mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 05:32:52 +00:00
57 lines
1.4 KiB
C++
57 lines
1.4 KiB
C++
#pragma once
|
||
|
||
#include <vector>
|
||
|
||
#include <DB/Core/Field.h>
|
||
#include <DB/Core/FieldVisitors.h>
|
||
|
||
|
||
namespace DB
|
||
{
|
||
|
||
namespace ErrorCodes
|
||
{
|
||
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
|
||
}
|
||
|
||
/** Параметры разных функций quantilesSomething.
|
||
* - список уровней квантилей.
|
||
* Также необходимо вычислить массив индексов уровней, идущих по возрастанию.
|
||
*
|
||
* Пример: quantiles(0.5, 0.99, 0.95)(x).
|
||
* levels: 0.5, 0.99, 0.95
|
||
* levels_permutation: 0, 2, 1
|
||
*/
|
||
template <typename T> /// float или double
|
||
struct QuantileLevels
|
||
{
|
||
using Levels = std::vector<T>;
|
||
using Permutation = std::vector<size_t>;
|
||
|
||
Levels levels;
|
||
Permutation permutation; /// Индекс i-го по величине уровня в массиве levels.
|
||
|
||
size_t size() const { return levels.size(); }
|
||
|
||
void set(const Array & params)
|
||
{
|
||
if (params.empty())
|
||
throw Exception("Aggregate function quantiles requires at least one parameter.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
|
||
|
||
size_t size = params.size();
|
||
levels.resize(size);
|
||
permutation.resize(size);
|
||
|
||
for (size_t i = 0; i < size; ++i)
|
||
{
|
||
levels[i] = applyVisitor(FieldVisitorConvertToNumber<Float64>(), params[i]);
|
||
permutation[i] = i;
|
||
}
|
||
|
||
std::sort(permutation.begin(), permutation.end(), [this] (size_t a, size_t b) { return levels[a] < levels[b]; });
|
||
}
|
||
};
|
||
|
||
|
||
}
|