float softplus(float x, float threshold = 20) {
    if (x > threshold) return x;                // too large
    else if (x < -threshold) return expf(x);    // too small
    return logf(expf(x) + 1);
}
float mish_activation(float input) {
    const float MISH_THRESHOLD = 20;
    output = input * tanh( softplus(input, MISH_THRESHOLD) );
    return output;
}

const float x_tmp = logistic_activate(srcData[box_index + 0]) * scale_x_y - (scale_x_y - 1) / 2;
const float y_tmp = logistic_activate(srcData[box_index + 1]) * scale_x_y - (scale_x_y - 1) / 2;
dstData[box_index + 0] = (x + x_tmp)) / cols;
dstData[box_index + 1] = (y + y_tmp)) / rows;