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Send a random number from the master node to all the slave nodes (http://techtinkering.com/2009/12/02/setting-up-a-beowulf-cluster-using-open-mpi-on-linux/)
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| FROM ubuntu | |
| RUN apt-get update | |
| RUN apt-get install -y gcc openssh-client wget openmpi-bin openmpi-common libopenmpi1.3 libopenmpi-dev | |
| RUN wget --no-check-certificate https://gist.githubusercontent.com/rwl/b1ae2fd3908901b367b7/raw/5218b661332b4a41c752807a2258c8fdfa856a21/testprog.c | |
| RUN mpicc testprog.c | |
| RUN mpirun -np 10 ./a.out |
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| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <mpi.h> | |
| int main(int argc, char *argv[]) | |
| { | |
| const int MASTER = 0; | |
| const int TAG_GENERAL = 1; | |
| int numTasks; | |
| int rank; | |
| int source; | |
| int dest; | |
| int rc; | |
| int count; | |
| int dataWaitingFlag; | |
| char inMsg; | |
| char outMsg; | |
| MPI_Status Stat; | |
| // Initialize the MPI stack and pass 'argc' and 'argv' to each slave node | |
| MPI_Init(&argc,&argv); | |
| // Gets number of tasks/processes that this program is running on | |
| MPI_Comm_size(MPI_COMM_WORLD, &numTasks); | |
| // Gets the rank (process/task number) that this program is running on | |
| MPI_Comm_rank(MPI_COMM_WORLD, &rank); | |
| // If the master node | |
| if (rank == MASTER) { | |
| // Send out messages to all the sub-processes | |
| for (dest = 1; dest < numTasks; dest++) { | |
| outMsg = rand() % 256; // Generate random message to send to slave nodes | |
| // Send a message to the destination | |
| rc = MPI_Send(&outMsg, 1, MPI_CHAR, dest, TAG_GENERAL, MPI_COMM_WORLD); | |
| printf("Task %d: Sent message %d to task %d with tag %d\n", | |
| rank, outMsg, dest, TAG_GENERAL); | |
| } | |
| } | |
| // Else a slave node | |
| else { | |
| // Wait until a message is there to be received | |
| do { | |
| MPI_Iprobe(MASTER, 1, MPI_COMM_WORLD, &dataWaitingFlag, MPI_STATUS_IGNORE); | |
| printf("Waiting\n"); | |
| } while (!dataWaitingFlag); | |
| // Get the message and put it in 'inMsg' | |
| rc = MPI_Recv(&inMsg, 1, MPI_CHAR, MASTER, TAG_GENERAL, MPI_COMM_WORLD, &Stat); | |
| // Get how big the message is and put it in 'count' | |
| rc = MPI_Get_count(&Stat, MPI_CHAR, &count); | |
| printf("Task %d: Received %d char(s) (%d) from task %d with tag %d \n", | |
| rank, count, inMsg, Stat.MPI_SOURCE, Stat.MPI_TAG); | |
| } | |
| MPI_Finalize(); | |
| } |
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