Changeset 3491 for trunk/sources/HeuristicLab.Problems.DataAnalysis/3.3/Symbolic

Timestamp:

04/22/10 18:41:07 (15 years ago)

Author:

gkronber

Message:

Minor improvements. #938 (Data types and operators for regression problems)

File:

• trunk/sources/HeuristicLab.Problems.DataAnalysis/3.3/Symbolic/SimpleArithmeticExpressionInterpreter.cs (modified) (7 diffs)

trunk/sources/HeuristicLab.Problems.DataAnalysis/3.3/Symbolic/SimpleArithmeticExpressionInterpreter.cs

@@ -33 +33 @@
   [StorableClass]
   [Item("SimpleArithmeticExpressionInterpreter", "Interpreter for arithmetic symbolic expression trees including function calls.")]
+  // not thread safe!
   public class SimpleArithmeticExpressionInterpreter : Item, ISymbolicExpressionTreeInterpreter {
     private class OpCodes {
@@ -45 +46 @@
     }
 
+    private const int ARGUMENT_STACK_SIZE = 1024;
     private Dataset dataset;
     private int row;
@@ -58 +60 @@
         this.row = row;
         pc = 0;
-        argumentStack.Clear();
+        argStackPointer = 0;
         var estimatedValue = Evaluate();
         if (double.IsNaN(estimatedValue) || double.IsInfinity(estimatedValue)) yield return 0.0;
@@ -85 +87 @@
     }
 
-    private Stack<List<double>> argumentStack = new Stack<List<double>>();
+    private double[] argumentStack = new double[ARGUMENT_STACK_SIZE];
+    private int argStackPointer;
+
     public double Evaluate() {
       var currentInstr = code[pc++];
@@ -118 +122 @@
           }
         case OpCodes.Call: {
-            // save current arguments
-            List<double> arguments = new List<double>();
             // evaluate sub-trees
+            // push on argStack in reverse order 
             for (int i = 0; i < currentInstr.nArguments; i++) {
-              arguments.Add(Evaluate());
+              argumentStack[argStackPointer + currentInstr.nArguments - i] = Evaluate();
+              argStackPointer++;
             }
-            argumentStack.Push(arguments);
+
             // save the pc
             int nextPc = pc;
@@ -131 +135 @@
             // evaluate the function
             double v = Evaluate();
-            argumentStack.Pop();
+
+            // decrease the argument stack pointer by the number of arguments pushed
+            // to set the argStackPointer back to the original location
+            argStackPointer -= currentInstr.nArguments;
+
             // restore the pc => evaluation will continue at point after my subtrees  
             pc = nextPc;
@@ -137 +145 @@
           }
         case OpCodes.Arg: {
-            return argumentStack.Peek()[currentInstr.iArg0];
+            return argumentStack[argStackPointer - currentInstr.iArg0];
           }
         case OpCodes.Variable: {