src/global_operations/print_tree.c

   1 /* skeleton for a broadcast routine from node 0 */
   2
   3 #include <stdio.h>
   4 #include <math.h>
   5 int main(int argc, char *argv[])
   6 {
   7         int two_to_generation;
   8         int rank, size;
   9         int to, from;
  10
  11         /* scan over a hypothetical virtual machine of 15 nodes */
  12         size = 15;
  13         for (rank = 0; rank < size; rank++) {
  14                 printf("rank %d", rank);
  15
  16                 /* two_to_generation reflects the steps in the tree broadcast */
  17                 two_to_generation = 1;
  18                 while (two_to_generation < size) {
  19
  20                         /* receive message */
  21                         if (rank >= two_to_generation
  22                             && rank < two_to_generation * 2) {
  23                                 from = rank - two_to_generation;
  24                                 if (from < size)
  25                                         printf(" -- from %d", from);
  26                         }
  27
  28                         /* send message */
  29                         if (rank < two_to_generation) {
  30                                 to = rank + two_to_generation;
  31                                 if (to < size)
  32                                         printf(" -- to %d", to);
  33                         }
  34                         two_to_generation = 2 * two_to_generation;
  35                 }
  36
  37                 /* done for a given rank */
  38                 printf("\n");
  39         }
  40 }