bcast

bcast/main.cc

@@ -0,0 +1,44 @@
+#include <mpi.h>
+#include <string>
+#include <cstring>
+#include <functional>
+#include <iostream>
+
+int main(int argc, char *argv[]) {
+  int rank, size;
+  char proc_name[2048];
+  int proc_name_len;
+  MPI_Comm node, head;
+  MPI_Init(&argc, &argv);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+  MPI_Comm_size(MPI_COMM_WORLD, &size);
+  // node comm
+  MPI_Get_processor_name(proc_name, &proc_name_len);
+  std::string proc_name_str(proc_name, proc_name_len);
+  int proc_name_hash = std::hash<std::string>{}(proc_name_str);
+  // std::cout << proc_name_str << ", " << proc_name_hash << std::endl;
+  MPI_Comm_split(MPI_COMM_WORLD, proc_name_hash, -1, &node);
+  int node_rank, node_size;
+  MPI_Comm_rank(node, &node_rank);
+  MPI_Comm_size(node, &node_size);
+  // head comm
+  int head_rank, head_size;
+  int headornot = node_rank == 0;
+  MPI_Comm_split(MPI_COMM_WORLD, headornot, -1, &head);
+  MPI_Comm_rank(head, &head_rank);
+  MPI_Comm_size(head, &head_size);
+  //std::cout << "rank:" << rank << ", head_rank:" << head_rank << ", head_size:" << head_size << std::endl;
+  char message[2048] = "default string";
+  printf("rank:%d, is_head:%d, node:%s, node_rank:%d, msg:%s\n", rank, headornot, proc_name, node_rank, message);
+  // bcast in head
+  if (head_rank == 0 && headornot) {
+    strcpy(message, "hello from root");
+  }
+  if (headornot) {
+    MPI_Bcast((void*) message, 16, MPI_CHAR, 0, head);
+  }
+  // bcast in node
+  MPI_Bcast((void*) message, 16, MPI_CHAR, 0, node);
+  printf("rank:%d, is_head:%d, node:%s, node_rank:%d, msg:%s\n", rank, headornot, proc_name, node_rank, message);
+  MPI_Finalize();
+}