Method add_callback

src/models/model.cpp:547–556

}

void model::add_callback(std::shared_ptr<callback_base> cb)
{
  if (cb == nullptr) {
    LBANN_ERROR("attempted to add a null pointer as callback to ",
                "model \"",
                get_name(),
                "\"");
  }
  m_callbacks.emplace_back(std::move(cb));
}

void model::add_metric(std::unique_ptr<metric> m)
{