parse_split.cpp

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2015-2022 Advanced Micro Devices, Inc. All rights reserved.
 *
 * 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
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 * THE SOFTWARE.
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#include <migraphx/onnx/op_parser.hpp>
#include <migraphx/instruction.hpp>
#include <migraphx/ranges.hpp>
#include <migraphx/make_op.hpp>
#include <migraphx/tune_axis.hpp>
#include <migraphx/onnx/checks.hpp>

#include <migraphx/stringutils.hpp>

namespace migraphx {
inline namespace MIGRAPHX_INLINE_NS {
namespace onnx {

struct parse_split : op_parser<parse_split>
{
    std::vector<op_desc> operators() const { return {{"Split"}}; }

    std::vector<instruction_ref> parse(const op_desc& opd,
                                       const onnx_parser& parser,
                                       onnx_parser::node_info info,
                                       std::vector<instruction_ref> args) const
    {
        int64_t axis = 0;
        if(contains(info.attributes, "axis"))
        {
            axis = parser.parse_value(info.attributes.at("axis")).at<int>();
        }

        auto lens          = args[0]->get_shape().lens();
        int64_t n_rank     = lens.size();
        int64_t tuned_axis = tune_axis(n_rank, axis, opd.op_name);

        std::vector<int64_t> vec_splits;
        if(contains(info.attributes, "split"))
        {
            literal s = parser.parse_value(info.attributes.at("split"));
            s.visit([&](auto v) { vec_splits.assign(v.begin(), v.end()); });
        }
        else if(args.size() == 2)
        {
            auto s = args[1]->eval();
            check_arg_empty(s, "Split: dynamic shape is not supported");
            s.visit([&](auto v) { vec_splits.assign(v.begin(), v.end()); });
        }
        // no split attribute, input is equally divided
        else
        {
            std::size_t num_outputs = info.num_outputs;
            // the num_outputs attribute seems to be redundant since we already have
            // node_info::num_outputs, but we can still perform an error check
            if(contains(info.attributes, "num_outputs"))
            {
                num_outputs =
                    parser.parse_value(info.attributes.at("num_outputs")).at<std::size_t>();
                if(num_outputs != info.num_outputs)
                {
                    MIGRAPHX_THROW("PARSE_SPLIT: num_outputs attribute " +
                                   std::to_string(num_outputs) +
                                   " doesn't match actual number of outputs " +
                                   std::to_string(info.num_outputs) + "!");
                }
            }

            if(lens[tuned_axis] % num_outputs == 0)
            {
                std::size_t chunk_size = lens[tuned_axis] / num_outputs;
                vec_splits.resize(num_outputs, chunk_size);
            }
            else
            {
                std::size_t chunk_size      = lens[tuned_axis] / num_outputs + 1;
                std::size_t last_chunk_size = lens[tuned_axis] - chunk_size * (num_outputs - 1);
                vec_splits.resize(num_outputs - 1, chunk_size);
                vec_splits.push_back(last_chunk_size);
            }
        }

        if(std::accumulate(vec_splits.begin(), vec_splits.end(), int64_t(0)) !=
           static_cast<int64_t>(lens[tuned_axis]))
        {
            MIGRAPHX_THROW(
                "PARSE_SPLIT: sum of split attribute unequal to dim size of axis! tuned axis:" +
                std::to_string(lens[tuned_axis]) + " Output " + to_string_range(vec_splits) +
                " Rank " + std::to_string(n_rank) + " Len outs " + to_string_range(lens));
        }

        std::vector<instruction_ref> ret_ins;
        int64_t start = 0;
        for(auto sl : vec_splits)
        {
            ret_ins.push_back(info.add_instruction(
                make_op("slice", {{"axes", {axis}}, {"starts", {start}}, {"ends", {start + sl}}}),
                args[0]));
            start += sl;
        }

        return ret_ins;
    }
};

} // namespace onnx
} // namespace MIGRAPHX_INLINE_NS
} // namespace migraphx