|
|
#ifndef SCIQLOP_SORTUTILS_H
|
|
|
#define SCIQLOP_SORTUTILS_H
|
|
|
|
|
|
#include <algorithm>
|
|
|
#include <cmath>
|
|
|
#include <numeric>
|
|
|
#include <vector>
|
|
|
|
|
|
/**
|
|
|
* Utility class with methods for sorting data
|
|
|
*/
|
|
|
struct SortUtils {
|
|
|
/**
|
|
|
* Generates a vector representing the index of insertion of each data of a container if this
|
|
|
* one had to be sorted according to a comparison function.
|
|
|
*
|
|
|
* For example:
|
|
|
* If the container is a vector {1; 4; 2; 5; 3} and the comparison function is std::less, the
|
|
|
* result would be : {0; 3; 1; 4; 2}
|
|
|
*
|
|
|
* @tparam Container the type of the container.
|
|
|
* @tparam Compare the type of the comparison function
|
|
|
* @param container the container from which to generate the result. The container must have a
|
|
|
* at() method that returns a value associated to an index
|
|
|
* @param compare the comparison function
|
|
|
*/
|
|
|
template <typename Container, typename Compare>
|
|
|
static std::vector<int> sortPermutation(const Container &container, const Compare &compare)
|
|
|
{
|
|
|
auto permutation = std::vector<int>{};
|
|
|
permutation.resize(container.size());
|
|
|
|
|
|
std::iota(permutation.begin(), permutation.end(), 0);
|
|
|
std::sort(permutation.begin(), permutation.end(),
|
|
|
[&](int i, int j) { return compare(container.at(i), container.at(j)); });
|
|
|
return permutation;
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* Sorts a container according to indices passed in parameter
|
|
|
* @param container the container sorted
|
|
|
* @param sortPermutation the indices used to sort the container
|
|
|
* @return the container sorted
|
|
|
* @warning no verification is made on validity of sortPermutation (i.e. the vector has unique
|
|
|
* indices and its range is [0 ; vector.size()[ )
|
|
|
*/
|
|
|
template <typename Container>
|
|
|
static Container sort(const Container &container, const std::vector<int> &sortPermutation)
|
|
|
{
|
|
|
if (container.size() != sortPermutation.size()) {
|
|
|
return Container{};
|
|
|
}
|
|
|
|
|
|
// Inits result
|
|
|
auto sortedData = Container{};
|
|
|
sortedData.resize(container.size());
|
|
|
|
|
|
std::transform(sortPermutation.cbegin(), sortPermutation.cend(), sortedData.begin(),
|
|
|
[&container](int i) { return container.at(i); });
|
|
|
|
|
|
return sortedData;
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* Compares two values that can be NaN. This method is intended to be used as a compare function
|
|
|
* for searching min value by excluding NaN values.
|
|
|
*
|
|
|
* Examples of use:
|
|
|
* - f({1, 3, 2, 4, 5}) will return 1
|
|
|
* - f({NaN, 3, 2, 4, 5}) will return 2 (NaN is excluded)
|
|
|
* - f({NaN, NaN, 3, NaN, NaN}) will return 3 (NaN are excluded)
|
|
|
* - f({NaN, NaN, NaN, NaN, NaN}) will return NaN (no existing value)
|
|
|
*
|
|
|
* @param v1 first value
|
|
|
* @param v2 second value
|
|
|
* @return true if v1 < v2, false otherwise
|
|
|
* @sa std::min_element
|
|
|
*/
|
|
|
template <typename T>
|
|
|
static bool minCompareWithNaN(const T &v1, const T &v2)
|
|
|
{
|
|
|
// Table used with NaN values:
|
|
|
// NaN < v2 -> false
|
|
|
// v1 < NaN -> true
|
|
|
// NaN < NaN -> false
|
|
|
// v1 < v2 -> v1 < v2
|
|
|
return std::isnan(v1) ? false : std::isnan(v2) || (v1 < v2);
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* Compares two values that can be NaN. This method is intended to be used as a compare function
|
|
|
* for searching max value by excluding NaN values.
|
|
|
*
|
|
|
* Examples of use:
|
|
|
* - f({1, 3, 2, 4, 5}) will return 5
|
|
|
* - f({1, 3, 2, 4, NaN}) will return 4 (NaN is excluded)
|
|
|
* - f({NaN, NaN, 3, NaN, NaN}) will return 3 (NaN are excluded)
|
|
|
* - f({NaN, NaN, NaN, NaN, NaN}) will return NaN (no existing value)
|
|
|
*
|
|
|
* @param v1 first value
|
|
|
* @param v2 second value
|
|
|
* @return true if v1 < v2, false otherwise
|
|
|
* @sa std::max_element
|
|
|
*/
|
|
|
template <typename T>
|
|
|
static bool maxCompareWithNaN(const T &v1, const T &v2)
|
|
|
{
|
|
|
// Table used with NaN values:
|
|
|
// NaN < v2 -> true
|
|
|
// v1 < NaN -> false
|
|
|
// NaN < NaN -> false
|
|
|
// v1 < v2 -> v1 < v2
|
|
|
return std::isnan(v1) ? true : !std::isnan(v2) && (v1 < v2);
|
|
|
}
|
|
|
};
|
|
|
|
|
|
#endif // SCIQLOP_SORTUTILS_H
|
|
|
|
