与 MPI 共享动态分配的二维数组
Sharing a dynamically allocated 2D array with MPI
我正在尝试在一个函数内使用 c 中的 MPI 将主线程中动态分配的二维数组共享给其他几个线程。
相关代码简化表示如下:
//Initialize program, start up the desired number of threads.
//Master thread takes input from user, dynamically allocates and constructs 2d array.
//All threads call method analyze_inputs(**array), which takes the array as input (all threads other than master simply pass NULL as argument)
//The master thread shares the array, along with work division to all other threads:
{//Master thread
MPI_Send(&x, 1, MPI_INT, recievingThread, 0, MPI_COMM_WORLD);
MPI_Send(&y, 1, MPI_INT, recievingThread, 0, MPI_COMM_WORLD);
MPI_Send(&(array[0][0]), x*y, MPI_INT, recievingThread, 0, MPI_COMM_WORLD);
}
{//Subthreads
MPI_Recv(&x, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
MPI_Recv(&y, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
MPI_Recv(&(array[0][0]), x*y, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
}
这是我在此站点上找到的用于发送动态分配的二维数组的解决方案,但我收到数组接收的分段错误。
我该怎么做?
编辑:最小可重现示例
#include <mpi.h>
#include <stdlib.h>
#include <stdio.h>
int analyze_inputs (int x, int y, int** array);
int main (int argc, char **argv)
{
int x = 10;
int y = 8;
int rank;
int **array = NULL;
MPI_Init (&argc, &argv);
MPI_Comm_rank (MPI_COMM_WORLD, &rank);
if (rank == 0)
{
array = malloc(x * sizeof(int*));
for (int i = 0; i < x; i++)
{
array[i] = malloc(y * sizeof(int));
}
for (int i = 0; i < x; i++)
{
for (int j = 0; j < y; j++)
{
array[i][j] = rand();
}
}
}
analyze_inputs(x,y,array);
MPI_Finalize ();
}
int analyze_inputs(int x,int y, int** array)
{
int rank, x_temp, y_temp, **array_temp;
MPI_Comm_rank (MPI_COMM_WORLD, &rank);
if (rank == 0)
{
MPI_Send(&x, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
MPI_Send(&y, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
MPI_Send(&(array[0][0]), x*y, MPI_INT, 1, 0, MPI_COMM_WORLD);
}
else
{
MPI_Recv(&x_temp, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
MPI_Recv(&y_temp, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("Works to here.\n");
MPI_Recv(&(array_temp[0][0]), x_temp*y_temp, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("Crashes before here.\n");
}
}
每一行array
在你的代码中单独分配,如此简单
MPI_Send(&(array[0][0]), x*y, MPI_INT, 1, 0, MPI_COMM_WORLD);
在这种情况下不起作用。
一个简单的解决方案是像这样分配一个内存块:
array = malloc(x * sizeof(int*));
array[0] = malloc(y * x * sizeof(int));
for (int i = 1; i < x; i++)
{
array[i] = array[0] + y * i;
}
释放这个数组将是
free(array[0]);
free(array);
不要释放 array[1]
、array[2]
、...在这种情况下,因为它们已经被 free(array[0]);
释放。
我正在尝试在一个函数内使用 c 中的 MPI 将主线程中动态分配的二维数组共享给其他几个线程。
相关代码简化表示如下:
//Initialize program, start up the desired number of threads.
//Master thread takes input from user, dynamically allocates and constructs 2d array.
//All threads call method analyze_inputs(**array), which takes the array as input (all threads other than master simply pass NULL as argument)
//The master thread shares the array, along with work division to all other threads:
{//Master thread
MPI_Send(&x, 1, MPI_INT, recievingThread, 0, MPI_COMM_WORLD);
MPI_Send(&y, 1, MPI_INT, recievingThread, 0, MPI_COMM_WORLD);
MPI_Send(&(array[0][0]), x*y, MPI_INT, recievingThread, 0, MPI_COMM_WORLD);
}
{//Subthreads
MPI_Recv(&x, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
MPI_Recv(&y, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
MPI_Recv(&(array[0][0]), x*y, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
}
这是我在此站点上找到的用于发送动态分配的二维数组的解决方案,但我收到数组接收的分段错误。
我该怎么做?
编辑:最小可重现示例
#include <mpi.h>
#include <stdlib.h>
#include <stdio.h>
int analyze_inputs (int x, int y, int** array);
int main (int argc, char **argv)
{
int x = 10;
int y = 8;
int rank;
int **array = NULL;
MPI_Init (&argc, &argv);
MPI_Comm_rank (MPI_COMM_WORLD, &rank);
if (rank == 0)
{
array = malloc(x * sizeof(int*));
for (int i = 0; i < x; i++)
{
array[i] = malloc(y * sizeof(int));
}
for (int i = 0; i < x; i++)
{
for (int j = 0; j < y; j++)
{
array[i][j] = rand();
}
}
}
analyze_inputs(x,y,array);
MPI_Finalize ();
}
int analyze_inputs(int x,int y, int** array)
{
int rank, x_temp, y_temp, **array_temp;
MPI_Comm_rank (MPI_COMM_WORLD, &rank);
if (rank == 0)
{
MPI_Send(&x, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
MPI_Send(&y, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
MPI_Send(&(array[0][0]), x*y, MPI_INT, 1, 0, MPI_COMM_WORLD);
}
else
{
MPI_Recv(&x_temp, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
MPI_Recv(&y_temp, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("Works to here.\n");
MPI_Recv(&(array_temp[0][0]), x_temp*y_temp, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("Crashes before here.\n");
}
}
每一行array
在你的代码中单独分配,如此简单
MPI_Send(&(array[0][0]), x*y, MPI_INT, 1, 0, MPI_COMM_WORLD);
在这种情况下不起作用。
一个简单的解决方案是像这样分配一个内存块:
array = malloc(x * sizeof(int*));
array[0] = malloc(y * x * sizeof(int));
for (int i = 1; i < x; i++)
{
array[i] = array[0] + y * i;
}
释放这个数组将是
free(array[0]);
free(array);
不要释放 array[1]
、array[2]
、...在这种情况下,因为它们已经被 free(array[0]);
释放。