Initial version of core ch

This improves preprocessing times in favour of worse query performance.
Core size can be set over the --core parameater, default is the old
behaviour to fully contract the graph.

contractor/contractor.hpp

@@ -284,7 +284,7 @@ class Contractor
 
     ~Contractor() {}
 
-    void Run()
+    void Run( double core_factor = 1.0 )
     {
         // for the preperation we can use a big grain size, which is much faster (probably cache)
         constexpr size_t InitGrainSize = 100000;
@@ -333,9 +333,9 @@ class Contractor
                   << std::flush;
 
         bool flushed_contractor = false;
-        while (number_of_nodes > 2 && number_of_contracted_nodes < number_of_nodes)
+        while (number_of_nodes > 2 && number_of_contracted_nodes < static_cast<NodeID>(number_of_nodes * core_factor) )
         {
-            if (!flushed_contractor && (number_of_contracted_nodes > (number_of_nodes * 0.65)))
+            if (!flushed_contractor && (number_of_contracted_nodes > static_cast<NodeID>(number_of_nodes * 0.65 * core_factor)))
             {
                 DeallocatingVector<ContractorEdge> new_edge_set; // this one is not explicitely
                                                                  // cleared since it goes out of
@@ -524,7 +524,7 @@ class Contractor
             //            unsigned quaddegree = 0;
             //
             //            for(unsigned i = 0; i < remaining_nodes.size(); ++i) {
-            //                unsigned degree = contractor_graph->EndEdges(remaining_nodes[i].first)
+            //                unsigned degree = contractor_graph->EndEdges(remaining_nodes[i].id)
             //                -
             //                contractor_graph->BeginEdges(remaining_nodes[i].first);
             //                if(degree > maxdegree)
@@ -546,6 +546,8 @@ class Contractor
             p.printStatus(number_of_contracted_nodes);
         }
 
+        SimpleLogger().Write() << "[core] " << remaining_nodes.size() << " nodes " << contractor_graph->GetNumberOfEdges() << " edges." << std::endl;
+
         thread_data_list.data.clear();
     }
 

contractor/contractor_options.cpp

@@ -56,7 +56,11 @@ ContractorOptions::ParseArguments(int argc, char *argv[], ContractorConfig &cont
         "Path to LUA routing profile")(
         "threads,t", boost::program_options::value<unsigned int>(&contractor_config.requested_num_threads)
                          ->default_value(tbb::task_scheduler_init::default_num_threads()),
-        "Number of threads to use");
+        "Number of threads to use")(
+		"core,k", boost::program_options::value<double>(&contractor_config.core_factor)
+						 ->default_value(1.0),"Percentage of the graph (in vertices) to contract [0.1]");
+
+
 
     // hidden options, will be allowed both on command line and in config file, but will not be
     // shown to the user

contractor/contractor_options.hpp

@@ -56,6 +56,12 @@ struct ContractorConfig
     std::string rtree_leafs_output_path;
 
     unsigned requested_num_threads;
+
+    //A percentage of vertices that will be contracted for the hierarchy.
+    //Offers a trade-off between preprocessing and query time.
+    //The remaining vertices form the core of the hierarchy 
+    //(e.g. 0.8 contracts 80 percent of the hierarchy, leaving a core of 20%)
+    double core_factor;
 };
 
 struct ContractorOptions

contractor/processing_chain.cpp

@@ -414,7 +414,7 @@ void Prepare::ContractGraph(const unsigned max_edge_id,
                             DeallocatingVector<QueryEdge>& contracted_edge_list)
 {
     Contractor contractor(max_edge_id + 1, edge_based_edge_list);
-    contractor.Run();
+    contractor.Run(config.core_factor);
     contractor.GetEdges(contracted_edge_list);
 }