Changeset 15017 for branches/PushGP/HeuristicLab.PushGP/HeuristicLab.Problems.ProgramSynthesis/Push/Simplifier/Simplifier.cs

Timestamp:

06/01/17 09:28:34 (7 years ago)

Author:

pkimmesw

Message:

#2665 Fixed Benchmark Problem Definition, Converted LoopExpressions to stateless expressions, Added several unit test to ensure funcionality, Fixed UI bugs

File:

• branches/PushGP/HeuristicLab.PushGP/HeuristicLab.Problems.ProgramSynthesis/Push/Simplifier/Simplifier.cs (modified) (2 diffs)

branches/PushGP/HeuristicLab.PushGP/HeuristicLab.Problems.ProgramSynthesis/Push/Simplifier/Simplifier.cs

@@ -1 +1 @@
 namespace HeuristicLab.Problems.ProgramSynthesis.Push.Simplifier {
   using System;
-  using System.Collections.Generic;
 
   using Expressions;
 
+  using HeuristicLab.Common;
   using HeuristicLab.Problems.ProgramSynthesis.Push.Configuration;
   using HeuristicLab.Problems.ProgramSynthesis.Push.Data.Tree;
-  using HeuristicLab.Problems.ProgramSynthesis.Push.Interpreter;
 
   public static class Simplifier {
     private static readonly TreeNode<Expression> NoopNode =
-      new TreeNode<Expression>(ExpressionTable.GetStatelessExpression<CodeNoopExpression>());
+      new TreeNode<Expression>(ExpressionTable.GetStatelessExpression<ExecNoopExpression>());
 
-    public static PushProgram Simplify(PushProgram program, IReadOnlyPushConfiguration config, Func<PushProgram, double> evaluator) {
+    public static PushProgram Simplify(PushProgram program, IReadOnlyPushConfiguration config, Func<PushProgram, double> evaluator, bool improveIfPossible = false) {
       var bestResult = evaluator(program);
-      //var noopFreeProgram = RemoveNoops(program, config);
       var tree = program.ToTree();
-      var optimizedTree = RemoveUnnecessaryExpressions(tree, tree, ref bestResult, evaluator);
+      var optimizedTree = RemoveUnnecessaryExpressions(tree, tree, ref bestResult, evaluator, improveIfPossible);
+      var tmp = RemoveUnnecessaryExpressions(optimizedTree, optimizedTree, ref bestResult, evaluator, improveIfPossible);
 
-      var optimizedPrgram = optimizedTree.ToPushProgram(e => !ReferenceEquals(e, NoopNode.Value));
-      return optimizedPrgram; // RemoveNoops(optimizedPrgram, config);
+      while (tmp.Count < optimizedTree.Count) {
+        optimizedTree = tmp;
+      }
+
+      var optimizedProgram = optimizedTree.ToPushProgramWithoutNoopExpressions();
+      optimizedProgram = SimplifySubPrograms(optimizedProgram);
+
+      return optimizedProgram;
     }
 
-    // not working so far, an expression can only be a noop if it is a noop for all examples of a problem
-    private static PushProgram RemoveNoops(PushProgram pushProgram, IReadOnlyPushConfiguration config) {
-      var expressions = new List<Expression>();
-      var interpreter = new PushInterpreter(config);
+    public static PushProgram SimplifySubPrograms(PushProgram program) {
+      var tree = program.ToTree();
+      var optimizedTree = SimplifySubPrograms(tree);
+      var optimizedPrgram = optimizedTree.ToPushProgram();
 
-      interpreter.Run(pushProgram, true);
+      return optimizedPrgram;
+    }
 
-      while (interpreter.CanStep) {
-        var isNoop = interpreter.ExecStack.Top.IsNoop(interpreter);
-        if (!isNoop)
-          expressions.Add(interpreter.ExecStack.Top);
+    private static TreeNode<Expression> SimplifySubPrograms(TreeNode<Expression> program) {
+      while (program.Children.Count == 1)
+        program = program.Children[0];
 
-        interpreter.Step();
+      for (var i = 0; i < program.Children.Count; i++) {
+        var child = program.Children[i];
+        program.ReplaceNode(i, SimplifySubPrograms(child));
       }
 
-      return new PushProgram(expressions);
+      return program;
     }
 
-    private static TreeNode<Expression> RemoveUnnecessaryExpressions(Tree<Expression> program, TreeNode<Expression> node, ref double bestResult, Func<PushProgram, double> evaluator) {
+    private static TreeNode<Expression> RemoveUnnecessaryExpressions(TreeNode<Expression> program, TreeNode<Expression> node, ref double bestResult, Func<PushProgram, double> evaluator, bool improveIfPossible = false) {
       for (var i = 0; i < node.Children.Count; i++) {
         var child = node.Children[i];
@@ -49 +56 @@
         var currentResult = evaluator(currentProgram);
 
-        if (currentResult <= bestResult) {
+        if ((improveIfPossible && currentResult <= bestResult) ||
+            (!improveIfPossible && currentResult.IsAlmost(bestResult))) {
           bestResult = currentResult;
         } else if (child.Value.IsProgram) {