thrust::is_partitioned

Defined in thrust/partition.h

template<typename DerivedPolicy, typename InputIterator, typename Predicate> bool thrust::is_partitioned(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, InputIterator first, InputIterator last, Predicate pred)

is_partitioned returns true if the given range is partitioned with respect to a predicate, and false otherwise.

Specifically, is_partitioned returns true if [first, last) is empty of if [first, last) is partitioned by pred, i.e. if all elements that satisfy pred appear before those that do not.

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

#include <thrust/partition.h>
#include <thrust/execution_policy.h>

struct is_even
{
  __host__ __device__
  bool operator()(const int &x)
  {
    return (x % 2) == 0;
  }
};

...

int A[] = {2, 4, 6, 8, 10, 1, 3, 5, 7, 9};
int B[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

thrust::is_partitioned(thrust::host, A, A + 10, is_even()); // returns true
thrust::is_partitioned(thrust::host, B, B + 10, is_even()); // returns false