Added a bunch of stuff.

EVI - 2016/EVI - 12/Examples/hello_mpi_yes_status.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <mpi.h>
+
+#define TAG 0 /* Message tag. */
+ 
+int main(int argc, char *argv[]) {
+  char * buff = NULL;
+  int rank;
+
+  /* Start with MPI_Init and get the rank. */
+  MPI_Init(&argc,&argv);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+  /***********************************************************************
+   * MASTER PROCESS                                                      *
+   ***********************************************************************/
+  if(rank == 0) {
+    int size, i;
+    
+    buff = (char *)calloc(128, sizeof(char));
+    
+    /* Get the number of processes. */
+    MPI_Comm_size(MPI_COMM_WORLD, &size);
+    printf("MASTER: %d processes available.\n", size);
+
+    /* Send data to the slaves. */
+    for(i = 1; i < size; i++) {
+      memset(buff, 0, 128);
+      sprintf(buff, "Hello, Process %d!", i);
+      MPI_Send(buff, strlen(buff) + 1, MPI_CHAR, i, TAG, MPI_COMM_WORLD);
+    }
+
+    /***********************************************************************
+     * SLAVE PROCESS                                                       *
+     ***********************************************************************/
+  } else {
+    MPI_Status status;
+    int data_size;
+    
+    /* Probe orders from the master. */
+    MPI_Probe(0 /*Master's rank*/, TAG, MPI_COMM_WORLD, &status);
+    
+    /* Find the amount of data sent by the master and allocate memory for it. */
+    MPI_Get_count(&status, MPI_CHAR, &data_size);
+    buff = (char *)calloc(data_size, sizeof(char));
+
+    /* Actually receive the data. */
+    MPI_Recv(buff, data_size, MPI_CHAR, 0 /*Master's rank*/, TAG, MPI_COMM_WORLD, &status);
+    printf("SLAVE %d: Master says: \"%s\"\n", rank, buff);
+  }
+  
+  /* Clean up. */
+  if(buff != NULL)
+    free(buff);
+  
+  /* End with MPI_Finalize. */
+  MPI_Finalize();
+  
+  return EXIT_SUCCESS;
+}