Method LoadConfig

src/learner.cc:569–622

  }

  void LoadConfig(Json const& in) override {
    // If configuration is loaded, ensure that the model came from the same version
    CHECK(IsA<Object>(in));
    auto origin_version = Version::Load(in);
    if (std::get<0>(Version::kInvalid) == std::get<0>(origin_version)) {
      LOG(WARNING) << "Invalid version string in config";
    }

    if (!Version::Same(origin_version)) {
      error::WarnOldSerialization();
      return;  // skip configuration if version is not matched
    }

    auto const& learner_parameters = get<Object>(in["learner"]);
    FromJson(learner_parameters.at("learner_train_param"), &tparam_);

    auto const& gradient_booster = learner_parameters.at("gradient_booster");

    auto const& objective_fn = learner_parameters.at("objective");
    if (!obj_) {
      CHECK_EQ(get<String const>(objective_fn["name"]), tparam_.objective);
      obj_.reset(ObjFunction::Create(tparam_.objective, &ctx_));
    }
    obj_->LoadConfig(objective_fn);
    learner_model_param_.task = obj_->Task();

    tparam_.booster = CanonicalizeBoosterName(get<String>(gradient_booster["name"]));
    if (!gbm_) {
      gbm_.reset(GradientBooster::Create(tparam_.booster, &ctx_, &learner_model_param_));
    }
    gbm_->LoadConfig(gradient_booster);

    auto const& j_metrics = learner_parameters.at("metrics");
    auto n_metrics = get<Array const>(j_metrics).size();
    metric_names_.resize(n_metrics);
    metrics_.resize(n_metrics);
    for (size_t i = 0; i < n_metrics; ++i) {
      auto old_serialization = IsA<String>(j_metrics[i]);
      if (old_serialization) {
        error::WarnOldSerialization();
        metric_names_[i] = get<String>(j_metrics[i]);
      } else {
        metric_names_[i] = get<String>(j_metrics[i]["name"]);
      }
      metrics_[i] = std::unique_ptr<Metric>(Metric::Create(metric_names_[i], &ctx_));
      if (!old_serialization) {
        metrics_[i]->LoadConfig(j_metrics[i]);
      }
    }

    ctx_.FromJson(learner_parameters.at("generic_param"));

    this->need_configuration_ = true;
  }

  void SaveConfig(Json* p_out) const override {
    CHECK(!this->need_configuration_) << "Call Configure before saving model.";