thrust::stable_partition_copy

Defined in thrust/partition.h

template<typename DerivedPolicy, typename InputIterator1, typename InputIterator2, typename OutputIterator1, typename OutputIterator2, typename Predicate> thrust::pair<OutputIterator1, OutputIterator2> thrust::stable_partition_copy(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, 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.

The algorithm’s execution is parallelized as determined by exec.

The following code snippet demonstrates how to use stable_partition_copy to reorder a sequence so that even numbers precede odd numbers using the thrust::host execution policy for parallelization:

#include <thrust/partition.h>
#include <thrust/functional.h>
#include <thrust/execution_policy.h>
...
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;
thrust::stable_partition_copy(thrust::host, A, A + N, S, evens, odds, thrust::identity<int>());
// 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}