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this is my code

a definition of the zip-iterator

    `using namespace std;
    typedef thrust::device_vector<unsigned int>::iterator   IntIterator;
    typedef thrust::device_vector<float>::iterator FloatIterator;

    typedef thrust::tuple<IntIterator, FloatIterator> IteratorTuple;
    typedef thrust::zip_iterator<IteratorTuple> ZipIterator;`

a difintion of the pred 

struct is_less_than_zero_zip
   { 
      __host__ __device__
       bool operator()(ZipIterator & x)
       {
         return thrust::get<0>(x[0]) <= 5.0;
      }
   };

main function start 

int main(void)
   {
    const int N=10;

vector defintion 

    thrust::host_vector<unsigned int> h_values;
    h_values = thrust::host_vector<unsigned int>(N);
    thrust::sequence(h_values.begin(), h_values.end());
    thrust::device_vector<unsigned int> d_values;

    d_values = h_values;



    thrust::device_vector<float> d_keys;
    d_keys=h_keys;

    ZipIterator iter(thrust::make_tuple(d_values.begin(), d_keys.begin()));

the question is how to delimit my pred

is_less_than_zero_zip pred;
thrust::remove_if(iter,iter+N,pred);

return 0;
}

Thanks

wpf1118
  • 3
  • 1

1 Answers1

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I'm not sure I fully understand your question, but if I understand you correctly, you are trying to get your custom predicate to work correctly. Here are the changes you should make. (By the way, I don't know where the 5.0 comes from since you named your struct "is_less_than_zero.")

struct is_less_than_zero_zip
   { 
      __host__ __device__
       bool operator()(const thrust::tuple<int, float>& x)
       {
         return thrust::get<0>(x) <= 0; // get<0> instead of x[0]
      }
   };
Charlie H.
  • 70
  • 3
  • thanks very much,you do fully understand my question. I have the right result now. in addition how do i define my return type in this thrust::remove if – wpf1118 Apr 16 '20 at 06:25
  • I know the answer. ZipIterator new_end; new_end=thrust::remove_if(iter,iter+N,pred); int num=new_end-iter ; – wpf1118 Apr 16 '20 at 08:51