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copied!<p>As somebody already wrote, you can use <code>MPI_ANY_SOURCE</code> to receive from any source. To send two different kind of data in a single send you can use a <a href="http://www.mpi-forum.org/docs/mpi-11-html/node54.html" rel="nofollow">derived datatype</a>:</p> <pre><code>#include <stdio.h> #include <stdlib.h> #include "mpi.h" #define asize 10 typedef struct data_ { int id; float array[asize]; } data; int main() { MPI_Init(NULL,NULL); int rank = -1; int size = -1; MPI_Comm_rank(MPI_COMM_WORLD,&rank); MPI_Comm_size(MPI_COMM_WORLD,&size); data buffer; // Define and commit a new datatype int blocklength [2]; MPI_Aint displacement[2]; MPI_Datatype datatypes [2]; MPI_Datatype mpi_tdata; MPI_Aint startid,startarray; MPI_Get_address(&(buffer.id),&startid); MPI_Get_address(&(buffer.array[0]),&startarray); blocklength [0] = 1; blocklength [1] = asize; displacement[0] = 0; displacement[1] = startarray - startid; datatypes [0] = MPI_INT; datatypes [1] = MPI_FLOAT; MPI_Type_create_struct(2,blocklength,displacement,datatypes,&mpi_tdata); MPI_Type_commit(&mpi_tdata); if (rank == 0) { int count = 0; MPI_Status status; while (count < size-1 ) { // Non-blocking receive printf("Receiving message %d\n",count); MPI_Recv(&buffer,1,mpi_tdata,MPI_ANY_SOURCE,0,MPI_COMM_WORLD,&status); printf("Message tag %d, first entry %g\n",buffer.id,buffer.array[0]); // Counting the received messages count++; } } else { // Initialize buffer to be sent buffer.id = rank; for (int ii = 0; ii < size; ii++) { buffer.array[ii] = 10*rank + ii; } // Send buffer MPI_Send(&buffer,1,mpi_tdata,0,0,MPI_COMM_WORLD); } MPI_Type_free(&mpi_tdata); MPI_Finalize(); return 0; } </code></pre>

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