使用CUDA在矩阵中添加相邻元素

给定一个nxn矩阵，我想找到相邻元素（上、下、左、右）的总和，并使用CUDA将中间元素替换为该总和，即，所有操作都应该并行完成

例如，使用3个元素

1 2 3

4 5 6

7 8 9

如果我们取中间元素（坐标（1,1）），相邻元素之和为（2+4+6+8=）20。这应该用中间元素替换

1 2 3

4206

7 8 9

这是我写的代码。如果n=3，此代码将起作用，如果n更大（例如：n=5），此代码将不起作用。请给我一个方法来概括这段代码

请帮帮我

#include <stdio.h>
#include <stdlib.h>

#define N 3
#define BLOCK_DIM 3

__global__ void matrixAdd (int *a, int *c) {
    int col = blockIdx.x * blockDim.x + threadIdx.x;
    int row = blockIdx.y * blockDim.y + threadIdx.y;

    int index = col + row * N;

    int sum = 0;
    if (row == 1 && col == 1 && col < N && row < N) {
        sum = sum + a[index - 1];
        sum = sum + a[index + 1];
        sum = sum + a[index - 3];
        sum = sum + a[index + 3];
    }
    c[index] = sum;
}

void printMatrix(int a[N][N] )
{
    for(int i=0; i<N; i++){
        for (int j=0; j<N; j++){
            printf("%d\t", a[i][j] );
        }
        printf("\n");
    }
}

int main() {
    int a[N][N], c[N][N];
    int *dev_a, *dev_c;

    int size = N * N * sizeof(int);

    for(int i=0; i<N; i++)
        for (int j=0; j<N; j++){
            a[i][j] = rand() % 256;
        }

    printf("Matrix A\n");
    printMatrix(a);

    cudaMalloc((void**)&dev_a, size);
    cudaMalloc((void**)&dev_c, size);

    cudaMemcpy(dev_a, a, size, cudaMemcpyHostToDevice);

    dim3 dimBlock(BLOCK_DIM, BLOCK_DIM);
    dim3 dimGrid((N+dimBlock.x-1)/dimBlock.x, (N+dimBlock.y-1)/dimBlock.y);

    printf("dimGrid.x = %d, dimGrid.y = %d\n", dimGrid.x, dimGrid.y);

    matrixAdd<<<dimGrid,dimBlock>>>(dev_a,dev_c);
    cudaDeviceSynchronize();
    cudaMemcpy(c, dev_c, size, cudaMemcpyDeviceToHost);

    printf("Matrix c\n");
    printMatrix(c);

    cudaFree(dev_a);
    cudaFree(dev_c);
}

#包括
#包括
#定义n3
#定义块_DIM 3
__全局无效矩阵ADD（int*a，int*c）{
int col=blockIdx.x*blockDim.x+threadIdx.x；
int row=blockIdx.y*blockDim.y+threadIdx.y；
int index=列+行*N；
整数和=0；
如果（行==1&&col==1&&col对于（int i=0；i如果您希望每个输出元素都是其输入的上、下、左、右邻域的总和，则只需在代码中做一点小更改即可处理任意大小的元素，如下所示：

if (row == 1 && col == 1 && col < N && row < N) {
    sum = sum + a[index - 1];
    sum = sum + a[index + 1];
    sum = sum + a[index - 3];
    sum = sum + a[index + 3];
}
c[index] = sum;

if (row > 0 && col > 0 && col < N-1 && row < N-1 ) {  //note the change
    sum = sum + a[index - 1];
    sum = sum + a[index + 1];
    sum = sum + a[index - N];                         //note the change
    sum = sum + a[index + N];                         //note the change
    c[index] = sum;                                   //note the change
}

cudaMemcpy(dev_c, a, size, cudaMemcpyHostToDevice);