Thrust : how could i fill an array by range with index and range

Question

I try to fill an array by range using index and values

   thrust::device_vector<int> vec(12) 
    vec[1] = 2;
    vec[6] = 3;
    vec[10] = 1;

the result should be

vec { 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0}

instead i have

vec { 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0}

does some could tell where i'm wrong ? Thanks

Here my code :

#include <thrust/device_vector.h>
#include <thrust/scan.h>
#include <iterator>

template<class T>
struct FillRange
{
    __host__ __device__ T operator()(const T& res, const T& dat)
    {
        return dat >= T(0)  ? dat : 1;
    }
};

int main()
{
    thrust::device_vector<int> vec(12);
    vec[1] = 2;
    vec[6] = 3;
    vec[10] = 2;

    thrust::inclusive_scan(
            vec.rbegin(), vec.rend(),
            vec.rbegin(),
            FillRange<int>());

    thrust::copy(
            vec.begin(), vec.end(),
            std::ostream_iterator<int>(std::cout, " "));
    std::cout << std::endl;
}

Answer 1

Here the code for the expected result.

The array give index and the number of flag to be set: so for

   thrust::device_vector<int> vec(12) 
    vec[1] = 2;
    vec[6] = 3;
    vec[10] = 1;

the result will be

vec { 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0}

#include <thrust/device_vector.h>
#include <thrust/scan.h>
#include <iterator>


struct clean_
{
    __host__ __device__ 
    int operator()(const int &p1) const
    {
        return (p1>0)?1:p1;
    }
};

template<class T>
struct FillRange
{
    __host__ __device__ T operator()(const T& res, const T& dat)
    {
        return ((res-1)>0)? res-1 : dat ;
    }
};

int main()
{
    thrust::device_vector<int> vec(12);
    vec[1] = 2;
    vec[6]  = 3;
    vec[11] = 2;

    thrust::inclusive_scan(
            vec.begin(), vec.end(),
            vec.begin(),
            FillRange<int>());

    thrust::transform(
            vec.begin(), 
              vec.end(),
            vec.begin(),
            clean_());

    thrust::copy(
            vec.begin(), vec.end(),
            std::ostream_iterator<int>(std::cout, " "));
    std::cout << std::endl;
}