COMPMID-1461 SSD support: Create NEON PriorBox

Change-Id: I99e1c3939cfea4b9cb0ddfa313706f31b213ca89
diff --git a/src/core/NEON/kernels/NEPriorBoxLayerKernel.cpp b/src/core/NEON/kernels/NEPriorBoxLayerKernel.cpp
new file mode 100644
index 0000000..2f63179
--- /dev/null
+++ b/src/core/NEON/kernels/NEPriorBoxLayerKernel.cpp
@@ -0,0 +1,358 @@
+/*
+ * 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 "arm_compute/core/NEON/kernels/NEPriorBoxLayerKernel.h"
+
+#include "arm_compute/core/Helpers.h"
+#include "arm_compute/core/ITensor.h"
+#include "arm_compute/core/Types.h"
+#include "arm_compute/core/Validate.h"
+
+#include <arm_neon.h>
+#include <cstdint>
+
+namespace arm_compute
+{
+namespace
+{
+Status validate_arguments(const ITensorInfo *input1, const ITensorInfo *input2, const ITensorInfo *output, const PriorBoxLayerInfo &info)
+{
+    ARM_COMPUTE_RETURN_ERROR_ON_NULLPTR(input1, input2, output);
+    ARM_COMPUTE_RETURN_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(input1, 1, DataType::F32);
+    ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_LAYOUT(input1, input2);
+    ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_TYPES(input1, input2);
+
+    // Check variances
+    const int var_size = info.variances().size();
+    if(var_size > 1)
+    {
+        ARM_COMPUTE_RETURN_ERROR_ON_MSG(var_size != 4, "Must provide 4 variance values");
+        for(int i = 0; i < var_size; ++i)
+        {
+            ARM_COMPUTE_RETURN_ERROR_ON_MSG(var_size <= 0, "Must be greater than 0");
+        }
+    }
+    ARM_COMPUTE_RETURN_ERROR_ON_MSG(info.steps()[0] < 0.f, "Step x should be greater or equal to 0");
+    ARM_COMPUTE_RETURN_ERROR_ON_MSG(info.steps()[1] < 0.f, "Step y should be greater or equal to 0");
+
+    if(!info.max_sizes().empty())
+    {
+        ARM_COMPUTE_RETURN_ERROR_ON_MSG(info.max_sizes().size() != info.min_sizes().size(), "Max and min sizes dimensions should match");
+    }
+
+    for(unsigned int i = 0; i < info.max_sizes().size(); ++i)
+    {
+        ARM_COMPUTE_RETURN_ERROR_ON_MSG(info.max_sizes()[i] < info.min_sizes()[i], "Max size should be greater than min size");
+    }
+
+    if(output != nullptr && output->total_size() != 0)
+    {
+        ARM_COMPUTE_RETURN_ERROR_ON(output->dimension(get_data_layout_dimension_index(input1->data_layout(), DataLayoutDimension::HEIGHT)) != 2);
+        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_LAYOUT(input1, output);
+    }
+
+    return Status{};
+}
+
+std::pair<Status, Window> validate_and_configure_window(const ITensorInfo *input1, const ITensorInfo *input2, ITensorInfo *output, const PriorBoxLayerInfo &info)
+{
+    ARM_COMPUTE_UNUSED(input2);
+
+    Window win            = {};
+    bool   window_changed = false;
+    switch(input1->data_layout())
+    {
+        case DataLayout::NCHW:
+        {
+            const int          num_priors                        = info.aspect_ratios().size() * info.min_sizes().size() + info.max_sizes().size();
+            const unsigned int num_elems_processed_per_iteration = 4 * num_priors;
+            win                                                  = calculate_max_window(*output, Steps(num_elems_processed_per_iteration));
+            AccessWindowHorizontal output_access(output, 0, num_elems_processed_per_iteration);
+            window_changed = update_window_and_padding(win, output_access);
+            break;
+        }
+        case DataLayout::NHWC:
+        {
+            win = calculate_max_window(*output, Steps());
+            break;
+        }
+        default:
+            ARM_COMPUTE_ERROR("Not implemented");
+    };
+
+    Status err = (window_changed) ? ARM_COMPUTE_CREATE_ERROR(ErrorCode::RUNTIME_ERROR, "Insufficient Padding!") : Status{};
+    return std::make_pair(err, win);
+}
+} // namespace
+
+NEPriorBoxLayerKernel::NEPriorBoxLayerKernel()
+    : _func(nullptr), _input1(nullptr), _input2(nullptr), _output(nullptr), _info()
+{
+}
+
+template <DataLayout DL>
+void NEPriorBoxLayerKernel::store_coordinates(float *out, const int offset, const float center_x, const float center_y, const float box_width, const float box_height, const int width,
+                                              const int height)
+{
+    float xmin = (center_x - box_width / 2.f) / width;
+    float ymin = (center_y - box_height / 2.f) / height;
+    float xmax = (center_x + box_width / 2.f) / width;
+    float ymax = (center_y + box_height / 2.f) / height;
+
+    switch(DL)
+    {
+        case DataLayout::NCHW:
+        {
+            float32x4_t vec_elements = { xmin, ymin, xmax, ymax };
+            if(_info.clip())
+            {
+                static const float32x4_t CONST_0 = vdupq_n_f32(0.f);
+                static const float32x4_t CONST_1 = vdupq_n_f32(1.f);
+                vec_elements                     = vmaxq_f32(vminq_f32(vec_elements, CONST_1), CONST_0);
+            }
+            vst1q_f32(out + offset, vec_elements);
+        }
+        break;
+        case DataLayout::NHWC:
+        {
+            const int output_offset = _output->info()->strides_in_bytes()[1] / _output->info()->element_size();
+            if(_info.clip())
+            {
+                xmin = std::min(std::max(xmin, 0.f), 1.f);
+                ymin = std::min(std::max(ymin, 0.f), 1.f);
+                xmax = std::min(std::max(xmax, 0.f), 1.f);
+                ymax = std::min(std::max(ymax, 0.f), 1.f);
+            }
+
+            *(out + output_offset * offset)       = xmin;
+            *(out + output_offset * (offset + 1)) = ymin;
+            *(out + output_offset * (offset + 2)) = xmax;
+            *(out + output_offset * (offset + 3)) = ymax;
+        }
+        break;
+        default:
+            ARM_COMPUTE_ERROR("Not implemented");
+    }
+}
+
+template <DataLayout DL>
+void NEPriorBoxLayerKernel::calculate_prior_boxes(const Window &window)
+{
+    const int num_priors = _info.aspect_ratios().size() * _info.min_sizes().size() + _info.max_sizes().size();
+
+    const int width_idx  = get_data_layout_dimension_index(DL, DataLayoutDimension::WIDTH);
+    const int height_idx = get_data_layout_dimension_index(DL, DataLayoutDimension::HEIGHT);
+
+    const int layer_width  = _input1->info()->dimension(width_idx);
+    const int layer_height = _input1->info()->dimension(height_idx);
+
+    int img_width  = _info.img_size().x;
+    int img_height = _info.img_size().y;
+    if(img_width == 0 || img_height == 0)
+    {
+        img_width  = _input2->info()->dimension(width_idx);
+        img_height = _input2->info()->dimension(height_idx);
+    }
+
+    float step_x = _info.steps()[0];
+    float step_y = _info.steps()[1];
+    if(step_x == 0.f || step_y == 0.f)
+    {
+        step_x = static_cast<float>(img_width) / layer_width;
+        step_y = static_cast<float>(img_height) / layer_height;
+    }
+
+    Window slice = {};
+
+    switch(DL)
+    {
+        case DataLayout::NCHW:
+            slice = window.first_slice_window_2D();
+            slice.set(Window::DimY, Window::Dimension(0, _output->info()->dimension(1), 2));
+            break;
+        case DataLayout::NHWC:
+            slice = window.first_slice_window_3D();
+            slice.set(Window::DimY, Window::Dimension(0, _output->info()->dimension(1), 4 * num_priors));
+            slice.set(Window::DimZ, Window::Dimension(0, _output->info()->dimension(2), 2));
+            break;
+        default:
+            ARM_COMPUTE_ERROR("Not implemented");
+    }
+
+    Iterator output(_output, slice);
+    execute_window_loop(slice, [&](const Coordinates & id)
+    {
+        float center_x = 0;
+        float center_y = 0;
+        int   idx      = 0;
+        switch(DL)
+        {
+            case DataLayout::NCHW:
+                idx      = id.x() / (4 * num_priors);
+                center_x = (static_cast<float>(idx % layer_width) + _info.offset()) * step_x;
+                center_y = (static_cast<float>(idx / layer_width) + _info.offset()) * step_y;
+                break;
+            case DataLayout::NHWC:
+                idx      = id.y() / (4 * num_priors);
+                center_x = (static_cast<float>(idx % layer_width) + _info.offset()) * step_x;
+                center_y = (static_cast<float>(idx / layer_width) + _info.offset()) * step_y;
+                break;
+            default:
+                ARM_COMPUTE_ERROR("Not implemented");
+        }
+
+        float box_width;
+        float box_height;
+        int   offset = 0;
+
+        auto out = reinterpret_cast<float *>(output.ptr());
+        for(unsigned int i = 0; i < _info.min_sizes().size(); ++i)
+        {
+            const float min_size = _info.min_sizes().at(i);
+            box_width            = min_size;
+            box_height           = min_size;
+            store_coordinates<DL>(out, offset, center_x, center_y, box_width, box_height, img_width, img_height);
+            offset += 4;
+
+            if(!_info.max_sizes().empty())
+            {
+                const float max_size = _info.max_sizes().at(i);
+                box_width            = std::sqrt(min_size * max_size);
+                box_height           = box_width;
+
+                store_coordinates<DL>(out, offset, center_x, center_y, box_width, box_height, img_width, img_height);
+                offset += 4;
+            }
+
+            // rest of priors
+            for(auto ar : _info.aspect_ratios())
+            {
+                if(fabs(ar - 1.) < 1e-6)
+                {
+                    continue;
+                }
+
+                box_width  = min_size * sqrt(ar);
+                box_height = min_size / sqrt(ar);
+
+                store_coordinates<DL>(out, offset, center_x, center_y, box_width, box_height, img_width, img_height);
+                offset += 4;
+            }
+        }
+
+        // set the variance
+        switch(DL)
+        {
+            case DataLayout::NCHW:
+            {
+                out = reinterpret_cast<float *>(_output->ptr_to_element(Coordinates(id.x(), 1)));
+                float32x4_t var;
+                if(_info.variances().size() == 1)
+                {
+                    var = vdupq_n_f32(_info.variances().at(0));
+                }
+                else
+                {
+                    const float32x4_t vars = { _info.variances().at(0), _info.variances().at(1), _info.variances().at(2), _info.variances().at(3) };
+                    var                    = vars;
+                }
+                for(int i = 0; i < num_priors; ++i)
+                {
+                    vst1q_f32(out + 4 * i, var);
+                }
+            }
+            break;
+            case DataLayout::NHWC:
+            {
+                for(int i = 0; i < num_priors; ++i)
+                {
+                    const int  prior_offset = 4 * i;
+                    const bool single_var   = _info.variances().size() == 1;
+                    *(reinterpret_cast<float *>(_output->ptr_to_element(Coordinates(0, id.y() + prior_offset + 0, 1)))) = _info.variances().at(0);
+                    *(reinterpret_cast<float *>(_output->ptr_to_element(Coordinates(0, id.y() + prior_offset + 1, 1)))) = single_var ? _info.variances().at(0) : _info.variances().at(1);
+                    *(reinterpret_cast<float *>(_output->ptr_to_element(Coordinates(0, id.y() + prior_offset + 2, 1)))) = single_var ? _info.variances().at(0) : _info.variances().at(2);
+                    *(reinterpret_cast<float *>(_output->ptr_to_element(Coordinates(0, id.y() + prior_offset + 3, 1)))) = single_var ? _info.variances().at(0) : _info.variances().at(3);
+                }
+            }
+            break;
+            default:
+                ARM_COMPUTE_ERROR("Not implemented");
+        }
+
+    },
+    output);
+}
+
+void NEPriorBoxLayerKernel::configure(const ITensor *input1, const ITensor *input2, ITensor *output, const PriorBoxLayerInfo &info)
+{
+    ARM_COMPUTE_ERROR_ON_NULLPTR(input1, input2, output);
+
+    ARM_COMPUTE_ERROR_THROW_ON(validate_arguments(input1->info(), input2->info(), output->info(), info));
+
+    _input1 = input1;
+    _input2 = input2;
+    _info   = info;
+    _output = output;
+
+    switch(input1->info()->data_layout())
+    {
+        case DataLayout::NCHW:
+        {
+            _func = &NEPriorBoxLayerKernel::calculate_prior_boxes<DataLayout::NCHW>;
+            break;
+        }
+        case DataLayout::NHWC:
+        {
+            _func = &NEPriorBoxLayerKernel::calculate_prior_boxes<DataLayout::NHWC>;
+            break;
+        }
+        default:
+            ARM_COMPUTE_ERROR("Not implemented.");
+    }
+
+    // Configure kernel window
+    auto win_config = validate_and_configure_window(input1->info(), input2->info(), output->info(), info);
+    ARM_COMPUTE_ERROR_THROW_ON(win_config.first);
+    INEKernel::configure(win_config.second);
+}
+
+Status NEPriorBoxLayerKernel::validate(const ITensorInfo *input1, const ITensorInfo *input2, const ITensorInfo *output, const PriorBoxLayerInfo &info)
+{
+    ARM_COMPUTE_RETURN_ERROR_ON_NULLPTR(input1, input2, output);
+    ARM_COMPUTE_RETURN_ON_ERROR(validate_arguments(input1, input2, output, info));
+    ARM_COMPUTE_RETURN_ON_ERROR(validate_and_configure_window(input1->clone().get(), input2->clone().get(), output->clone().get(), info)
+                                .first);
+
+    return Status{};
+}
+void NEPriorBoxLayerKernel::run(const Window &window, const ThreadInfo &info)
+{
+    ARM_COMPUTE_UNUSED(info);
+    ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
+    ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(INEKernel::window(), window);
+    ARM_COMPUTE_ERROR_ON(_func == nullptr);
+
+    // Run function
+    (this->*_func)(window);
+}
+} // namespace arm_compute
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