Template Class TensorBatchWrap

Class Documentation

template<typename T, int... Strides>
class TensorBatchWrap

TensorBatchWrap class is a non-owning wrap of a batch of N-D tensors used for easy access of its elements in CUDA device.

TensorBatchWrap is a wrapper of a batch of multi-dimensional tensors that can have one or more of its N dimension strides, or pitches, defined either at compile-time or at run-time. Each pitch in Strides represents the offset in bytes as a compile-time template parameter that will be applied from the first (slowest changing) dimension to the last (fastest changing) dimension of the tensor, in that order. Each dimension with run-time pitch is specified as -1 in the Strides template parameter.

Template arguments:

  • T type of the values inside the tensors

  • Strides sequence of compile- or run-time pitches (-1 indicates run-time)

    • Y compile-time pitches

    • X run-time pitches

    • N dimensions, where N = X + Y

For example, in the code below a wrap is defined for a batch of HWC 3D tensors where each row in H has a run-time row pitch (second -1), a pixel in W has a compile-time constant pitch as the size of the pixel type and a channel in C has also a compile-time constant pitch as the size of the channel type.

using DataType = ...;
using ChannelType = BaseType<DataType>;
using TensorBatchWrap = TensorBatchWrap<ChannelType, -1, sizeof(DataType), sizeof(ChannelType)>;
TensorBatch tensorBatch = ...;
TensorBatchWrap tensorBatchWrap(tensorBatch.data());
// Elements may be accessed via operator[] using an int4 argument.  They can also be accessed via pointer using
// the ptr method with up to 4 integer arguments or by accessing each TensorWrap separately with tensor(...) method.

TensorBatch wrapper class specialized for non-constant value type.

Template Parameters:
  • T – Type (it can be const) of each element inside the tensor wrapper.

  • Strides – Each compile-time (use -1 for run-time) pitch in bytes from first to last dimension.

  • T – Type (non-const) of each element inside the tensor batch wrapper.

  • Strides – Each compile-time (use -1 for run-time) pitch in bytes from first to last dimension.

Public Types

using ValueType = T

Public Functions

inline __host__ TensorBatchWrap(const TensorBatchDataStridedCuda &data)

Constructs a TensorBatchWrap by wrapping a data argument.

Parameters:

data[in] Tensor batch data to wrap.

inline __host__ __device__ TensorBatchWrap (NVCVTensorBatchData &data)

Constructs a TensorBatchWrap by wrapping a data argument.

Parameters:

data[in] Tensor batch data to wrap.

template<typename... Coords> inline __host__ __device__ T * ptr (int t, Coords... c) const

Get a read-and-write proxy (as pointer) of the given tensor at the given coordinates.

Parameters:
  • t[in] Tensor index in the list.

  • c[in] Coordinates in the given tensor;

Returns:

The const pointer to the beginning of the given coordinates.

inline __host__ __device__ auto tensor (int t) const

Constructs a read-and-write wrapper for the tensor on index t The list of static strides can be provided as a template parameter. It should be a list of N outer strides (from inner to outer).

Template Parameters:

Strides – static strides

Parameters:

t – index of the tensor

template<typename DimType, class = Require<std::is_same_v<int, BaseType<DimType>>>> inline __host__ __device__ T & operator[] (DimType c) const

Subscript operator for read-and-write access.

Parameters:
  • t[in] Tensor index in the list.

  • c[in] (N+1)-D coordinates - tensor index and coords (from inner to outer) to be accessed. E.g. for a 2-dimensional tensors, the coordinates would be: {tensor_id, column, row}

Returns:

Accessed reference.

template<typename... Args> inline __host__ __device__ T * doGetPtr (int t, Args... c) const
inline const __host__ __device__ int64_t * strides (int t) const

Returns a pointer to a stride buffer of the tensor at index t.

Parameters:

t – tensor index

Public Members

NVCVTensorBatchElementStridedRec *m_tensors

Public Static Attributes

static constexpr int kNumDimensions