fixing lookahead issue in conservative mode caused by zero timestamp events in model-net

codes/net/dragonfly.h

@@ -38,6 +38,9 @@ struct terminal_message
   short saved_vc;
   /* last hop of the message, can be a terminal, local router or global router */
   short last_hop;
+
+  /* for reverse computation */
+  short path_type;
   // For buffer message
    short vc_index;
    int input_chan;

src/models/networks/model-net/model-net-lp.c

@@ -225,7 +225,7 @@ void handle_new_msg(
     
     if (ns->in_sched_loop == 0){
         b->c0 = 1;
-        tw_event *e = codes_event_new(lp->gid, codes_local_latency(lp), lp);
+        tw_event *e = codes_event_new(lp->gid, g_tw_lookahead + codes_local_latency(lp), lp);
         model_net_wrap_msg *m = tw_event_data(e);
         m->event_type = MN_BASE_SCHED_NEXT;
         m->magic = model_net_base_magic;
@@ -265,7 +265,7 @@ void handle_sched_next(
     }
     else {
         tw_event *e = codes_event_new(lp->gid, 
-                poffset+codes_local_latency(lp), lp);
+                poffset+codes_local_latency(lp) + g_tw_lookahead, lp);
         model_net_wrap_msg *m = tw_event_data(e);
         m->event_type = MN_BASE_SCHED_NEXT;
         m->magic = model_net_base_magic;

src/models/networks/model-net/model-net.c

@@ -178,7 +178,7 @@ static void model_net_event_impl_base(
     }
 
     tw_lpid mn_lp = model_net_find_local_device(net_id, sender);
-    tw_stime poffset = codes_local_latency(sender);
+    tw_stime poffset = g_tw_lookahead + codes_local_latency(sender);
     if (in_sequence){
         tw_stime tmp = mn_msg_offset;
         mn_msg_offset += poffset;