void init_shifted_softmax(const pt::ptree& ptree) {
    double shift = ptree.get("global.softmax_shift", 10.0f);
    ShiftedSoftMax* ssm = (ShiftedSoftMax*) get_link_function("shifted_softmax");
    ssm->shift = shift;
    LOG(debug) << "softmax shift=" << shift;
}