thrust 学习笔记

gather与scatter正好相反：

scatter是顺序输入根据map确定撒点输出位置。

  

   

    

     

    
    

     

      #include <thrust/scatter.h>
     
    
   

    

     

    
    

     

      #include <thrust/device_vector.h>
     
    
   

    

     

    
    

     

      #include <thrust/execution_policy.h>
     
    
   

    

     

    
    

     

      ...
     
    
   

    

     

    
    

     

      // mark even indices with a 1; odd indices with a 0
     
    
   

    

     

    
    

     

      int values[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
     
    
   

    

     

    
    

     

      thrust::device_vector<int> d_values(values, values + 10);
     
    
   

    

     

    
    

     

      // scatter all even indices into the first half of the
     
    
   

    

     

    
    

     

      // range, and odd indices vice versa
     
    
   

    

     

    
    

     

      int map[10]   = {0, 5, 1, 6, 2, 7, 3, 8, 4, 9};
     
    
   

    

     

    
    

     

      thrust::device_vector<int> d_map(map, map + 10);
     
    
   

    

     

    
    

     

      thrust::device_vector<int> d_output(10);
     
    
   

    

     

    
    

     

      thrust::scatter(thrust::device,
     
    
   

    

     

    
    

     

                      d_values.begin(), d_values.end(),
     
    
   

    

     

    
    

     

                      d_map.begin(), d_output.begin());
     
    
   

    

     

    
    

     

      // d_output is now {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
     
    
  
 

gather是根据map确定输入元素的位置，输出是按顺序的。

  

   

    

     

    
    

     

      #include <thrust/gather.h>
     
    
   

    

     

    
    

     

      #include <thrust/device_vector.h>
     
    
   

    

     

    
    

     

      #include <thrust/execution_policy.h>
     
    
   

    

     

    
    

     

      ...
     
    
   

    

     

    
    

     

      // mark even indices with a 1; odd indices with a 0
     
    
   

    

     

    
    

     

      int values[10] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
     
    
   

    

     

    
    

     

      thrust::device_vector<int> d_values(values, values + 10);
     
    
   

    

     

    
    

     

      // gather all even indices into the first half of the range
     
    
   

    

     

    
    

     

      // and odd indices to the last half of the range
     
    
   

    

     

    
    

     

      int map[10]   = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
     
    
   

    

     

    
    

     

      thrust::device_vector<int> d_map(map, map + 10);
     
    
   

    

     

    
    

     

      thrust::device_vector<int> d_output(10);
     
    
   

    

     

    
    

     

      thrust::gather(thrust::device,
     
    
   

    

     

    
    

     

                     d_map.begin(), d_map.end(),
     
    
   

    

     

    
    

     

                     d_values.begin(),
     
    
   

    

     

    
    

     

                     d_output.begin());
     
    
   

    

     

    
    

     

      // d_output is now {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
     
    
  
 

如图：

具体可以查看 https://blog.csdn.net/seamanj/article/details/82976687
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原文链接：https://blog.csdn.net/shungry/article/details/103079320

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原文链接：blog.csdn.net/jacke121/article/details/123785472