ncnn/src/layer/hardsigmoid.cpp

// Tencent is pleased to support the open source community by making ncnn available.
//
// Copyright (C) 2017 THL A29 Limited, a Tencent company. All rights reserved.
//
// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// https://opensource.org/licenses/BSD-3-Clause
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#include "hardsigmoid.h"
#include <algorithm>

namespace ncnn {

DEFINE_LAYER_CREATOR(HardSigmoid)

HardSigmoid::HardSigmoid()
{
    one_blob_only = true;
    support_inplace = true;
}

int HardSigmoid::load_param(const ParamDict& pd)
{
    alpha = pd.get(0, 0.2f);
    beta = pd.get(1, 0.5f);
    lower = -beta / alpha;
    upper = (1.f / alpha) + lower;

    return 0;
}

int HardSigmoid::forward_inplace(Mat& bottom_top_blob, const Option& opt) const
{
    int w = bottom_top_blob.w;
    int h = bottom_top_blob.h;
    int channels = bottom_top_blob.c;
    int size = w * h;

    #pragma omp parallel for num_threads(opt.num_threads)
    for (int q=0; q<channels; q++)
    {
        float* ptr = bottom_top_blob.channel(q);

        for (int i=0; i<size; i++)
        {
            if (ptr[i] < lower)
                ptr[i] = 0.f;
            else if (ptr[i] > upper)
                ptr[i] = 1.f;
            else
                ptr[i] = ptr[i] * alpha + beta;
        }
    }

    return 0;
}

} // namespace ncnn