Compute Library
 21.08
Unstack.cpp
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24 #include "Unstack.h"
25 
27 
28 namespace arm_compute
29 {
30 namespace test
31 {
32 namespace validation
33 {
34 namespace reference
35 {
36 namespace
37 {
38 inline Coordinates expand_coordinates(Coordinates in_coord, size_t axis, size_t slice, size_t num_dimensions)
39 {
40  /*
41  Reconstruct input_coord to read the corresponding value from the correct slice. This is done by adding an extra dimension
42  to the coordinates and shuffling around the values based on the info below.
43 
44  For example, if input tensor shape is (X, Y, Z, W);
45 
46  If axis == 0, each slice will have the shape (Y, Z, W) and there will be X slices
47 
48  If axis == 1, each slice will have the shape (X, Z, W) and there will be Y slices.
49  */
50  Coordinates expanded_coord;
51  expanded_coord.set_num_dimensions(num_dimensions);
52  expanded_coord.set(axis, slice);
53  for(size_t k = 0; k < axis; ++k)
54  {
55  expanded_coord.set(k, in_coord[k]);
56  }
57  for(size_t k = axis + 1; k < num_dimensions; ++k)
58  {
59  expanded_coord.set(k, in_coord[k - 1]);
60  }
61  return expanded_coord;
62 }
63 
64 template <typename T>
65 SimpleTensor<T> get_slice(const SimpleTensor<T> &input_tensor, size_t axis, size_t slice)
66 {
67  TensorShape out_shape = input_tensor.shape();
68  out_shape.remove_dimension(axis);
69 
70  const size_t unpacked_num_dimensions(input_tensor.shape().num_dimensions());
71 
72  SimpleTensor<T> output{ out_shape, input_tensor.data_type() };
73 
74  Window win;
75  win.use_tensor_dimensions(out_shape);
76  execute_window_loop(win, [&](const Coordinates & id)
77  {
78  const Coordinates input_coords = expand_coordinates(id, axis, slice, unpacked_num_dimensions);
79  *reinterpret_cast<T *>(output(id)) = *reinterpret_cast<const T *>(input_tensor(input_coords));
80  });
81 
82  return output;
83 }
84 } // namespace
85 
86 template <typename T>
87 std::vector<SimpleTensor<T>> unstack(const SimpleTensor<T> &input_tensor, std::vector<SimpleTensor<T>> &output_tensors, int axis)
88 {
89  // Wrap around negative values
90  const unsigned int axis_u = wrap_around(axis, static_cast<int>(input_tensor.shape().num_dimensions()));
91  ARM_COMPUTE_ERROR_ON(axis_u >= input_tensor.shape().num_dimensions());
92  for(size_t k = 0; k < output_tensors.size(); ++k)
93  {
94  SimpleTensor<T> &output = output_tensors[k];
95  const SimpleTensor<T> kth_slice = get_slice(input_tensor, axis_u, k);
96  output = copy_tensor<T>(kth_slice);
97  }
98  return output_tensors;
99 }
100 
101 template std::vector<SimpleTensor<float>> unstack(const SimpleTensor<float> &input_tensor, std::vector<SimpleTensor<float>> &output_tensors, int axis);
102 template std::vector<SimpleTensor<half>> unstack(const SimpleTensor<half> &input_tensor, std::vector<SimpleTensor<half>> &output_tensors, int axis);
103 template std::vector<SimpleTensor<uint8_t>> unstack(const SimpleTensor<uint8_t> &input_tensor, std::vector<SimpleTensor<uint8_t>> &output_tensors, int axis);
104 
105 } // namespace reference
106 } // namespace validation
107 } // namespace test
108 } // namespace arm_compute
std::vector< SimpleTensor< T > > unstack(const SimpleTensor< T > &input_tensor, std::vector< SimpleTensor< T >> &output_tensors, int axis)
Definition: Unstack.cpp:87
#define ARM_COMPUTE_ERROR_ON(cond)
If the condition is true then an error message is printed and an exception thrown.
Definition: Error.h:466
TensorShape shape() const override
Shape of the tensor.
Definition: SimpleTensor.h:320
Copyright (c) 2017-2021 Arm Limited.
T wrap_around(T x, T m)
Wrap-around a number within the range 0 <= x < m.
Definition: Helpers.h:231
Simple tensor object that stores elements in a consecutive chunk of memory.
Definition: SimpleTensor.h:58
void execute_window_loop(const Window &w, L &&lambda_function, Ts &&... iterators)
Iterate through the passed window, automatically adjusting the iterators and calling the lambda_funct...
Definition: Helpers.inl:77
SimpleTensor< T > slice(const SimpleTensor< T > &src, Coordinates starts, Coordinates ends)