1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
/*
* Copyright 2019 Patrick Stotko
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <iostream>
#include <thrust/copy.h>
#include <thrust/reduce.h>
#include <thrust/sequence.h>
#include <stdgpu/iterator.h> // device_begin, device_end
#include <stdgpu/memory.h> // createDeviceArray, destroyDeviceArray
#include <stdgpu/platform.h> // STDGPU_HOST_DEVICE
#include <stdgpu/vector.cuh> // stdgpu::vector
struct is_odd
{
STDGPU_HOST_DEVICE bool
operator()(const int x) const
{
return x % 2 == 1;
}
};
int
main()
{
//
// EXAMPLE DESCRIPTION
// -------------------
// In this example, stdgpu::back_inserter is used to push all odd numbers of a sequence into a stdgpu::vector.
//
const stdgpu::index_t n = 100;
int* d_input = createDeviceArray<int>(n);
stdgpu::vector<int> vec = stdgpu::vector<int>::createDeviceObject(n);
thrust::sequence(stdgpu::device_begin(d_input), stdgpu::device_end(d_input), 1);
// d_input : 1, 2, 3, ..., 100
thrust::copy_if(stdgpu::device_cbegin(d_input), stdgpu::device_cend(d_input), stdgpu::back_inserter(vec), is_odd());
// vec : 1, 3, 5, ..., 99
int sum = thrust::reduce(stdgpu::device_cbegin(vec), stdgpu::device_cend(vec), 0, thrust::plus<int>());
const int sum_closed_form = n * n / 4;
std::cout << "The computed sum from i = 1 to " << n << " of i, only for odd numbers i, is " << sum << " ("
<< sum_closed_form << " expected)" << std::endl;
destroyDeviceArray<int>(d_input);
stdgpu::vector<int>::destroyDeviceObject(vec);
}
|
