Changeset 15553 for branches/GeneralizedQAP/HeuristicLab.Problems.GeneralizedQuadraticAssignment/3.3/SolutionCreators

Timestamp:

12/20/17 15:41:27 (7 years ago)

Author:

abeham

Message:

#1614:

• Implementing basic algorithm according to paper (rechecking all operators)
• Checking implementation with paper
• Improved speed of move generator
• Improved speed of randomized solution creator

File:

• branches/GeneralizedQAP/HeuristicLab.Problems.GeneralizedQuadraticAssignment/3.3/SolutionCreators/GreedyRandomizedSolutionCreator.cs (modified) (5 diffs)

branches/GeneralizedQAP/HeuristicLab.Problems.GeneralizedQuadraticAssignment/3.3/SolutionCreators/GreedyRandomizedSolutionCreator.cs

@@ -61 +61 @@
       int maximumTries, bool createMostFeasibleSolution, CancellationToken cancelToken) {
       var demands = problemInstance.Demands;
-      var capacities = problemInstance.Capacities;
+      var capacities = problemInstance.Capacities.ToArray();
+      var equipments = demands.Length;
+      var locations = capacities.Length;
       int tries = 0;
-      var assignment = new Dictionary<int, int>(demands.Length);
-      DoubleArray slack = new DoubleArray(capacities.Length);
+      var assignment = new int[equipments];
+      var slack = new double[locations];
       double minViolation = double.MaxValue;
-      Dictionary<int, int> bestAssignment = null;
-      HashSet<int> CF = new HashSet<int>(), // set of chosen facilities / equipments
-          T = new HashSet<int>(), // set of facilities / equpiments that can be assigned to the set of chosen locations (CL)
-          CL = new HashSet<int>(), // set of chosen locations
-          F = new HashSet<int>(Enumerable.Range(0, demands.Length)), // set of (initially) all facilities / equipments
-          L = new HashSet<int>(Enumerable.Range(0, capacities.Length)); // set of (initially) all locations
-
+      int[] bestAssignment = null;
+      var CF = new bool[equipments]; // set of chosen facilities / equipments
+      var T = new List<int>(equipments); // set of facilities / equpiments that can be assigned to the set of chosen locations (CL)
+      var CL_list = new List<int>(locations); // list of chosen locations
+      var CL_selected = new bool[locations]; // bool decision if location is chosen
+      var F = new List<int>(equipments); // set of (initially) all facilities / equipments
+      var L = new List<int>(locations); // set of (initially) all locations
+      
       while (maximumTries <= 0 || tries < maximumTries) {
         cancelToken.ThrowIfCancellationRequested();
 
-        assignment.Clear();
-        for (int i = 0; i < capacities.Length; i++) slack[i] = capacities[i];
-        CF.Clear();
+        Array.Copy(capacities, slack, locations);
+        Array.Clear(CF, 0, equipments);
+        Array.Clear(CL_selected, 0, locations);
+        CL_list.Clear();
         T.Clear();
-        CL.Clear();
-        F.Clear(); F.UnionWith(Enumerable.Range(0, demands.Length));
-        L.Clear(); L.UnionWith(Enumerable.Range(0, capacities.Length));
+
+        F.Clear(); F.AddRange(Enumerable.Range(0, equipments));
+        L.Clear(); L.AddRange(Enumerable.Range(0, locations));
 
         double threshold = 1.0;
         do {
-          if (L.Any() && random.NextDouble() < threshold) {
+          if (L.Count > 0 && random.NextDouble() < threshold) {
             int l = L.SampleRandom(random);
             L.Remove(l);
-            CL.Add(l);
-            T = new HashSet<int>(WithDemandEqualOrLess(F, GetMaximumSlack(slack, CL), demands));
+            CL_list.Add(l);
+            CL_selected[l] = true;
+            T = new List<int>(WhereDemandEqualOrLess(F, GetMaximumSlack(slack, CL_selected), demands));
           }
-          if (T.Any()) {
-            int f = T.SampleRandom(random);
-            T.Remove(f);
-            F.Remove(f);
-            CF.Add(f);
-            int l = WithSlackGreaterOrEqual(CL, demands[f], slack).SampleRandom(random);
-            assignment.Add(f, l);
+          if (T.Count > 0) {
+            var fidx = Enumerable.Range(0, T.Count).SampleRandom(random);
+            var f = T[fidx];
+            T.RemoveAt(fidx);
+            F.Remove(f); // TODO: slow
+            CF[f] = true;
+            int l = WhereSlackGreaterOrEqual(CL_list, demands[f], slack).SampleRandom(random);
+            assignment[f] = l + 1;
             slack[l] -= demands[f];
-            T = new HashSet<int>(WithDemandEqualOrLess(F, GetMaximumSlack(slack, CL), demands));
+            T = new List<int>(WhereDemandEqualOrLess(F, GetMaximumSlack(slack, CL_selected), demands));
             threshold = 1.0 - (double)T.Count / Math.Max(F.Count, 1.0);
           }
-        } while (T.Any() || L.Any());
+        } while (T.Count > 0 || L.Count > 0);
         if (maximumTries > 0) tries++;
-        if (!F.Any()) {
+        if (F.Count == 0) {
           bestAssignment = assignment;
           break;
@@ -111 +117 @@
           // complete the solution and remember the one with least violation
           foreach (var l in L.ToArray()) {
-            CL.Add(l);
+            CL_list.Add(l);
+            CL_selected[l] = true;
             L.Remove(l);
           }
-          while (F.Any()) {
-            var f = F.MaxItems(x => demands[x]).SampleRandom(random);
-            var l = CL.MaxItems(x => slack[x]).SampleRandom(random);
-            F.Remove(f);
-            assignment.Add(f, l);
-            slack[l] -= demands[f];
+          while (F.Count > 0) {
+            var f = F.Select((v, i) => new { Index = i, Value = v }).MaxItems(x => demands[x.Value]).SampleRandom(random);
+            var l = CL_list.MaxItems(x => slack[x]).SampleRandom(random);
+            F.RemoveAt(f.Index);
+            assignment[f.Value] = l + 1;
+            slack[l] -= demands[f.Value];
           }
           double violation = slack.Select(x => x < 0 ? -x : 0).Sum();
           if (violation < minViolation) {
             bestAssignment = assignment;
-            assignment = new Dictionary<int, int>(demands.Length);
+            assignment = new int[equipments];
             minViolation = violation;
           }
@@ -130 +137 @@
       }
 
-      if (bestAssignment == null || bestAssignment.Count != demands.Length) throw new InvalidOperationException(String.Format("No solution could be found in {0} tries.", maximumTries));
+      if (bestAssignment == null || bestAssignment.Any(x => x == 0))
+        throw new InvalidOperationException(String.Format("No solution could be found in {0} tries.", maximumTries));
 
-      return new IntegerVector(bestAssignment.OrderBy(x => x.Key).Select(x => x.Value).ToArray());
+      return new IntegerVector(bestAssignment.Select(x => x - 1).ToArray());
     }
 
@@ -142 +150 @@
     }
 
-    private static IEnumerable<int> WithDemandEqualOrLess(IEnumerable<int> facilities, double maximum, DoubleArray demands) {
+    private static IEnumerable<int> WhereDemandEqualOrLess(IEnumerable<int> facilities, double maximum, DoubleArray demands) {
       foreach (int f in facilities) {
         if (demands[f] <= maximum) yield return f;
@@ -148 +156 @@
     }
 
-    private static double GetMaximumSlack(DoubleArray slack, HashSet<int> CL) {
-      return slack.Select((val, idx) => new { idx, val }).Where(x => CL.Contains(x.idx)).Select(x => x.val).Max();
+    private static double GetMaximumSlack(double[] slack, bool[] CL) {
+      var max = double.MinValue;
+      for (var i = 0; i < slack.Length; i++) {
+        if (CL[i] && max < slack[i]) max = slack[i];
+      }
+      return max;
     }
 
-    private static IEnumerable<int> WithSlackGreaterOrEqual(HashSet<int> locations, double minimum, DoubleArray slack) {
+    private static IEnumerable<int> WhereSlackGreaterOrEqual(IEnumerable<int> locations, double minimum, double[] slack) {
       foreach (int l in locations) {
         if (slack[l] >= minimum) yield return l;