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Fixed a bug with Dijkstra's solver with multiple destinations in a network.
1 parent 3d40102 commit d7a8039

3 files changed

Lines changed: 703 additions & 87 deletions

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‎4.8.1/Numerics/Mathematics/Optimization/Dynamic/Dijkstra.cs‎

Lines changed: 104 additions & 87 deletions
Original file line numberDiff line numberDiff line change
@@ -36,95 +36,112 @@
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namespace Numerics.Mathematics.Optimization
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{
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public struct Edge
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/// <summary>
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/// Struct that represents an edge in a network.
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/// </summary>
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/// <remarks>
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/// Create an edge structure object. An edge contains information on the start node, end node, edge weight, and edge index.
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/// </remarks>
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/// <param name="fromNodeIndex">Node index at start of edge.</param>
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/// <param name="toNodeIndex">Node index at end of edge.</param>
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/// <param name="edgeWeight">Weight (or Cost) of the edge.</param>
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/// <param name="edgeIndex">Index of the edge.</param>
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public struct Edge(int fromNodeIndex, int toNodeIndex, float edgeWeight, int edgeIndex)
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{
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public int FromIndex;
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public int ToIndex;
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public float Weight;
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public int Index;
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public Edge(int fromNodeIndex, int toNodeIndex, float edgeWeight, int edgeIndex)
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{
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FromIndex = fromNodeIndex;
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ToIndex = toNodeIndex;
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Weight = edgeWeight;
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Index = edgeIndex;
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}
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}
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public class Networks
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{
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private readonly List<Edge>[] _outgoingEdges;
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private readonly List<Edge>[] _incomingEdges;
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private readonly int _nodeCount;
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private readonly int[] _destinationIndices;
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//private readonly RoadSegment[] _segments;
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private readonly Edge[] _edges;
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//public RoadSegment[] Segments { get => _segments; }
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public int[] DestinationIndices { get => _destinationIndices; }
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public List<Edge>[] IncomingEdges { get => _incomingEdges; }
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public List<Edge>[] OutgoingEdges { get => _outgoingEdges; }
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public static void ResultsToCSV(float[,] result, string outputFilePath)
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{
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System.IO.StreamWriter sw = new System.IO.StreamWriter(outputFilePath);
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//Headers
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sw.WriteLine($"From_Node, To_Node, Edge, Weight_To_Destination");
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//Data
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for (Int32 i = 0; i < result.GetLength(0); i++) { sw.WriteLine($"{i}, {result[i, 0]}, {result[i, 1]}, {result[i, 2]}"); }
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sw.Close(); sw.Dispose();
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}
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public static int[] PathEdges(float[,] result, int startNodeIndex)
80-
{
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List<int> edgeList = new List<int>();
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int nodeIndex = startNodeIndex;
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// generate the shortest path list from the results table
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while (result[nodeIndex, 2] != 0)
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{
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edgeList.Add((int)result[nodeIndex, 1]);
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nodeIndex = (int)result[nodeIndex, 0];
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}
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return edgeList.ToArray();
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}
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//public int[] PathRecords(float[,] result, int startNodeIndex)
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//{
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// List<int> featureList = new List<int>();
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// int nodeIndex = startNodeIndex;
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// // generate the shortest path list from the results table
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// while (result[nodeIndex, 2] != 0)
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// {
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// featureList.Add(_segments[(int)result[nodeIndex, 1]].RecordIndex);
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// nodeIndex = (int)result[nodeIndex, 0];
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// }
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// return featureList.ToArray();
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//}
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//public int[] PathRecords(float[,] result, int startRecordIndex)
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//{
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// List<int> featureList = new List<int>();
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// for (int i = 0; i < result.GetLength(0); i++)
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// {
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// if (_segments[(int)result[i, 1]].RecordIndex == startRecordIndex)
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// {
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// int nodeIndex = i;
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// // generate the shortest path list from the results table
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// while (result[nodeIndex, 2] != 0)
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// {
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// featureList.Add(_segments[(int)result[nodeIndex, 1]].RecordIndex);
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// nodeIndex = (int)result[nodeIndex, 0];
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// }
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// break;
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// }
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// }
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// return featureList.ToArray();
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//}
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/// <summary>
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/// Node index at start of edge.
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/// </summary>
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public int FromIndex = fromNodeIndex;
55+
/// <summary>
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/// Node index at end of edge.
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/// </summary>
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public int ToIndex = toNodeIndex;
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/// <summary>
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/// Weight (or Cost) of transversing the edge.
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/// </summary>
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public float Weight = edgeWeight;
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/// <summary>
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/// Index of the edge, often used as an index to the edge source (e.g., road segment).
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/// </summary>
66+
public int Index = edgeIndex;
12567
}
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127-
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//public class Networks
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//{
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// private readonly List<Edge>[] _outgoingEdges;
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// private readonly List<Edge>[] _incomingEdges;
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// private readonly int _nodeCount;
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// private readonly int[] _destinationIndices;
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// //private readonly RoadSegment[] _segments;
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// private readonly Edge[] _edges;
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// //public RoadSegment[] Segments { get => _segments; }
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// public int[] DestinationIndices { get => _destinationIndices; }
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// public List<Edge>[] IncomingEdges { get => _incomingEdges; }
81+
// public List<Edge>[] OutgoingEdges { get => _outgoingEdges; }
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83+
// public static void ResultsToCSV(float[,] result, string outputFilePath)
84+
// {
85+
// System.IO.StreamWriter sw = new System.IO.StreamWriter(outputFilePath);
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// //Headers
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// sw.WriteLine($"From_Node, To_Node, Edge, Weight_To_Destination");
88+
// //Data
89+
// for (int i = 0; i < result.GetLength(0); i++) { sw.WriteLine($"{i}, {result[i, 0]}, {result[i, 1]}, {result[i, 2]}"); }
90+
// sw.Close(); sw.Dispose();
91+
// }
92+
93+
// public static int[] PathEdges(float[,] result, int startNodeIndex)
94+
// {
95+
// List<int> edgeList = new List<int>();
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// int nodeIndex = startNodeIndex;
97+
// // generate the shortest path list from the results table
98+
// while (result[nodeIndex, 2] != 0)
99+
// {
100+
// edgeList.Add((int)result[nodeIndex, 1]);
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// nodeIndex = (int)result[nodeIndex, 0];
102+
// }
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// return edgeList.ToArray();
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// }
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// //public int[] PathRecords(float[,] result, int startNodeIndex)
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// //{
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// // List<int> featureList = new List<int>();
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// // int nodeIndex = startNodeIndex;
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// // // generate the shortest path list from the results table
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// // while (result[nodeIndex, 2] != 0)
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// // {
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// // featureList.Add(_segments[(int)result[nodeIndex, 1]].RecordIndex);
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// // nodeIndex = (int)result[nodeIndex, 0];
115+
// // }
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// // return featureList.ToArray();
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// //}
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119+
// //public int[] PathRecords(float[,] result, int startRecordIndex)
120+
// //{
121+
// // List<int> featureList = new List<int>();
122+
// // for (int i = 0; i < result.GetLength(0); i++)
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// // {
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// // if (_segments[(int)result[i, 1]].RecordIndex == startRecordIndex)
125+
// // {
126+
// // int nodeIndex = i;
127+
// // // generate the shortest path list from the results table
128+
// // while (result[nodeIndex, 2] != 0)
129+
// // {
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// // featureList.Add(_segments[(int)result[nodeIndex, 1]].RecordIndex);
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// // nodeIndex = (int)result[nodeIndex, 0];
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// // }
133+
// // break;
134+
// // }
135+
// // }
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137+
// // return featureList.ToArray();
138+
// //}
139+
//}
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141+
142+
/// <summary>
143+
/// Dijkstra dynamic programming implementation for shortest path optimization.
144+
/// </summary>
128145
public static class Dijkstra
129146
{
130147
/// <summary>
@@ -255,7 +272,7 @@ public static class Dijkstra
255272
resultTable[destinationIndex, 0] = destinationIndex; //Tail
256273
resultTable[destinationIndex, 1] = -1; //edge index
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resultTable[destinationIndex, 2] = 0; //Cumulative Weight
258-
275+
previousValue = destinationIndex;
259276
if (edgesToNodes[previousValue] == null) { continue; }
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//Add the nodes to the heap connected to the given destination node.

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