Changeset 11730 for branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Algorithms.GrammaticalOptimization/AlternativesSampler.cs

Timestamp:

01/02/15 16:08:21 (9 years ago)

Author:

gkronber

Message:

#2283: several major extensions for grammatical optimization

File:

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

branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Algorithms.GrammaticalOptimization/AlternativesSampler.cs

@@ -27 +27 @@
       InitPolicies(problem.Grammar);
       for (int i = 0; i < maxIterations; i++) {
-        var sentence = SampleSentence(problem.Grammar);
-        var quality = problem.Evaluate(sentence) / problem.GetBestKnownQuality(maxLen); 
+        var sentence = SampleSentence(problem.Grammar).ToString();
+        var quality = problem.Evaluate(sentence) / problem.GetBestKnownQuality(maxLen);
         DistributeReward(quality);
 
@@ -52 +52 @@
     }
 
-    private string SampleSentence(IGrammar grammar) {
+    private Sequence SampleSentence(IGrammar grammar) {
       updateChain.Clear();
-      return CompleteSentence(grammar, grammar.SentenceSymbol.ToString());
+      return CompleteSentence(grammar, new Sequence(grammar.SentenceSymbol));
     }
 
-    public string CompleteSentence(IGrammar g, string phrase) {
+    public Sequence CompleteSentence(IGrammar g, Sequence phrase) {
       if (phrase.Length > maxLen) throw new ArgumentException();
       if (g.MinPhraseLength(phrase) > maxLen) throw new ArgumentException();
-      bool done = phrase.All(g.IsTerminal); // terminal phrase means we are done
+      bool done = phrase.IsTerminal; // terminal phrase means we are done
       while (!done) {
-        int ntIdx; char nt;
-        Grammar.FindFirstNonTerminal(g, phrase, out nt, out ntIdx);
+        char nt = phrase.FirstNonTerminal;
 
         int maxLenOfReplacement = maxLen - (phrase.Length - 1); // replacing aAb with maxLen 4 means we can only use alternatives with a minPhraseLen <= 2
@@ -69 +68 @@
 
         var alts = g.GetAlternatives(nt);
-        string selectedAlt;
+        Sequence selectedAlt;
         // if the choice is restricted then one of the allowed alternatives is selected randomly
         if (alts.Any(alt => g.MinPhraseLength(alt) > maxLenOfReplacement)) {
@@ -84 +83 @@
 
         // replace nt with alt
-        phrase = phrase.Remove(ntIdx, 1);
-        phrase = phrase.Insert(ntIdx, selectedAlt);
+        phrase.ReplaceAt(phrase.FirstNonTerminalIndex, 1, selectedAlt);
 
-        done = phrase.All(g.IsTerminal); // terminal phrase means we are done
+        done = phrase.IsTerminal; // terminal phrase means we are done
       }
       return phrase;