public Elem(Graph.Node node, double dist, Graph.Node prev, Graph.Edge edge)
{
this.node = node;
this.dist = dist;
this.prev = prev;
this.edge = edge;
if (edge != null)
{
HDebug.Assert(edge.nodes.Length == 2);
HDebug.Assert(edge.nodes.Contains(node));
HDebug.Assert(edge.nodes.Contains(prev));
}
}
public static Elem[] BuildMinAlt(Graph graph, Dictionary <Graph.Node, double> source2initdist, Func <double, Graph.Node, Graph.Edge, Graph.Node, double> GetAlt, Func <Graph.Node, bool> IsTarget)
{
/// dist(v2) := min[dist(v2), alt[dist(v1), dist(v1-v2)]]
int maxid = 0;
foreach (Graph.Node node in graph.Nodes)
{
maxid = Math.Max(maxid, node.id);
}
int size = maxid + 1;
//double maxdist = edge_dist.Values.Max() + 100;
Elem[] elems = new Elem[size];
Dictionary <Graph.Node, Graph.Node> prev = new Dictionary <Graph.Node, Graph.Node>();
foreach (Graph.Node node in graph.Nodes)
{
elems[node.id] = new Elem(node, double.PositiveInfinity, null, null);
}
foreach (Graph.Node source in source2initdist.Keys)
{
double initdist = source2initdist[source];
HDebug.Assert(initdist >= 0);
HDebug.Assert(elems[source.id] != null, elems[source.id].node == source);
elems[source.id] = new Elem(source, initdist, null, null);
}
SortedSet <Elem> Q = new SortedSet <Elem>(new Elem(null, double.NaN, null, null));
foreach (Graph.Node node in graph.Nodes)
{
Q.Add(elems[node.id]);
}
while (Q.Count > 0)
{
Elem u = Q.Min;
Q.Remove(u);
if ((IsTarget != null) && (IsTarget(u.node)))
{
return(elems);
}
if (double.IsInfinity(u.dist))
//if(u.dist > maxdist)
{
elems[u.node.id] = new Elem(u.node, double.PositiveInfinity, null, null);
continue;
}
foreach (Graph.Node v_node in u.node.nexts.Keys)
{
Graph.Edge uv_edge = u.node.nexts[v_node];
double alt = GetAlt(u.dist, u.node, uv_edge, v_node);
HDebug.Assert(alt >= u.dist);
if (alt < elems[v_node.id].dist)
{
Q.Remove(elems[v_node.id]);
elems[v_node.id] = new Elem(v_node, alt, u.node, uv_edge);
Q.Add(elems[v_node.id]);
}
}
}
return(elems);
}
