--- trunk/OOPSE/libmdtools/DumpWriter.cpp	2004/01/08 18:59:36	912
+++ trunk/OOPSE/libmdtools/DumpWriter.cpp	2004/01/08 22:25:52	913
@@ -158,10 +158,15 @@ void DumpWriter::writeDump( double currentTime ){
 
 #else // is_mpi
 
-  // first thing first, suspend fatalities.
-  painCave.isEventLoop = 1;
+  /* code to find maximum tag value */
+  int *tagub, flag, MAXTAG;
+  MPI_Attr_get(MPI_COMM_WORLD, MPI_TAG_UB, &tagub, &flag);
+  if (flag) {
+    MAXTAG = *tagub;
+  } else {
+    MAXTAG = 32767;
+  }
 
-  int myStatus; // 1 = wakeup & success; 0 = error; -1 = AllDone
   int haveError;
 
   MPI_Status istatus;
@@ -188,18 +193,24 @@ void DumpWriter::writeDump( double currentTime ){
     outFile << entry_plug->the_integrator->getAdditionalParameters();
     outFile << endl;
     outFile.flush();
+
+    tag = 0;
+
     for (i = 0 ; i < mpiSim->getTotAtoms(); i++ ) {
-      // Get the Node number which has this atom;
 
+      if (tag + 2 >= MAXTAG) {
+	// The tag was going to exceed the maximum value, so wrap around to 0:
+	tag = 0;
+	// Send the newly zeroed tag on to the other nodes:
+	MPI_Bcast(&tag, 1, MPI_INT, 0, MPI_COMM_WORLD);
+      }
+      
+      // Get the Node number which has this atom;
+      
       which_node = AtomToProcMap[i];
-
+      
       if (which_node != 0) {
         
-        atomTypeTag          = 4*i;
-        atomIsDirectionalTag = 4*i + 1;
-        atomTransDataTag     = 4*i + 2;
-        atomOrientDataTag    = 4*i + 3;
-
         MPI_Recv(MPIatomTypeString, MINIBUFFERSIZE, MPI_CHAR, which_node,
 		 atomTypeTag, MPI_COMM_WORLD, &istatus);