thrust

◆ stable_partition_copy() [4/4]

template<typename InputIterator1 , typename InputIterator2 , typename OutputIterator1 , typename OutputIterator2 , typename Predicate >
thrust::pair<OutputIterator1,OutputIterator2> thrust::stable_partition_copy ( InputIterator1  first,
InputIterator1  last,
InputIterator2  stencil,
OutputIterator1  out_true,
OutputIterator2  out_false,
Predicate  pred 
)

stable_partition_copy differs from stable_partition only in that the reordered sequence is written to different output sequences, rather than in place.

stable_partition_copy copies the elements [first, last) based on the function object pred which is applied to a range of stencil elements. All of the elements whose corresponding stencil element satisfies pred are copied to the range beginning at out_true and all the elements whose stencil element fails to satisfy it are copied to the range beginning at out_false.

stable_partition_copy differs from partition_copy in that stable_partition_copy is guaranteed to preserve relative order. That is, if x and y are elements in [first, last), such that pred(x) == pred(y), and if x precedes y, then it will still be true after stable_partition_copy that x precedes y in the output.

Parameters
firstThe first element of the sequence to reorder.
lastOne position past the last element of the sequence to reorder.
stencilThe beginning of the stencil sequence.
out_trueThe destination of the resulting sequence of elements which satisfy pred.
out_falseThe destination of the resulting sequence of elements which fail to satisfy pred.
predA function object which decides to which partition each element of the sequence [first, last) belongs.
Returns
A pair p such that p.first is the end of the output range beginning at out_true and p.second is the end of the output range beginning at out_false.
Template Parameters
InputIterator1is a model of Input Iterator, and InputIterator's value_type is convertible to OutputIterator1 and OutputIterator2's value_types.
InputIterator2is a model of Input Iterator, and InputIterator2's value_type is convertible to Predicate's argument_type.
OutputIterator1is a model of Output Iterator.
OutputIterator2is a model of Output Iterator.
Predicateis a model of Predicate.
Precondition
The input ranges shall not overlap with either output range.

The following code snippet demonstrates how to use stable_partition_copy to reorder a sequence so that even numbers precede odd numbers.

...
int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
int S[] = {0, 1, 0, 1, 0, 1, 0, 1, 0, 1};
int result[10];
const int N = sizeof(A)/sizeof(int);
int *evens = result;
int *odds = result + 5;
// A remains {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
// S remains {0, 1, 0, 1, 0, 1, 0, 1, 0, 1}
// result is now {2, 4, 6, 8, 10, 1, 3, 5, 7, 9}
// evens points to {2, 4, 6, 8, 10}
// odds points to {1, 3, 5, 7, 9}
See also
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2569.pdf
partition_copy
stable_partition