Function MaxSummaryQueryRankError

tests/cpp/common/test_quantile.h:510–521

template <typename Summary>
double MaxSummaryQueryRankError(Summary const& summary, ReferenceColumn const& reference,
                                std::size_t num_queries) {
  auto total = TotalWeight(reference);
  CHECK_GT(total, 0.0);
  double max_error = 0.0;
  for (std::size_t i = 1; i < num_queries; ++i) {
    auto target = static_cast<double>(i) * total / static_cast<double>(num_queries);
    auto queried = QuerySummaryValue(summary, target);
    max_error = std::max(max_error, RankErrorForValue(reference, target, queried));
  }
  return max_error;
}
}  // namespace xgboost::common::quantile_test

#endif  // TESTS_CPP_COMMON_TEST_QUANTILE_H_