COMPMID-1726: Implement CLUnstack.

Change-Id: I94b0707d19757c5f5d7ca66d9c47e378867126a3
Reviewed-on: https://review.mlplatform.org/325
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>

1 files changed, 108 insertions, 0 deletions

diff --git a/tests/validation/reference/Unstack.cpp b/tests/validation/reference/Unstack.cpp
new file mode 100644
index 0000000000..3474c15173
--- /dev/null
+++ b/tests/validation/reference/Unstack.cpp
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2018 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "Unstack.h"
+
+#include "tests/validation/Helpers.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+namespace
+{
+inline Coordinates expand_coordinates(Coordinates in_coord, size_t axis, size_t slice, size_t num_dimensions)
+{
+    /*
+        Reconstruct input_coord to read the corresponding value from the correct slice. This is done by adding an extra dimension
+        to the coordinates and shuffling around the values based on the info below.
+
+        For example, if input tensor shape is (X, Y, Z, W);
+
+        If axis == 0, each slice will have the shape (Y, Z, W) and there will be X slices
+
+        If axis == 1, each slice will have the shape (X, Z, W) and there will be Y slices.
+    */
+    Coordinates expanded_coord;
+    expanded_coord.set_num_dimensions(num_dimensions);
+    expanded_coord.set(axis, slice);
+    for(size_t k = 0; k < axis; ++k)
+    {
+        expanded_coord.set(k, in_coord[k]);
+    }
+    for(size_t k = axis + 1; k < num_dimensions; ++k)
+    {
+        expanded_coord.set(k, in_coord[k - 1]);
+    }
+    return expanded_coord;
+}
+
+template <typename T>
+SimpleTensor<T> get_slice(const SimpleTensor<T> &input_tensor, size_t axis, size_t slice)
+{
+    TensorShape out_shape = input_tensor.shape();
+    out_shape.remove_dimension(axis);
+
+    const size_t unpacked_num_dimensions(input_tensor.shape().num_dimensions());
+
+    SimpleTensor<T> output{ out_shape, input_tensor.data_type() };
+
+    Window win;
+    win.use_tensor_dimensions(out_shape);
+    execute_window_loop(win, [&](const Coordinates & id)
+    {
+        const Coordinates input_coords     = expand_coordinates(id, axis, slice, unpacked_num_dimensions);
+        *reinterpret_cast<T *>(output(id)) = *reinterpret_cast<const T *>(input_tensor(input_coords));
+    });
+
+    return output;
+}
+} // namespace
+
+template <typename T>
+std::vector<SimpleTensor<T>> unstack(const SimpleTensor<T> &input_tensor, std::vector<SimpleTensor<T>> &output_tensors, int axis)
+{
+    // Wrap around negative values
+    const unsigned int axis_u = wrap_around(axis, static_cast<int>(input_tensor.shape().num_dimensions()));
+    ARM_COMPUTE_ERROR_ON(axis_u >= input_tensor.shape().num_dimensions());
+    for(size_t k = 0; k < output_tensors.size(); ++k)
+    {
+        SimpleTensor<T>      &output    = output_tensors[k];
+        const SimpleTensor<T> kth_slice = get_slice(input_tensor, axis_u, k);
+        output                          = copy_tensor<T>(kth_slice);
+    }
+    return output_tensors;
+}
+
+template std::vector<SimpleTensor<float>> unstack(const SimpleTensor<float> &input_tensor, std::vector<SimpleTensor<float>> &output_tensors, int axis);
+template std::vector<SimpleTensor<half>> unstack(const SimpleTensor<half> &input_tensor, std::vector<SimpleTensor<half>> &output_tensors, int axis);
+template std::vector<SimpleTensor<uint8_t>> unstack(const SimpleTensor<uint8_t> &input_tensor, std::vector<SimpleTensor<uint8_t>> &output_tensors, int axis);
+
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute