Template Function thrust::set_difference(InputIterator1, InputIterator1, InputIterator2, InputIterator2, OutputIterator, StrictWeakCompare)

Function Documentation

template<typename InputIterator1, typename InputIterator2, typename OutputIterator, typename StrictWeakCompare>
OutputIterator thrust::set_difference(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, OutputIterator result, StrictWeakCompare comp)

set_difference constructs a sorted range that is the set difference of the sorted ranges [first1, last1) and [first2, last2). The return value is the end of the output range.

In the simplest case, set_difference performs the “difference” operation from set theory: the output range contains a copy of every element that is contained in [first1, last1) and not contained in [first2, last1). The general case is more complicated, because the input ranges may contain duplicate elements. The generalization is that if [first1, last1) contains m elements that are equivalent to each other and if [first2, last2) contains n elements that are equivalent to them, the last max(m-n,0) elements from [first1, last1) range shall be copied to the output range.

This version of set_difference compares elements using a function object comp.

The following code snippet demonstrates how to use

set_difference to compute the set difference of two sets of integers sorted in descending order.
Return

The end of the output range.

Pre

The ranges [first1, last1) and [first2, last2) shall be sorted with respect to comp.

Pre

The resulting range shall not overlap with either input range.

Parameters

  • first1: The beginning of the first input range.

  • last1: The end of the first input range.

  • first2: The beginning of the second input range.

  • last2: The end of the second input range.

  • result: The beginning of the output range.

  • comp: Comparison operator.

Template Parameters

  • InputIterator1: is a model of Input Iterator, InputIterator1's value_type is convertable to StrictWeakCompare's first_argument_type. and InputIterator1's value_type is convertable to a type in OutputIterator's set of value_types.

  • InputIterator2: is a model of Input Iterator, InputIterator2's value_type is convertable to StrictWeakCompare's second_argument_type. and InputIterator2's value_type is convertable to a type in OutputIterator's set of value_types.

  • OutputIterator: is a model of Output Iterator.

  • StrictWeakCompare: is a model of Strict Weak Ordering.

#include <thrust/set_operations.h>
#include <thrust/functional.h>
...
int A1[6] = {9, 6, 5, 4, 3, 1, 0};
int A2[5] = {9, 7, 5, 3, 1};

int result[3];

int *result_end = thrust::set_difference(A1, A1 + 6, A2, A2 + 5, result, thrust::greater<int>());
// result is now {6, 4, 0}

See

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

See

includes

See

set_union

See

set_intersection

See

set_symmetric_difference

See

sort

See

is_sorted