Forgot bcast is not synchronous, so we need a barrier to stop loops running ahead

mpiuse.c

@@ -197,8 +197,10 @@ void mpiuse_dump_logs(int nranks, const char *dumpfile) {
      * one-by-one. */
     int kk = k;
     MPI_Bcast(&kk, 1, MPI_INT, 0, MPI_COMM_WORLD);
+    message("Bcast says: %d/%d/%d", kk, k, myrank);
 
-    if (k == myrank) {
+    if (kk == myrank) {
+        message("Dumping from rank: %d/%d/%d", kk, k, myrank);
 
       /* Open file and position at end. */
       fd = fopen(dumpfile, "a");
@@ -223,6 +225,9 @@ void mpiuse_dump_logs(int nranks, const char *dumpfile) {
       }
       fclose(fd);
     }
+
+    /* Need to stay in step. */
+    MPI_Barrier(MPI_COMM_WORLD);
   }
 }