protected void initializeSEs() {
   for (int i = 0; i < this.getNumSEs(); i++) {
     GridElement storageElement = (GridElement) Sim_system.get_entity("SE_" + i);
     this.mapSEs.put(storageElement.get_id(), storageElement.getExternalRouter());
     this.getSEs().add(storageElement);
   }
 }
 protected void initializeCEs() {
   @SuppressWarnings("unused")
   int N = this.getTopology().getNumRouters();
   for (int i = 0; i < this.getNumCEs(); i++) {
     GridElement computingElement = (GridElement) Sim_system.get_entity("CE_" + i);
     this.mapCEs.put(computingElement.get_id(), computingElement.getExternalRouter());
     this.getCEs().add(computingElement);
   }
 }