Template Function thrust::stable_sort_by_key(RandomAccessIterator1, RandomAccessIterator1, RandomAccessIterator2)

Function Documentation

template<typename RandomAccessIterator1, typename RandomAccessIterator2>
void thrust::stable_sort_by_key(RandomAccessIterator1 keys_first, RandomAccessIterator1 keys_last, RandomAccessIterator2 values_first)

stable_sort_by_key performs a key-value sort. That is, stable_sort_by_key sorts the elements in [keys_first, keys_last) and [values_first, values_first + (keys_last - keys_first)) into ascending key order, meaning that if i and j are any two valid iterators in [keys_first, keys_last) such that i precedes j, and p and q are iterators in [values_first, values_first + (keys_last - keys_first)) corresponding to i and j respectively, then *j is not less than *i.

As the name suggests, stable_sort_by_key is stable: it preserves the relative ordering of equivalent elements. That is, if x and y are elements in [keys_first, keys_last) such that x precedes y, and if the two elements are equivalent (neither x < y nor y < x) then a postcondition of stable_sort_by_key is that x still precedes y.

This version of stable_sort_by_key compares key objects using operator<.

The following code snippet demonstrates how to use

stable_sort_by_key to sort an array of characters using integers as sorting keys.
Pre

The range [keys_first, keys_last)) shall not overlap the range [values_first, values_first + (keys_last - keys_first)).

Parameters

  • keys_first: The beginning of the key sequence.

  • keys_last: The end of the key sequence.

  • values_first: The beginning of the value sequence.

Template Parameters

  • RandomAccessIterator1: is a model of Random Access Iterator, RandomAccessIterator1 is mutable, and RandomAccessIterator1's value_type is a model of LessThan Comparable, and the ordering relation on RandomAccessIterator1's value_type is a strict weak ordering, as defined in the LessThan Comparable requirements.

  • RandomAccessIterator2: is a model of Random Access Iterator, and RandomAccessIterator2 is mutable.

#include <thrust/sort.h>
...
const int N = 6;
int    keys[N] = {  1,   4,   2,   8,   5,   7};
char values[N] = {'a', 'b', 'c', 'd', 'e', 'f'};
thrust::stable_sort_by_key(keys, keys + N, values);
// keys is now   {  1,   2,   4,   5,   7,   8}
// values is now {'a', 'c', 'b', 'e', 'f', 'd'}

See

http://www.sgi.com/tech/stl/sort.html

See

sort_by_key

See

stable_sort