thrust::uninitialized_copy_n#

Overloads#

uninitialized_copy_n(exec, first, n, result)#

template<typename DerivedPolicy, typename InputIterator, typename Size, typename ForwardIterator>
ForwardIterator thrust::uninitialized_copy_n(
const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
InputIterator first,
Size n,
ForwardIterator result,
)#

In thrust, the function thrust::device_new allocates memory for an object and then creates an object at that location by calling a constructor. Occasionally, however, it is useful to separate those two operations. If each iterator in the range [result, result + n) points to uninitialized memory, then uninitialized_copy_n creates a copy of [first, first + n) in that range. That is, for each iterator i in the input, uninitialized_copy_n creates a copy of *i in the location pointed to by the corresponding iterator in the output range by InputIterator's value_type's copy constructor with *i as its argument.

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

The following code snippet demonstrates how to use uninitialized_copy to initialize a range of uninitialized memory using the thrust::device execution policy for parallelization:

#include <thrust/uninitialized_copy.h>
#include <thrust/device_malloc.h>
#include <thrust/device_vector.h>
#include <thrust/execution_policy.h>

struct Int
{
  __host__ __device__
  Int(int x) : val(x) {}
  int val;
};
...
const int N = 137;

Int val(46);
thrust::device_vector<Int> input(N, val);
thrust::device_ptr<Int> array = thrust::device_malloc<Int>(N);
thrust::uninitialized_copy_n(thrust::device, input.begin(), N, array);

// Int x = array[i];
// x.val == 46 for all 0 <= i < N

See also

https://en.cppreference.com/w/cpp/memory/uninitialized_copy

See also

uninitialized_copy

See also

copy

See also

uninitialized_fill

See also

device_new

See also

device_malloc

Parameters:

  • exec – The execution policy to use for parallelization.

  • first – The first element of the input range to copy from.

  • n – The number of elements to copy.

  • result – The first element of the output range to copy to.

Template Parameters:

  • DerivedPolicy – The name of the derived execution policy.

  • InputIterator – is a model of Input Iterator.

  • Size – is an integral type.

  • ForwardIterator – is a model of Forward Iterator, ForwardIterator is mutable, and ForwardIterator's value_type has a constructor that takes a single argument whose type is InputIterator's value_type.

Returns:

An iterator pointing to the last element of the output range.

Pre:

first may equal result, but the range [first, first + n) and the range [result, result + n) shall not overlap otherwise.

uninitialized_copy_n(first, n, result)#

template<typename InputIterator, typename Size, typename ForwardIterator>
ForwardIterator thrust::uninitialized_copy_n(
InputIterator first,
Size n,
ForwardIterator result,
)#

In thrust, the function thrust::device_new allocates memory for an object and then creates an object at that location by calling a constructor. Occasionally, however, it is useful to separate those two operations. If each iterator in the range [result, result + n) points to uninitialized memory, then uninitialized_copy_n creates a copy of [first, first + n) in that range. That is, for each iterator i in the input, uninitialized_copy_n creates a copy of *i in the location pointed to by the corresponding iterator in the output range by InputIterator's value_type's copy constructor with *i as its argument.

The following code snippet demonstrates how to use uninitialized_copy to initialize a range of uninitialized memory.

#include <thrust/uninitialized_copy.h>
#include <thrust/device_malloc.h>
#include <thrust/device_vector.h>

struct Int
{
  __host__ __device__
  Int(int x) : val(x) {}
  int val;
};
...
const int N = 137;

Int val(46);
thrust::device_vector<Int> input(N, val);
thrust::device_ptr<Int> array = thrust::device_malloc<Int>(N);
thrust::uninitialized_copy_n(input.begin(), N, array);

// Int x = array[i];
// x.val == 46 for all 0 <= i < N

See also

https://en.cppreference.com/w/cpp/memory/uninitialized_copy

See also

uninitialized_copy

See also

copy

See also

uninitialized_fill

See also

device_new

See also

device_malloc

Parameters:

  • first – The first element of the input range to copy from.

  • n – The number of elements to copy.

  • result – The first element of the output range to copy to.

Template Parameters:

  • InputIterator – is a model of Input Iterator.

  • Size – is an integral type.

  • ForwardIterator – is a model of Forward Iterator, ForwardIterator is mutable, and ForwardIterator's value_type has a constructor that takes a single argument whose type is InputIterator's value_type.

Returns:

An iterator pointing to the last element of the output range.

Pre:

first may equal result, but the range [first, first + n) and the range [result, result + n) shall not overlap otherwise.