tdigest_column_view.hpp

/*
 * Copyright (c) 2021-2023, NVIDIA CORPORATION.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#pragma once
 
#include <cudf/column/column_view.hpp>
#include <cudf/lists/lists_column_view.hpp>
 
namespace cudf {
namespace tdigest {
 
class tdigest_column_view : private column_view {
 public:
  tdigest_column_view(column_view const&);  
  tdigest_column_view(tdigest_column_view&&)      = default;  
  tdigest_column_view(tdigest_column_view const&) = default;  
  ~tdigest_column_view()                          = default;
  tdigest_column_view& operator=(tdigest_column_view const&) = default;
  tdigest_column_view& operator=(tdigest_column_view&&) = default;
 
  using column_view::size;
  static_assert(std::is_same_v<offset_type, size_type>,
                "offset_type is expected to be the same as size_type.");
  using offset_iterator = offset_type const*;  
 
  // mean and weight column indices within tdigest inner struct columns
  static constexpr size_type mean_column_index{0};    
  static constexpr size_type weight_column_index{1};  
 
  // min and max column indices within tdigest outer struct columns
  static constexpr size_type centroid_column_index{0};  
  static constexpr size_type min_column_index{1};       
  static constexpr size_type max_column_index{2};       
 
  [[nodiscard]] column_view parent() const;
 
  [[nodiscard]] lists_column_view centroids() const;
 
  [[nodiscard]] column_view means() const;
 
  [[nodiscard]] column_view weights() const;
 
  [[nodiscard]] double const* min_begin() const;
 
  [[nodiscard]] double const* max_begin() const;
};
 
}  // namespace tdigest
}  // namespace cudf