我正在学习如何使用MPI。
现在我要做的就是在主任务和从任务之间发送和接收数据。将数据从主任务发送到从任务可以正常工作。 (我通过让每个从站打印从主站接收的数据来测试它。)
从奴隶任务接收主任务中的数据似乎不起作用。
#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MASTER_TAG 0
#define WORKTAG 1
#define DIETAG 2
#define N 4
#define ARRAY_SIZE N*N
int getMin(int a, int b);
void print1D(int *arr, int n);
int* allocateIntegerArray(int n);
void master();
void slave();
int *inputArray = NULL;
int *outputArray = NULL;
int main(int argc, char **argv)
{
int myrank = 0;
MPI_Init(&argc, &argv); // initialize MPI
MPI_Comm_rank(MPI_COMM_WORLD, &myrank); // process rank, 0 thru N-1
if (myrank == 0)
master();
else
slave();
MPI_Finalize(); // cleanup MPI
return 0;
}
void master()
{
int numOfTasks;
int rank = 0;
int work = 0;
int startIndex = 0;
int dataPerTask = 0;
int *tempArray = NULL;
int i = 0;
int k = 0;
MPI_Status status;
MPI_Comm_size( MPI_COMM_WORLD, &numOfTasks); // #processes in application
// calculate the amount of data that each task will receive
dataPerTask = ARRAY_SIZE;
// create the array that will hold the data that will be transferred back and forth between the master and slave tasks
tempArray = allocateIntegerArray( dataPerTask );
for (i = 1; i < numOfTasks; ++i)
{
MPI_Send(&dataPerTask, 1, MPI_INT, i, WORKTAG, MPI_COMM_WORLD); // send the size of the data chunk to the slave task
MPI_Send(tempArray, dataPerTask, MPI_INT, i, WORKTAG, MPI_COMM_WORLD); // send the actual chunk of data to the slave task
print1D(tempArray, dataPerTask);
MPI_Recv(tempArray, dataPerTask, MPI_INT, MPI_ANY_TAG, WORKTAG, MPI_COMM_WORLD, &status); // receive results from slave task
print1D(tempArray, dataPerTask);
}
// tell all the slaves to exit
for (i = 1; i < numOfTasks; ++i)
MPI_Send(0, 0, MPI_INT, i, DIETAG, MPI_COMM_WORLD);
free(tempArray);
}
void slave()
{
MPI_Status status;
int *in = NULL; // input array
int *out = NULL; // outpu array
int dataPerTask = 0;
for (;;)
{
MPI_Recv(&dataPerTask, 1, MPI_INT, MASTER_TAG, MPI_ANY_TAG, MPI_COMM_WORLD, &status); // get the number of integers in the incoming array
if (status.MPI_TAG == DIETAG) // check the tag of the received message (if the master task sent the DIETAG, then the slave must stop processing and return)
return;
in = allocateIntegerArray(dataPerTask); // array 'in' holds the data received from the master task
out = allocateIntegerArray(dataPerTask); // array 'out' holds the data that is returned to the master task
MPI_Recv(in, dataPerTask, MPI_INT, MASTER_TAG, MPI_ANY_TAG, MPI_COMM_WORLD, &status); // get the actual data from the master task
out[0] = 1; // modify the data in some way
MPI_Send(out, dataPerTask, MPI_INT, 0, WORKTAG, MPI_COMM_WORLD);
}
free(in);
free(out);
}
void print1D(int *arr, int n)
{
int i = 0;
for (i = 0; i < n; i++)
printf("%d ", arr[i]);
printf("\n");
}
int* allocateIntegerArray(int n)
{
int i = 0;
if (n <= 0)
return NULL;
int *arr = (int*) malloc(sizeof(int)*n*n);
memset(arr, 0, sizeof(int)*n*n);
return arr;
}
答案 0 :(得分:3)
根本原因是您的程序调用{{1}}
MPI_Recv(...,source=MPI_ANY_TAG, ...)
不是有效来源,您应该使用正确的来源(例如MPI_ANY_TAG
中的i
和master
中的0
)或{ {1}}。
FWIW,不认为这是理所当然的,因为它可能在将来发生变化
slave
中,MPI_ANY_SOURCE
和Open MPI
具有相同的价值,这就是我最初认为它对我有用的原因。MPI_ANY_SOURCE
中,MPI_ANY_TAG
的值与MPICH
相同,这就是为什么邮件在您的环境中只有零。