Changeset 11799 for branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Problems.GrammaticalOptimization/RoyalSequenceProblem.cs

Timestamp:

01/19/15 20:09:12 (9 years ago)

Author:

gkronber

Message:

#2283: performance tuning and reactivated random-roll-out policy in sequential search

File:

• branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Problems.GrammaticalOptimization/RoyalSequenceProblem.cs (modified) (4 diffs)

branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Problems.GrammaticalOptimization/RoyalSequenceProblem.cs

@@ -31 +31 @@
       this.correctReward = correctReward;
       this.incorrectReward = incorrectReward;
-      var sentenceSymbol = 'S';
+      const char sentenceSymbol = 'S';
       var terminalSymbols = Enumerable.Range(0, alphabetSize).Select(off => (char)((byte)'a' + off)).ToArray();
-      var nonTerminalSymbols = new char[] { 'S' };
-      var rules = terminalSymbols.Select(t => Tuple.Create('S', t.ToString()))
-        .Concat(terminalSymbols.Select(t => Tuple.Create('S', t + "S")));
+      var nonTerminalSymbols = new char[] { sentenceSymbol };
+      var rules = terminalSymbols.Select(t => Tuple.Create(sentenceSymbol, t.ToString()))
+        .Concat(terminalSymbols.Select(t => Tuple.Create(sentenceSymbol, t + sentenceSymbol.ToString())));
       //var rules = terminalSymbols.Select(t => Tuple.Create('S', t + "S"))
       //  .Concat(terminalSymbols.Select(t => Tuple.Create('S', t.ToString())));
@@ -64 +64 @@
       // sentence must contain only terminal symbols, we are not checking if the sentence is syntactically valid here because it would be too slow!
       Debug.Assert(sentence.Any(c => grammar.IsTerminal(c)));
-      // as long as only correct symbols are found we increase the reward by +1
-      // on the first incorrect symbol we return
       var reward = 0.0;
       for (int i = 0; i < Math.Min(sentence.Length, sequenceLen); i++) {
@@ -71 +69 @@
           reward += correctReward;
         } else {
-          // alternatively reduce reward by number of remaining symbols
+          //  reduce reward by number of remaining symbols
           return Math.Max(0.0, reward + incorrectReward * (sentence.Length - i));
-          // stop on first incorrect symbol and return reward
-          //return reward;
         }
       }
@@ -80 +76 @@
     }
 
+    // in each position there could be multiple correct and incorrect symbols
     public string CanonicalRepresentation(string terminalPhrase) {
-      throw new NotImplementedException();
-      return terminalPhrase;
+      var sb = new StringBuilder();
+      for (int i = 0; i < terminalPhrase.Length; i++) {
+        if (optimalSymbolsForPos[i].Contains(terminalPhrase[i])) {
+          sb.Append(optimalSymbolsForPos[i].First()); // all symbols in the set are equivalent
+        } else {
+          sb.Append(terminalPhrase[i]);
+        }
+      }
+      return sb.ToString();
     }
   }