Method SetDefault

include/dmlc/parameter.h:654–663

implement set head to default value

  }
  // implement set head to default value
  void SetDefault(void *head) const override {
    if (!has_default_) {
      std::ostringstream os;
      os << "Required parameter " << key_
         << " of " << type_ << " is not presented";
      throw dmlc::ParamError(os.str());
    } else {
      this->Get(head) = default_value_;
    }
  }
  // return reference of self as derived type
  inline TEntry &self() {
    return *(static_cast<TEntry*>(this));