错误：下标的值不是内核中的数组，指针或向量

Question

I'm working with the following code:

__kernel                                                
void addround(__global int **A, __global int *B, int kSize, int kRound, int kNb)                                
{                   
  for (int i=0;i<kSize;i++){                            
     for (int j=0;j<kSize;j++){                     
        A[j][i]+=B[kRound*kNb*kSize+i*kNb+j];    
       }                        
   }                                                    
}

And this line A[j][i]+=B[kRound*kNb*kSize+i*kNb+j]; is marking an error, saying that it's not an array, pointer, or vector when I try to compile. I think the problem might have to do with the double pointer A, but I fail to see how. Any suggestions?

Answer 1

Double pointers do not exist in OpenCL as an input/output. Since the pointers are not allowed to travel from CPU <-> GPU.

You have to manually address matrixes, this means:

__kernel                                                
void addround(__global int *A, __global int *B, int kSize, int kRound, int kNb)                                
{                   
  for (int i=0;i<kSize;i++){                            
     for (int j=0;j<kSize;j++){                     
        A[j+i*kSize]+=B[kRound*kNb*kSize+i*kNb+j];    
       }                        
   }                                                    
}

NOTE: Just a small remark, the kernel code you are using is completely inefficient, it will take even longer than the CPU plain version. I just did the minimal changes to solve your problem, thats all.