Changes between Initial Version and Version 1 of mpich/collective_communication/demo1

Timestamp:

Jun 18, 2008, 5:50:07 PM (17 years ago)

Author:

wade

Comment:

--

mpich/collective_communication/demo1

@@ +1 @@
+= Source code =
+{{{
+/* Program:
+ *   每個 node 將自己運算後的結果傳回給 root node，而
+ *   root node 將結果印出
+ * History:
+ *   2008-06-10 BETA
+ */
+
+#include <stdio.h>
+#include <mpi.h>
+main (int argc, char **argv)
+{
+  int rank, size, i;
+  int myid, numprocs;
+  int myTotal = 0;
+  int Total = 0;
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
+  MPI_Comm_rank(MPI_COMM_WORLD, &myid);
+
+  for(i = 1; i <= 100; i++)
+  {
+    if((i % numprocs) == myid)
+    {
+      myTotal += i;
+    }
+    MPI_Reduce(&myTotal, &Total, 1, MPI_INT, MPI_SUM, 0,MPI_COMM_WORLD);
+  }
+  if(myid==0)
+  {
+    printf("Total = %d\n", Total);
+  }
+  MPI_Finalize();
+}
+
+}}}
+= Result =