// find the commodities in the traffic matrix

*operation* Commodity_List* find_commodities(Node_List* nodelist, Ring* ring)
*init* (@ new Commodity_List() @)
*traverse*
  *from* InputNetwork
  *through* -> *, neighbors, *
  *to-stop* InputNode
*carry* *in* Node* source_node
*along*
  *from* InputAdjacency
  *through* -> *, neighbors, *
  *to-stop* InputNode
*carry* *in* DemReal* traffic
*along*
  *from* InputNeighbor
  *to-stop* InputNode
*at* InputNeighbor traffic = (@ get_capacity() @)
*wrapper* InputAdjacency
  (@
     int pos = nodelist->id_member(get_source());
     source_node = nodelist->n_th(pos);
   @)
*wrapper* InputNode
  (@
     int pos = nodelist->id_member(this);
     Node* dest_node = nodelist->n_th(pos);
     VNode *source_vnode, *dest_vnode;
     ring->distance(source_node, dest_node, source_vnode, dest_vnode);
     Commodity* com = return_val->dest_member(dest_vnode);
     VNodeTraff* new_vnodetraff = new VNodeTraff(source_vnode, traffic); 
     if (com == NULL) {
       com = new Commodity(dest_vnode, new VNodeTraff_List());
       com->get_sources()->append(new_vnodetraff);
       return_val->append(com);
     }
     else {
       com->get_sources()->append(new_vnodetraff);
     }
   @)


// return the Commodity that has destination "vnode".

*operation* Commodity* dest_member(VNode* vnode)
*init* (@ NULL @)
*traverse*
  *from* Commodity_List
  *through* -> *, dest, *
  *to-stop* VNode
*carry* *in* Commodity* com
*along*
  *from* Commodity
  *through* -> *, dest, *
  *to-stop* VNode
*at* Commodity com = (@ this @)
*wrapper* VNode
  (@
     if (this == vnode)
       return_val = com;
   @)


*operation* void print_commodities()
*traverse*
  *from* Commodity_List
  *to* VNodeTraff
*wrapper* Commodity
  (@
     cout << "Commodity: " << get_dest()->get_vid() << endl;
   @)
*wrapper* VNodeTraff
  (@
   cout << "   " << get_source()->get_vid() << " with " << get_traffic() << endl;
   @)