Template Function thrust::uninitialized_copy_n(InputIterator, Size, ForwardIterator)

Function Documentation

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.
Return

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.

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.

#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

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

See

uninitialized_copy

See

copy

See

uninitialized_fill

See

device_new

See

device_malloc