[Solved] Cuda: Compact and result size

by


You can do this using thrust as @RobertCrovella already pointed out.
The following example uses thrust::copy_if to copy all of elements’ indices for which the condition (“equals 7”) is fulfilled. thrust::counting_iterator is used to avoid creating the sequence of indices explicitly.

#include <thrust/copy.h>
#include <thrust/iterator/counting_iterator.h>
#include <thrust/functional.h>
#include <iostream>

using namespace thrust::placeholders;

int main()
{
    const int N = 10;
    int objectArray[N] = { 1, 11, 7, 2, 7, 23, 6, 6, 9, 11 };
    int results[N]={0};

    int* end = thrust::copy_if(thrust::make_counting_iterator(0), thrust::make_counting_iterator(N), objectArray, results, _1 == 7);

    thrust::copy(results, results+N, std::ostream_iterator<int>(std::cout, " "));
    std::cout << std::endl << "result count = " << end-results << std::endl;
    return 0;
}

Output:

2 4 0 0 0 0 0 0 0 0
result count = 2

3

solved Cuda: Compact and result size