Changeset 10788

Timestamp:

04/24/14 09:23:18 (11 years ago)

Author:

mkommend

Message:

#2177: Corrected evaluation of the xor symbol in the interpreters.

Location:

trunk/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Interpreter

Files:

• SymbolicDataAnalysisExpressionTreeInterpreter.cs (modified) (1 diff)
• SymbolicDataAnalysisExpressionTreeLinearInterpreter.cs (modified) (1 diff)

trunk/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Interpreter/SymbolicDataAnalysisExpressionTreeInterpreter.cs

@@ -345 +345 @@
           }
         case OpCodes.XOR: {
-            double firstArgument = Evaluate(dataset, ref row, state);
-            double result = 1.0;
-            for (int i = 1; i < currentInstr.nArguments; i++) {
-              if (result <= 0.0) {
-                state.SkipInstructions();
-              } else {
-                double evalutationResult = Evaluate(dataset, ref row, state);
-                if (firstArgument <= 0 && evalutationResult > 0) result = -1.0;
-                else if (firstArgument > 0 && evalutationResult <= 0) result = -1.0;
-              }
-            }
-            return result > 0.0 ? 1.0 : -1.0;
+            //mkommend: XOR on multiple inputs is defined as true if the number of positive signals is odd
+            // this is equal to a consecutive execution of binary XOR operations.
+            int positiveSignals = 0;
+            for (int i = 0; i < currentInstr.nArguments; i++) {
+              if (Evaluate(dataset, ref row, state) > 0.0) positiveSignals++;
+            }
+            return positiveSignals % 2 != 0 ? 1.0 : -1.0;
           }
         case OpCodes.GT: {

trunk/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Interpreter/SymbolicDataAnalysisExpressionTreeLinearInterpreter.cs

@@ -312 +312 @@
           instr.value = code[instr.childIndex].value > 0.0 ? -1.0 : 1.0;
         } else if (instr.opCode == OpCodes.XOR) {
-          double firstArgument = code[instr.childIndex].value;
-          instr.value = 1.0;
-          for (int j = 1; j < instr.nArguments; j++) {
-            if (instr.value > 0.0) {
-              if (firstArgument <= 0 && code[instr.childIndex + j].value > 0) instr.value = -1.0;
-              if (firstArgument > 0 && code[instr.childIndex + j].value <= 0) instr.value = -1.0;
-            } else break;
-          }
-          instr.value = instr.value > 0.0 ? 1.0 : -1.0;
+          int positiveSignals = 0;
+          for (int j = 0; j < instr.nArguments; j++) {
+            if (code[instr.childIndex + j].value > 0.0) positiveSignals++;
+          }
+          instr.value = positiveSignals % 2 != 0 ? 1.0 : -1.0;
         } else if (instr.opCode == OpCodes.GT) {
           double x = code[instr.childIndex].value;