MegEngine/src/opr/impl/dnn/helper.h

/**
 * \file src/opr/impl/dnn/helper.h
 * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
 *
 * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 */

#pragma once

#include "megbrain/graph.h"

namespace mgb {
namespace opr {
namespace intl {

//! grad for conv like oprs: Fwd should take (src, filter) as its param
template <class BwdData, class BwdFilter, class Fwd>
VarNode* conv_grad(Fwd& opr, size_t wrt_idx, const VarNodeArray& out_grad) {
    mgb_assert(wrt_idx == 0 || wrt_idx == 1);
    mgb_assert(out_grad.size() == 2);
    if (wrt_idx == 0) {
        // data
        SymbolVar grad =
                BwdData::make(opr.input(1), out_grad[0], opr.input(0), opr.param());
        return grad.node();
    } else {
        // filter
        SymbolVar grad =
                BwdFilter::make(opr.input(0), out_grad[0], opr.input(1), opr.param());
        return grad.node();
    }
}

}  // namespace intl
}  // namespace opr
}  // namespace mgb

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