src/graph/nodes/BranchLayer.cpp

/*
 * Copyright (c) 2017-2018 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/graph/nodes/BranchLayer.h"

#include "arm_compute/graph/Error.h"
#include "arm_compute/graph/Graph.h"
#include "arm_compute/graph/SubGraph.h"
#include "arm_compute/graph/Tensor.h"
#include "arm_compute/runtime/IFunction.h"
#include "support/ToolchainSupport.h"
#include "utils/TypePrinter.h"

#include <memory>
#include <tuple>
#include <vector>

using namespace arm_compute::graph;

/** Branch function */
class BranchFunction final : public arm_compute::IFunction
{
public:
    /** Default Constructor */
    BranchFunction()
        : _graphs()
    {
    }
    /** Registers graph to be executed by the branch function
     *
     * @param[in] graph Graph to register
     */
    void register_graph(std::unique_ptr<Graph> graph)
    {
        _graphs.push_back(std::move(graph));
    }
    // Inherited methods overriden:
    void run() override
    {
        for(auto &g : _graphs)
        {
            ARM_COMPUTE_ERROR_ON(g.get() == nullptr);
            g->run();
        }
    }

private:
    std::vector<std::unique_ptr<Graph>> _graphs;
};

std::unique_ptr<arm_compute::IFunction> BranchLayer::instantiate_node(GraphContext &ctx, ITensorObject *input, ITensorObject *output)
{
    ARM_COMPUTE_ERROR_ON(_branch_merge_method != BranchMergeMethod::DEPTH_CONCATENATE);
    ARM_COMPUTE_UNUSED(_branch_merge_method);
    ARM_COMPUTE_ERROR_ON_UNALLOCATED_TENSOR_OBJECT(input, output);

    // Create branch function
    auto func = arm_compute::support::cpp14::make_unique<BranchFunction>();

    // Track output depth
    int depth = 0;

    // Constuct all sub-graphs given the input/output
    for(auto &sg : _sub_graphs)
    {
        ARM_COMPUTE_ERROR_ON(sg.get() == nullptr);

        // IO buffers
        std::unique_ptr<ITensorObject> in;
        std::unique_ptr<ITensorObject> out;
        SubTensor                     *out_sub_tensor = nullptr;

        // Create input sub-tensor
        if(!sg->has_input())
        {
            ARM_COMPUTE_ERROR_ON(dynamic_cast<Tensor *>(input) == nullptr);
            in = arm_compute::support::cpp14::make_unique<SubTensor>(*dynamic_cast<Tensor *>(input),
                                                                     input->tensor()->info()->tensor_shape(),
                                                                     Coordinates());
        }

        // Create output sub-tensor
        if(!sg->has_output())
        {
            ARM_COMPUTE_ERROR_ON((dynamic_cast<Tensor *>(output) == nullptr) && (dynamic_cast<SubTensor *>(output) == nullptr));

            out = arm_compute::support::cpp14::make_unique<SubTensor>(output->tensor(),
                                                                      TensorShape(),
                                                                      Coordinates(0, 0, depth),
                                                                      output->target(),
                                                                      true);
            out_sub_tensor = dynamic_cast<SubTensor *>(out.get());
        }

        // Construct sub_graph
        auto g = sg->construct(ctx, std::move(in), std::move(out));

        // Register graph to function
        func->register_graph(std::move(g));

        // Update and track depth
        if(out_sub_tensor != nullptr)
        {
            ARM_COMPUTE_ERROR_ON(out_sub_tensor->tensor() == nullptr);
            depth += out_sub_tensor->tensor()->info()->tensor_shape()[2];
        }
    }

    return std::move(func);
}