destination buffer, or allocates a new buffer with scratch allocator. + template + EIGEN_STRONG_INLINE static Storage prepareStorage( + TensorBlockDesc& desc, TensorBlockScratch& scratch, + bool allow_strided_storage = false) { + // Try to reuse destination as an output block buffer. + typedef typename TensorBlockDesc::DestinationBuffer DestinationBuffer; + + if (desc.destination().kind() == DestinationBuffer::kContiguous) { + Scalar* buffer = desc.destination().template data(); + desc.DropDestinationBuffer(); + return Storage(buffer, desc.dimensions(), + internal::strides(desc.dimensions()), + /*materialized_in_output=*/true, + /*strided_storage=*/false); + + } else if (desc.destination().kind() == DestinationBuffer::kStrided && + allow_strided_storage) { + Scalar* buffer = desc.destination().template data(); + desc.DropDestinationBuffer(); + return Storage(buffer, desc.dimensions(), desc.destination().strides(), + /*materialized_in_output=*/true, /*strided_storage=*/true); + + } else { + void* mem = scratch.allocate(desc.size() * sizeof(Scalar)); + return Storage(static_cast(mem), desc.dimensions(), + internal::strides(desc.dimensions()), + /*materialized_in_output=*/false, + /*strided_storage=*/false); + } + } + + // Creates a materialized block for the given descriptor from a memory buffer. + template + EIGEN_STRONG_INLINE static TensorMaterializedBlock materialize( + const Scalar* data, const DataDimensions& data_dims, + TensorBlockDesc& desc, TensorBlockScratch& scratch) { + eigen_assert(array_size::value == desc.dimensions().size()); + + // If a tensor block dimensions covers a contiguous block of the underlying + // memory, we can skip block buffer memory allocation, and construct a block + // from existing `data` memory buffer. + // + // Example: (RowMajor layout) + // data_dims: [11, 12, 13, 14] + // desc.dimensions(): [1, 1, 3, 14] + // + // In this case we can construct a TensorBlock starting at + // `data + desc.offset()`, with a `desc.dimensions()` block sizes. + static const bool is_col_major = Layout == ColMajor; + + // Find out how many inner dimensions have a matching size. + int num_matching_inner_dims = 0; + for (int i = 0; i < NumDims; ++i) { + int dim = is_col_major ? i : NumDims - i - 1; + if (data_dims[dim] != desc.dimensions()[dim]) break; + ++num_matching_inner_dims; + } + + // All the outer dimensions must be of size `1`, except a single dimension + // before the matching inner dimension (`3` in the example above). + bool can_use_direct_access = true; + for (int i = num_matching_inner_dims + 1; i < NumDims; ++i) { + int dim = is_col_major ? i : NumDims - i - 1; + if (desc.dimension(dim) != 1) { + can_use_direct_access = false; + break; + } + } + + if (can_use_direct_access) { + const Scalar* block_start = data + desc.offset(); + return TensorMaterializedBlock(internal::TensorBlockKind::kView, + block_start, desc.dimensions()); + + } else { + // Reuse destination buffer or allocate new buffer with scratch allocator. + const Storage storage = prepareStorage(desc, scratch); + + typedef internal::TensorBlockIO + TensorBlockIO; + typedef typename TensorBlockIO::Dst TensorBlockIODst; + typedef typename TensorBlockIO::Src TensorBlockIOSrc; + + TensorBlockIOSrc src(internal::strides(Dimensions(data_dims)), + data, desc.offset()); + TensorBlockIODst dst(storage.dimensions(), storage.strides(), + storage.data()); + + TensorBlockIO::Copy(dst, src); + return storage.AsTensorMaterializedBlock(); + } + } + + private: + TensorBlockKind m_kind; + const Scalar* m_data; + Dimensions m_dimensions; + XprType m_expr; + bool m_valid_expr; +}; + +// -------------------------------------------------------------------------- // +// TensorCwiseUnaryBlock is a lazy tensor expression block that applies UnaryOp +// functor to the blocks produced by the underlying Tensor expression. + +template +class TensorCwiseUnaryBlock { + + static const bool NoArgBlockAccess = + internal::is_void::value; + + public: + typedef typename conditional< + NoArgBlockAccess, void, + TensorCwiseUnaryOp >:: + type XprType; + + typedef typename XprScalar::type Scalar; + + TensorCwiseUnaryBlock(const ArgTensorBlock& arg_block, const UnaryOp& functor) + : m_arg_block(arg_block), m_functor(functor) {} + + TensorBlockKind kind() const { return internal::TensorBlockKind::kExpr; } + + XprType expr() const { return XprType(m_arg_block.expr(), m_functor); } + const Scalar* data() const { return NULL; } + void cleanup() { m_arg_block.cleanup(); } + + private: + ArgTensorBlock m_arg_block; + UnaryOp m_functor; +}; + +// -------------------------------------------------------------------------- // +// TensorCwiseUnaryBlock is a lazy tensor expression block that applies BinaryOp +// functor to the blocks produced by the underlying Tensor expression. + +template +class TensorCwiseBinaryBlock { + + static const bool NoArgBlockAccess = + internal::is_void::value || + internal::is_void::value; + + public: + typedef typename conditional< + NoArgBlockAccess, void, + TensorCwiseBinaryOp >::type + XprType; + + typedef typename XprScalar::type Scalar; + + TensorCwiseBinaryBlock(const LhsTensorBlock& left_block, + const RhsTensorBlock& right_block, + const BinaryOp& functor) + : m_left_block(left_block), + m_right_block(right_block), + m_functor(functor) {} + + TensorBlockKind kind() const { return internal::TensorBlockKind::kExpr; } + + XprType expr() const { + return XprType(m_left_block.expr(), m_right_block.expr(), m_functor); + } + + const Scalar* data() const { return NULL; } + + void cleanup() { + m_left_block.cleanup(); + m_right_block.cleanup(); + } + + private: + LhsTensorBlock m_left_block; + RhsTensorBlock m_right_block; + BinaryOp m_functor; +}; + +// -------------------------------------------------------------------------- // +// TensorUnaryExprBlock is a lazy tensor expression block that can construct +// an arbitrary tensor expression from a block of the underlying type (this is a +// generalization of the TensorCwiseUnaryBlock for arbitrary expressions). + +template +class TensorUnaryExprBlock { + + typedef typename ArgTensorBlock::XprType ArgXprType; + static const bool NoArgBlockAccess = internal::is_void::value; + + public: + typedef typename conditional< + NoArgBlockAccess, void, + typename BlockFactory::template XprType::type>::type XprType; + + typedef typename XprScalar::type Scalar; + + TensorUnaryExprBlock(const ArgTensorBlock& arg_block, + const BlockFactory& factory) + : m_arg_block(arg_block), m_factory(factory) {} + + TensorBlockKind kind() const { return internal::TensorBlockKind::kExpr; } + XprType expr() const { return m_factory.expr(m_arg_block.expr()); } + const Scalar* data() const { return NULL; } + void cleanup() { m_arg_block.cleanup(); } + + private: + ArgTensorBlock m_arg_block; + BlockFactory m_factory; +}; + +// -------------------------------------------------------------------------- // +// TensorTernaryExprBlock is a lazy tensor expression block that can construct +// an arbitrary tensor expression from three blocks of the underlying type. + +template +class TensorTernaryExprBlock { + + typedef typename Arg1TensorBlock::XprType Arg1XprType; + typedef typename Arg2TensorBlock::XprType Arg2XprType; + typedef typename Arg3TensorBlock::XprType Arg3XprType; + + static const bool NoArgBlockAccess = internal::is_void::value || + internal::is_void::value || + internal::is_void::value; + + public: + typedef typename conditional< + NoArgBlockAccess, void, + typename BlockFactory::template XprType::type>::type XprType; + + typedef typename XprScalar::type Scalar; + + TensorTernaryExprBlock(const Arg1TensorBlock& arg1_block, + const Arg2TensorBlock& arg2_block, + const Arg3TensorBlock& arg3_block, + const BlockFactory& factory) + : m_arg1_block(arg1_block), + m_arg2_block(arg2_block), + m_arg3_block(arg3_block), + m_factory(factory) {} + + TensorBlockKind kind() const { return internal::TensorBlockKind::kExpr; } + XprType expr() const { + return m_factory.expr(m_arg1_block.expr(), m_arg2_block.expr(), + m_arg3_block.expr()); + } + const Scalar* data() const { return NULL; } + void cleanup() { + m_arg1_block.cleanup(); + m_arg2_block.cleanup(); + m_arg3_block.cleanup(); + } + + private: + Arg1TensorBlock m_arg1_block; + Arg2TensorBlock m_arg2_block; + Arg3TensorBlock m_arg3_block; + BlockFactory m_factory; +}; + +// -------------------------------------------------------------------------- // +// StridedLinearBufferCopy provides a method to copy data between two linear +// buffers with different strides, with optimized paths for scatter/gather. + +template +class StridedLinearBufferCopy { + typedef typename packet_traits::type Packet; + enum { + Vectorizable = packet_traits::Vectorizable, + PacketSize = packet_traits::size + }; + + public: + // Specifying linear copy kind statically gives ~30% speedup for small sizes. + enum Kind { + Linear = 0, // src_stride == 1 && dst_stride == 1 + Scatter = 1, // src_stride == 1 && dst_stride != 1 + FillLinear = 2, // src_stride == 0 && dst_stride == 1 + FillScatter = 3, // src_stride == 0 && dst_stride != 1 + Gather = 4, // dst_stride == 1 + Random = 5 // everything else + }; + + struct Dst { + Dst(IndexType o, IndexType s, Scalar* d) : offset(o), stride(s), data(d) {} + + IndexType offset; + IndexType stride; + Scalar* data; + }; + + struct Src { + Src(IndexType o, IndexType s, const Scalar* d) + : offset(o), stride(s), data(d) {} + + IndexType offset; + IndexType stride; + const Scalar* data; + }; + + template + static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void Run(const Dst& dst, + const Src& src, + const size_t count) { + Run(count, dst.offset, dst.stride, dst.data, src.offset, src.stride, + src.data); + } + + private: + template + static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void Run( + const IndexType count, const IndexType dst_offset, + const IndexType dst_stride, Scalar* EIGEN_RESTRICT dst_data, + const IndexType src_offset, const IndexType src_stride, + const Scalar* EIGEN_RESTRICT src_data) { + const Scalar* src = &src_data[src_offset]; + Scalar* dst = &dst_data[dst_offset]; + + if (!Vectorizable) { + for (Index i = 0; i < count; ++i) { + dst[i * dst_stride] = src[i * src_stride]; + } + return; + } + + const IndexType vectorized_size = count - PacketSize; + IndexType i = 0; + + if (kind == Linear) { + // ******************************************************************** // + // Linear copy from `src` to `dst`. + const IndexType unrolled_size = count - 4 * PacketSize; + eigen_assert(src_stride == 1 && dst_stride == 1); + for (; i <= unrolled_size; i += 4 * PacketSize) { + for (int j = 0; j < 4; ++j) { + Packet p = ploadu(src + i + j * PacketSize); + pstoreu(dst + i + j * PacketSize, p); + } + } + for (; i <= vectorized_size; i += PacketSize) { + Packet p = ploadu(src + i); + pstoreu(dst + i, p); + } + for (; i < count; ++i) { + dst[i] = src[i]; + } + // ******************************************************************** // + } else if (kind == Scatter) { + // Scatter from `src` to `dst`. + eigen_assert(src_stride == 1 && dst_stride != 1); + for (; i <= vectorized_size; i += PacketSize) { + Packet p = ploadu(src + i); + pscatter(dst + i * dst_stride, p, dst_stride); + } + for (; i < count; ++i) { + dst[i * dst_stride] = src[i]; + } + // ******************************************************************** // + } else if (kind == FillLinear) { + // Fill `dst` with value at `*src`. + eigen_assert(src_stride == 0 && dst_stride == 1); + const IndexType unrolled_size = count - 4 * PacketSize; + Packet p = pload1(src); + for (; i <= unrolled_size; i += 4 * PacketSize) { + for (int j = 0; j < 4; ++j) { + pstoreu(dst + i + j * PacketSize, p); + } + } + for (; i <= vectorized_size; i += PacketSize) { + pstoreu(dst + i, p); + } + for (; i < count; ++i) { + dst[i] = *src; + } + // ******************************************************************** // + } else if (kind == FillScatter) { + // Scatter `*src` into `dst`. + eigen_assert(src_stride == 0 && dst_stride != 1); + Packet p = pload1(src); + for (; i <= vectorized_size; i += PacketSize) { + pscatter(dst + i * dst_stride, p, dst_stride); + } + for (; i < count; ++i) { + dst[i * dst_stride] = *src; + } + // ******************************************************************** // + } else if (kind == Gather) { + // Gather from `src` into `dst`. + eigen_assert(dst_stride == 1); + for (; i <= vectorized_size; i += PacketSize) { + Packet p = pgather(src + i * src_stride, src_stride); + pstoreu(dst + i, p); + } + for (; i < count; ++i) { + dst[i] = src[i * src_stride]; + } + // ******************************************************************** // + } else if (kind == Random) { + // Random. + for (; i < count; ++i) { + dst[i * dst_stride] = src[i * src_stride]; + } + } else { + eigen_assert(false); + } + } +}; + +// -------------------------------------------------------------------------- // +// TensorBlockIO copies data from `src` tensor block, to the `dst` tensor block. +// It's possible to specify src->dst dimension mapping for the copy operation. +// Dimensions of `dst` specify how many elements have to be copied, for the +// `src` we need to know only stride to navigate through source memory buffer. + +template +class TensorBlockIO { + static const bool IsColMajor = (Layout == ColMajor); + + typedef StridedLinearBufferCopy LinCopy; + + public: + typedef DSizes Dimensions; + typedef DSizes DimensionsMap; + + struct Dst { + Dst(const Dimensions& dst_dims, const Dimensions& dst_strides, Scalar* dst, + IndexType dst_offset = 0) + : dims(dst_dims), strides(dst_strides), data(dst), offset(dst_offset) {} + + Dimensions dims; + Dimensions strides; + Scalar* data; + IndexType offset; + }; + + struct Src { + Src(const Dimensions& src_strides, const Scalar* src, + IndexType src_offset = 0) + : strides(src_strides), data(src), offset(src_offset) {} + + Dimensions strides; + const Scalar* data; + IndexType offset; + }; + + // Copies data to `dst` from `src`, using provided dimensions mapping: + // + // src_dimension_index = dst_to_src_dim_map[dst_dimension_index] + // + // Returns the number of copied elements. + static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE IndexType Copy( + const Dst& dst, const Src& src, const DimensionsMap& dst_to_src_dim_map) { + // Copy single scalar value from `src` to `dst`. + if (NumDims == 0) { + *(dst.data + dst.offset) = *(src.data + src.offset); + return 1; + } + + // Both `dst` and `src` must have contiguous innermost dimension. We also + // accept the special case with stride '0', because it's used as a trick to + // implement broadcasting. + { + int inner_dim = IsColMajor ? 0 : NumDims - 1; + EIGEN_UNUSED_VARIABLE(inner_dim); + eigen_assert(dst.strides[inner_dim] == 1 || dst.strides[inner_dim] == 0); + eigen_assert(src.strides[inner_dim] == 1 || src.strides[inner_dim] == 0); + } + + // Give a shorter name to `dst_to_src_dim_map`. + const DimensionsMap& dim_map = dst_to_src_dim_map; + + // Do not squeeze reordered inner dimensions. + int num_squeezable_dims = NumSqueezableInnerDims(dim_map); + + // NOTE: We find the innermost dimension (contiguous in memory) in the dst + // block, and we write data linearly into that dimension, reading it from + // the src. If dimensions are reordered, we might end up reading data from + // the src with `stride != 1`. + // + // NOTE: Random-Read/Linear-Write can be up to ~2X faster than + // Linear-Read/Random-Write: https://stackoverflow.com/a/54935680 + + // Find the innermost dimension in the dst whose size is not 1. This is the + // effective inner dim. + int num_size_one_inner_dims = 0; + for (int i = 0; i < num_squeezable_dims; ++i) { + const int dst_dim = IsColMajor ? i : NumDims - i - 1; + if (dst.dims[dst_dim] != 1) break; + num_size_one_inner_dims++; + } + + // If all dimensions are of size 1, just copy a scalar from `src` to `dst`. + if (num_size_one_inner_dims == NumDims) { + *(dst.data + dst.offset) = *(src.data + src.offset); + return 1; + } + + // Outermost dimension in the dst with `stride == 1` (contiguous in memory). + const int dst_stride1_dim = IsColMajor + ? num_size_one_inner_dims + : NumDims - num_size_one_inner_dims - 1; + + // Dimension in the src that corresponds to the dst innermost dimension. + const int src_dim_for_dst_stride1_dim = + NumDims == 0 ? 1 : dim_map[dst_stride1_dim]; + + // Size of the innermost dimension (length of contiguous blocks of memory). + IndexType dst_inner_dim_size = NumDims == 0 ? 1 : dst.dims[dst_stride1_dim]; + + // Squeeze multiple inner dims into one if they are contiguous in `dst` and + // `src` memory, so we can do less linear copy calls. + for (int i = num_size_one_inner_dims + 1; i < num_squeezable_dims; ++i) { + const int dst_dim = IsColMajor ? i : NumDims - i - 1; + const IndexType dst_stride = dst.strides[dst_dim]; + const IndexType src_stride = src.strides[dim_map[dst_dim]]; + if (dst_inner_dim_size == dst_stride && dst_stride == src_stride) { + dst_inner_dim_size *= dst.dims[dst_dim]; + ++num_size_one_inner_dims; + } else { + break; + } + } + + // Setup strides to read data from `src` and write to `dst`. + IndexType input_offset = src.offset; + IndexType output_offset = dst.offset; + IndexType input_stride = + NumDims == 0 ? 1 : src.strides[src_dim_for_dst_stride1_dim]; + IndexType output_stride = NumDims == 0 ? 1 : dst.strides[dst_stride1_dim]; + + const int at_least_1_dim = NumDims <= 1 ? 1 : NumDims - 1; + array it; + + // Initialize block iterator state. Squeeze away any dimension of size 1. + int idx = 0; // currently initialized iterator state index + for (int i = num_size_one_inner_dims; i < NumDims - 1; ++i) { + const int dst_dim = IsColMajor ? i + 1 : NumDims - i - 2; + if (dst.dims[dst_dim] == 1) continue; + + it[idx].size = dst.dims[dst_dim]; + it[idx].input_stride = src.strides[dim_map[dst_dim]]; + it[idx].output_stride = dst.strides[dst_dim]; + + it[idx].input_span = it[idx].input_stride * (it[idx].size - 1); + it[idx].output_span = it[idx].output_stride * (it[idx].size - 1); + + idx++; + } + + // Iterate copying data from src to dst. + const IndexType block_total_size = NumDims == 0 ? 1 : dst.dims.TotalSize(); + +#define COPY_INNER_DIM(KIND) \ + IndexType num_copied = 0; \ + for (num_copied = 0; num_copied < block_total_size; \ + num_copied += dst_inner_dim_size) { \ + LinCopy::template Run( \ + typename LinCopy::Dst(output_offset, output_stride, dst.data), \ + typename LinCopy::Src(input_offset, input_stride, src.data), \ + dst_inner_dim_size); \ + \ + for (int j = 0; j < idx; ++j) { \ + if (++it[j].count < it[j].size) { \ + input_offset += it[j].input_stride; \ + output_offset += it[j].output_stride; \ + break; \ + } \ + it[j].count = 0; \ + input_offset -= it[j].input_span; \ + output_offset -= it[j].output_span; \ + } \ + } \ + return num_copied; + + if (input_stride == 1 && output_stride == 1) { + COPY_INNER_DIM(LinCopy::Linear); + } else if (input_stride == 1 && output_stride != 1) { + COPY_INNER_DIM(LinCopy::Scatter); + } else if (input_stride == 0 && output_stride == 1) { + COPY_INNER_DIM(LinCopy::FillLinear); + } else if (input_stride == 0 && output_stride != 1) { + COPY_INNER_DIM(LinCopy::FillScatter); + } else if (output_stride == 1) { + COPY_INNER_DIM(LinCopy::Gather); + } else { + COPY_INNER_DIM(LinCopy::Random); + } + +#undef COPY_INNER_DIM + } + + // Copy from `src` to `dst` with an identity src->dst dimension map. Returns + // the number of copied elements. + static EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE IndexType Copy(const Dst& dst, + const Src& src) { + DimensionsMap dst_to_src_map; + for (int i = 0; i < NumDims; ++i) dst_to_src_map[i] = i; + return Copy(dst, src, dst_to_src_map); + } + + private: + struct BlockIteratorState { + BlockIteratorState() + : size(0), + count(0), + input_stride(0), + output_stride(0), + input_span(0), + output_span(0) {} + + IndexType size; + IndexType count; + IndexType input_stride; + IndexType output_stride; + IndexType input_span; + IndexType output_span; + }; + + // Compute how many inner dimensions it's allowed to squeeze when doing IO + // between two tensor blocks. It's safe to squeeze inner dimensions, only + // if they are not reordered. + static int NumSqueezableInnerDims(const DimensionsMap& dim_map) { + int num_squeezable_dims = 0; + for (int i = 0; i < NumDims; ++i) { + const int dim = IsColMajor ? i : NumDims - i - 1; + if (dim_map[dim] != dim) break; + num_squeezable_dims++; + } + return num_squeezable_dims; + } +}; + +// -------------------------------------------------------------------------- // +// TensorBlockAssignment assigns a block expression of type `TensorBlockExpr` to +// a Tensor block defined by `desc`, backed by a memory buffer at `target`. +// +// Currently there is no way to write from a Tensor expression to a block of +// memory, if dimensions are reordered. If you need to do that, you should +// materialize a Tensor block expression into a memory buffer, and then use +// TensorBlockIO to copy data between two memory buffers with a custom +// `target->src` dimension map (see definition above). +// +// Also currently the innermost dimension of `target` must have a stride '1' +// (contiguous in memory). This restriction could be lifted with a `pscatter`, +// but in practice it's never needed, and there is a similar TensorBlockIO +// workaround for that. +// +// TODO(ezhulenev): TensorBlockAssignment is a special case of TensorBlockIO +// where `src` is a tensor expression. Explore if it is possible to rewrite IO +// to use expressions instead of pointers, and after that TensorBlockAssignment +// will become an alias to IO. +template +class TensorBlockAssignment { + // We will use coeff/packet path to evaluate block expressions. + typedef TensorEvaluator + TensorBlockEvaluator; + + typedef DSizes Dimensions; + + enum { + Vectorizable = packet_traits::Vectorizable, + PacketSize = packet_traits::size + }; + + template + struct InnerDimAssign { + EIGEN_ALWAYS_INLINE static void Run(Scalar* target, IndexType count, + const Evaluator& eval, + IndexType eval_offset) { + for (IndexType i = 0; i < count; ++i) { + target[i] = eval.coeff(eval_offset + i); + } + } + }; + + template + struct InnerDimAssign { + EIGEN_ALWAYS_INLINE static void Run(Scalar* target, IndexType count, + const Evaluator& eval, + IndexType eval_offset) { + typedef typename packet_traits::type Packet; + + const IndexType unrolled_size = count - 4 * PacketSize; + const IndexType vectorized_size = count - PacketSize; + IndexType i = 0; + + for (; i <= unrolled_size; i += 4 * PacketSize) { + for (int j = 0; j < 4; ++j) { + const IndexType idx = eval_offset + i + j * PacketSize; + Packet p = eval.template packet(idx); + pstoreu(target + i + j * PacketSize, p); + } + } + + for (; i <= vectorized_size; i += PacketSize) { + Packet p = eval.template packet(eval_offset + i); + pstoreu(target + i, p); + } + + for (; i < count; ++i) { + target[i] = eval.coeff(eval_offset + i); + } + } + }; + + public: + struct Target { + Target(const Dimensions& target_dims, const Dimensions& target_strides, + Scalar* target_data, IndexType target_offset = 0) + : dims(target_dims), + strides(target_strides), + data(target_data), + offset(target_offset) {} + + Dimensions dims; + Dimensions strides; + Scalar* data; + IndexType offset; + }; + + static Target target(const Dimensions& target_dims, + const Dimensions& target_strides, Scalar* target_data, + IndexType target_offset = 0) { + return Target(target_dims, target_strides, target_data, target_offset); + } + + template + static Target target( + const DSizes& target_dims, + const DSizes& target_strides, + Scalar* target_data, IndexType target_offset = 0) { + // DSizes constructor will do index type promotion if it's safe. + return Target(Dimensions(target_dims), Dimensions(target_strides), + target_data, target_offset); + } + + static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void Run( + const Target& target, const TensorBlockExpr& expr) { + // Prepare evaluator for block expression. + DefaultDevice default_device; + TensorBlockEvaluator eval(expr, default_device); + + // Tensor block expression dimension should match destination dimensions. + eigen_assert(dimensions_match(target.dims, eval.dimensions())); + + static const int Layout = TensorBlockEvaluator::Layout; + static const bool is_col_major = Layout == ColMajor; + + // Initialize output inner dimension size based on a layout. + const IndexType output_size = NumDims == 0 ? 1 : target.dims.TotalSize(); + const int inner_dim_idx = is_col_major ? 0 : NumDims - 1; + IndexType output_inner_dim_size = target.dims[inner_dim_idx]; + + // Target inner dimension stride must be '1'. + eigen_assert(target.strides[inner_dim_idx] == 1); + + // Squeeze multiple inner dims into one if they are contiguous in `target`. + IndexType num_squeezed_dims = 0; + for (Index i = 1; i < NumDims; ++i) { + const Index dim = is_col_major ? i : NumDims - i - 1; + const IndexType target_stride = target.strides[dim]; + + if (output_inner_dim_size == target_stride) { + output_inner_dim_size *= target.dims[dim]; + num_squeezed_dims++; + } else { + break; + } + } + + // Initialize output block iterator state. Dimension in this array are + // always in inner_most -> outer_most order (col major layout). + array it; + + int idx = 0; // currently initialized iterator state index + for (Index i = num_squeezed_dims; i < NumDims - 1; ++i) { + const Index dim = is_col_major ? i + 1 : NumDims - i - 2; + + it[idx].count = 0; + it[idx].size = target.dims[dim]; + it[idx].output_stride = target.strides[dim]; + it[idx].output_span = it[idx].output_stride * (it[idx].size - 1); + idx++; + } + + // We read block expression from the beginning, and start writing data to + // `target` at given offset. + IndexType input_offset = 0; + IndexType output_offset = target.offset; + + // Iterate copying data from `eval` to `target`. + for (IndexType i = 0; i < output_size; i += output_inner_dim_size) { + // Assign to `target` at current offset. + InnerDimAssign::Run(target.data + output_offset, + output_inner_dim_size, eval, + input_offset); + + // Move input offset forward by the number of assigned coefficients. + input_offset += output_inner_dim_size; + + // Update index. + for (int j = 0; j < idx; ++j) { + if (++it[j].count < it[j].size) { + output_offset += it[j].output_stride; + break; + } + it[j].count = 0; + output_offset -= it[j].output_span; + } + } + } + + private: + struct BlockIteratorState { + BlockIteratorState() + : count(0), size(0), output_stride(0), output_span(0) {} + + IndexType count; + IndexType size; + IndexType output_stride; + IndexType output_span; + }; +}; + +// -------------------------------------------------------------------------- // + +} // namespace internal +} // namespace Eigen + +#endif // EIGEN_CXX11_TENSOR_TENSOR_BLOCK_H -- cgit v1.2.3