Push-relabel adjacency as reference

bnb/push_relabel.cpp

@@ -5,6 +5,9 @@
 push_relabel::push_relabel(const graph &g, std::vector<node_id> sources, std::vector<node_id> sinks) 
     : g_(g), sources_(sources), sinks_(sinks) {
 
+	// Initial flow value
+	flow_value_ = 0;
+
     int num_nodes = g_.num_nodes();
 
     // Initialize all vectors
@@ -41,7 +44,7 @@ void push_relabel::relabel(node_id u) {
 
     int d = std::numeric_limits<int>::max();
 
-    std::vector<node_id> neighbors = g_.get_adjacency(u);
+    const std::vector<node_id> & neighbors = g_.get_adjacency(u);
 
     for (auto v : neighbors) {
         if (1 - flow_[u][v] > 0)
@@ -58,7 +61,7 @@ void push_relabel::discharge(node_id u) {
 
     while (excess_[u] > 0) {
 
-        std::vector<node_id> neighbors = g_.get_adjacency(u);
+        const std::vector<node_id> & neighbors = g_.get_adjacency(u);
 
         bool push_possible = false;
         for (auto v : neighbors) {
@@ -87,7 +90,7 @@ void push_relabel::preflow() {
     }
 
     for (node_id s : sources_) {
-        std::vector<node_id> neighbors = g_.get_adjacency(s);
+        const std::vector<node_id> & neighbors = g_.get_adjacency(s);
         for (auto n : neighbors) {
             if (sources_and_sinks_[n] != 1) // if n is not a source node
                 push(s, n);
@@ -109,7 +112,6 @@ void push_relabel::run() {
     }
 
     // Flow value is the sum of excesses in sinks
-    flow_value_ = 0;
     for (node_id t : sinks_)
         flow_value_ += excess_[t];
         

include/gp-bnb/push_relabel.hpp

@@ -30,22 +30,21 @@ private:
 
 public:
 	/**
-	 * Constructs an instance of the EdmondsKarp algorithm for the given graph, source and sink
+	 * Constructs an instance of the Push-Realbel algorithm for the given graph, sources and sinks
 	 * @param graph The graph.
-	 * @param source The source node.
-	 * @param sink The sink node.
+	 * @param sources Vector of source nodes.
+	 * @param sinks Vector of sink nodes.
 	 */
 	push_relabel(const graph &g, std::vector<node_id> sources, std::vector<node_id> sinks);
 
 	/**
-	 * Computes the maximum flow, executes the EdmondsKarp algorithm.
+	 * Computes the maximum flow, executes the Peush-Relabel algorithm with discharge.
 	 * For unweighted, undirected Graphs.
 	 */
 	void run();
 
 	/**
-	 * Returns the value of the maximum flow from source to sink.
-	 *
+	 * Returns the value of the maximum flow from sources to sinks.
 	 * @return The maximum flow value
 	 */
 	int get_max_flow() const;