/// <summary>
/// Instantiates a new MinimalSpanningTree.
/// </summary>
/// <param name="mstNodes">The GraphNodes that should be spanned.</param>
/// <param name="distances">An optional DistanceLookup parameter which
/// caches the found node-node distances.</param>
public MinimalSpanningTree(HashSet <GraphNode> mstNodes, DistanceLookup distances = null)
{
// Copy might be preferable, doesn't really matter atm though.
this.mstNodes = mstNodes;
this.distances = (distances == null ? new DistanceLookup() : distances);
_isSpanned = false;
}
public void TestDijkstra()
{
// TODO: Maybe make the graphs class members.
/// 0 -- 1 -- 2 -- 3
/// \ | /
/// \ | /
/// 4 -- 5
bool[,] graph1 = {
{ false, true, false, false, true, false },
{ true, false, true, false, false, false },
{ false, true, false, true, false, true },
{ false, false, true, false, false, true },
{ true, false, false, false, false, true },
{ false, false, true, true, true, false },
};
SearchGraph searchGraph1 = SearchGraphFromData(graph1);
Dictionary<int, GraphNode> graphNodes = GetGraphNodesIdIndex(searchGraph1);
DistanceLookup distanceLookup = new DistanceLookup();
Assert.IsTrue(distanceLookup.GetDistance(graphNodes[0], graphNodes[0]) == 0, "Failed 0 distance test");
Assert.IsTrue(distanceLookup.GetDistance(graphNodes[0], graphNodes[5]) == 2, "Wrong distance");
Assert.IsTrue(distanceLookup.GetDistance(graphNodes[0], graphNodes[3]) == 3, "Wrong distance");
}
/// <summary>
/// Instantiates a new MinimalSpanningTree.
/// </summary>
/// <param name="mstNodes">The GraphNodes that should be spanned.</param>
/// <param name="distances">An optional DistanceLookup parameter which
/// caches the found node-node distances.</param>
public MinimalSpanningTree(HashSet<GraphNode> mstNodes, DistanceLookup distances = null)
{
// Copy might be preferable, doesn't really matter atm though.
this.mstNodes = mstNodes;
this.distances = (distances == null ? new DistanceLookup() : distances);
_isSpanned = false;
}
public void TestMST()
{
/// 0 -- 1 -- 2 -- 3
/// \ | /
/// \ | /
/// 4 -- 5 -- 6 -- 7
bool[,] graph1 = {
{ false, true, false, false, true, false, false, false },
{ true, false, true, false, false, false, false, false },
{ false, true, false, true, false, true, false, false },
{ false, false, true, false, false, true, false, false },
{ true, false, false, false, false, true, false, false },
{ false, false, true, true, true, false, true, false },
{ false, false, false, false, false, true, false, true },
{ false, false, false, false, false, false, true, false },
};
SearchGraph searchGraph1 = SearchGraphFromData(graph1);
Dictionary<int, GraphNode> graphNodes1 = GetGraphNodesIdIndex(searchGraph1);
DistanceLookup distanceLookup = new DistanceLookup();
HashSet<GraphNode> mstNodes1 = new HashSet<GraphNode>
{ graphNodes1[3], graphNodes1[5], graphNodes1[7] };
MinimalSpanningTree mst1 = new MinimalSpanningTree(mstNodes1);
mst1.Span(startFrom: graphNodes1[0]);
Assert.IsTrue(mst1.SpanningEdges.Count == 3, "Wrong amount of spanning edges");
/// This can fail even if the mst would be valid! The test only works for
/// the current implementation of the mst algorithm, but I can't find a
/// better way to do this with the current data structures...
Assert.IsTrue(mst1.SpanningEdges[0].inside.Id == 0 && mst1.SpanningEdges[0].outside.Id == 5,
"First edge is wrong");
Assert.IsTrue(mst1.SpanningEdges[1].inside.Id == 5 && mst1.SpanningEdges[1].outside.Id == 3,
"Second edge is wrong");
Assert.IsTrue(mst1.SpanningEdges[2].inside.Id == 5 && mst1.SpanningEdges[2].outside.Id == 7,
"Third edge is wrong");
Assert.IsTrue(mst1.UsedNodeCount == 5, "Wrong MST length");
/// Test unconnected graph
/// 0 -- 1 2 -- 3
/// | /
/// | /
/// 4 -- 5
bool[,] graph2 = {
{ false, true, false, false, false, false },
{ true, false, false, false, false, false },
{ false, false, false, true, false, true },
{ false, false, true, false, false, true },
{ false, false, false, false, false, true },
{ false, false, true, true, true, false },
};
SearchGraph searchGraph2 = SearchGraphFromData(graph2);
Dictionary<int, GraphNode> graphNodes2 = GetGraphNodesIdIndex(searchGraph2);
HashSet<GraphNode> mstNodes2 = new HashSet<GraphNode> { graphNodes2[0], graphNodes2[2], graphNodes2[4] };
bool pass = false;
try
{
MinimalSpanningTree mst = new MinimalSpanningTree(mstNodes2);
mst.Span(graphNodes2[3]);
}
catch (DistanceLookup.GraphNotConnectedException)
{
pass = true;
}
Assert.IsTrue(pass, "No exception thrown for disconnected graph");
}
