Initial commit

Basecode.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <mpi.h>
+
+#define USE_DERIVED_DATATYPE 1
+
+void PrintMPIError(int err, int my_rank) {
+	int eclass, len;
+	char estring[MPI_MAX_ERROR_STRING];
+
+	MPI_Error_class(err, &eclass);
+	MPI_Error_string(err, estring, &len);
+	printf("P%d Error %d: %s\n", my_rank, eclass, estring);fflush(stdout);
+}
+
+void MakePacket(int *buffer1, double *buffer2, int elems, int my_rank, MPI_Datatype *new_type) {
+	int k, err, lblq[2];
+	MPI_Aint dspl[2];
+	MPI_Datatype type[2];
+		
+	type[0] = MPI_INT   ; lblq[0] = elems ; MPI_Get_address(buffer1, &dspl[0]);
+	type[1] = MPI_DOUBLE; lblq[1] = elems ; MPI_Get_address(buffer2, &dspl[1]);
+	for (k=1; k>=0; k--) dspl[k] -= dspl[0]; 
+	// Creation of the packet
+	err = MPI_Type_create_struct (2, lblq, dspl, type, new_type);
+	if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	err = MPI_Type_commit(new_type);
+	if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+}
+
+int main(int argc, char* argv[])
+{
+    MPI_Init(&argc, &argv);
+
+    // Size of the default communicator
+    int size, my_rank;
+    int tag, elems, use_derived, err;
+    MPI_Datatype new_type;
+    tag = 210;
+    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &size);
+
+    char processor_name[MPI_MAX_PROCESSOR_NAME];
+    int name_len;
+    MPI_Get_processor_name(processor_name, &name_len);
+
+    use_derived = USE_DERIVED_DATATYPE;
+    // Get my rank and do the corresponding job
+    switch(my_rank)
+    {
+        case 0:
+        { 
+	    printf("P%d at node %s\n", my_rank, processor_name);
+	    elems = 752;
+            int *buffer1 = (int*) malloc(elems * sizeof(int));
+            double *buffer2 = (double*) malloc(elems * sizeof(double));
+
+	    if(use_derived)
+	    {
+              MakePacket(buffer1, buffer2, elems, my_rank, &new_type);
+              err = MPI_Send(buffer1, 1, new_type, 2, tag, MPI_COMM_WORLD);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	      sleep(1);
+              err = MPI_Send(buffer1, 1, new_type, 1, tag, MPI_COMM_WORLD);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	      err = MPI_Type_free(&new_type);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	    } else 
+	    {
+              MPI_Send(buffer1, elems, MPI_INT, 2, tag, MPI_COMM_WORLD);
+	      sleep(1);
+              MPI_Send(buffer1, elems, MPI_INT, 1, tag, MPI_COMM_WORLD);
+	    }
+            break;
+        }
+        case 1: // This rank is in a different machine than rank 0
+	    sleep(2);
+        case 2: // This rank is in the same machine than rank 0
+        {
+            printf("P%d at node %s\n", my_rank, processor_name);
+
+            // Retrieve information about the incoming message
+            MPI_Status status;
+            err = MPI_Probe(0, tag, MPI_COMM_WORLD, &status);
+	    if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+
+            // Get the number of elements in the message probed
+            int count, tam_int, tam_double;
+	    if(use_derived)
+	    {
+	      err = MPI_Get_count(&status, MPI_BYTE, &count);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	      err = MPI_Type_size(MPI_INT, &tam_int);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	      err = MPI_Type_size(MPI_DOUBLE, &tam_double);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	      elems = count / (tam_int + tam_double);
+//	      elems = 752;
+	    }
+	    else
+	    {
+	      MPI_Get_count(&status, MPI_INT, &count);
+	      elems=count;
+	    }
+
+	    printf("P%d: Total expected counts=%d elems=%d\n", my_rank, count, elems);
+            // Allocate the buffer now that we know how many elements there are
+            int* buffer1 = (int*) malloc(elems * sizeof(int));
+            double *buffer2 = (double*) malloc(elems * sizeof(double));
+
+	    // Receive the message
+	    if(use_derived)
+	    {
+              MakePacket(buffer1, buffer2, elems, my_rank, &new_type);
+              err = MPI_Recv(buffer1, 1, new_type, 0, tag, MPI_COMM_WORLD, &status);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	      err = MPI_Type_free(&new_type);
+	      if (err != MPI_SUCCESS) PrintMPIError(err, my_rank);
+	    }
+	    else
+	    { 
+              MPI_Recv(buffer1, elems, MPI_INT, 0, tag, MPI_COMM_WORLD, &status);
+	    }
+            printf("P%d: received message with %d elements\n", my_rank, elems);
+            break;
+        }
+	default:
+	{
+	    break;
+	}
+    }
+
+    MPI_Finalize();
+    return EXIT_SUCCESS;
+}