连续CUDA内核启动后丢失数据

Question

我正在尝试创建一个双元素数组，其中每个元素都是元素的总和。但是，添加新值后，该值将丢失，并且向量vet再次用零填充，好像什么也没发生。

我尝试使用共享向量无济于事。还尝试同步该过程中涉及的线程。

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

__global__ void calcula_media(double *matriz, double *vet, int lin, int col) {
    int i=blockDim.x*blockIdx.x+threadIdx.x;
    int j=blockDim.y*blockIdx.y+threadIdx.y;

    if(i<lin && j<col) {
        vet[j]+=matriz[j*lin+i];
    }
}

int main(int argc, char **argv) {
    int i, j, lin, col;

    double *matriz, *media;
    double *matriz_d, *media_d;

    // Reads the dimensions of the matrix
    fscanf(stdin, "%d ", &lin);
    fscanf(stdin, "%d\n", &col);

    // Host variables
    cudaMallocHost((void **)&matriz, lin*col*sizeof(double));
    cudaMallocHost((void **)&media, col*sizeof(double));

    // Device variables
    cudaMalloc((void **)&matriz_d, lin*col*sizeof(double));
    cudaMalloc((void **)&media_d, col*sizeof(double));

    // Reads data from the input file
    for(i=0; i<lin; i++) {
        for(j=0; j<col; j++) {
            fscanf(stdin, "%lf ", &(matriz[j*lin+i]));
        }
    }

    // Copies content from matriz to matriz_d
    cudaMemcpy(matriz_d, matriz, lin*col*sizeof(double), cudaMemcpyHostToDevice);

    // Threads per block
    dim3 tpb(16, 16);

    // Grids per block
    dim3 bpg((lin*col+tpb.x-1)/tpb.x, (lin*col+tpb.y-1)/tpb.y);

    // Initializes media_d with zeros
    cudaMemset(media_d, 0, col*sizeof(double));

    // Launches the kernel
    calcula_media<<<bpg, tpb>>>(matriz_d, media_d, lin, col);

    // Copies the result back to media
    cudaMemcpy(media, media_d, col*sizeof(double), cudaMemcpyDeviceToHost);

    // Prints the result
    for(i=0; i<col; i++)
        printf("%.1lf ", media[i]);

    // Frees the allocated memory
    cudaFree(matriz);
    cudaFree(media);

    // Desaloca memória do device
    cudaFree(matriz_d);
    cudaFree(media_d);

    return 0;
}

对于此输入：

6 4
1 7 13 19
2 8 14 20
3 9 15 21
4 10 16 22
5 11 17 23
6 12 18 24

我希望输出为： 21.0 (the result of 1+2+...+6) 57.0 (the result of 7+8+...+12) 93.0 (the result of 13+14+...+18) 129.0 (the result of 19+20+...24)，

但实际输出为6.0 12.0 18.0 24.0。