Method FieldEntryNumeric

include/dmlc/parameter.h:714–715

    : public FieldEntryBase<TEntry, DType> {
 public:
  FieldEntryNumeric()
      : has_begin_(false), has_end_(false) {}
  // implement set_range
  virtual TEntry &set_range(DType begin, DType end) {
    begin_ = begin; end_ = end;