Changeset 16305 for trunk

Timestamp:

11/19/18 15:30:44 (5 years ago)

Author:

bburlacu

Message:

#2950: Change Simplify inside HashNode to a delegate (instead of an Action) so that the nodes array can be passed as ref. This enables us to resize/alter the nodes array during simplification (eg, by performing term expansion or similar operations)

Location:

trunk/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Hashing

Files:

• HashExtensions.cs (modified) (2 diffs)
• SymbolicExpressionTreeHash.cs (modified) (6 diffs)

trunk/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Hashing/HashExtensions.cs

@@ -35 +35 @@
       public ulong CalculatedHashValue; // the calculated hash value (taking into account the children hash values)
 
-      public Action<HashNode<T>[], int> Simplify;
+      public delegate void SimplifyAction(ref HashNode<T>[] nodes, int i);
+      public SimplifyAction Simplify;
+
       public IComparer<T> Comparer;
 
@@ -108 +110 @@
           continue;
         }
-        node.Simplify?.Invoke(reduced, i);
+        node.Simplify?.Invoke(ref reduced, i);
       }
       // detect if anything was simplified

trunk/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Hashing/SymbolicExpressionTreeHash.cs

@@ -227 +227 @@
     }
 
-    public static void SimplifyAddition(HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
+    public static void SimplifyAddition(ref HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
       // simplify additions of terms by eliminating terms with the same symbol and hash
       var children = nodes.IterateChildren(i);
 
+      // we always assume the child nodes are sorted
       var curr = children[0];
       var node = nodes[i];
@@ -236 +237 @@
       foreach (var j in children.Skip(1)) {
         if (nodes[j] == nodes[curr]) {
-          for (int k = j - nodes[j].Size; k <= j; ++k) {
-            nodes[k].Enabled = false;
-          }
+          nodes.SetEnabled(j, false);
           node.Arity--;
         } else {
@@ -250 +249 @@
 
     // simplify multiplications by reducing constants and div terms  
-    public static void SimplifyMultiplication(HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
+    public static void SimplifyMultiplication(ref HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
       var node = nodes[i];
       var children = nodes.IterateChildren(i);
@@ -298 +297 @@
     }
 
-    public static void SimplifyDivision(HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
+    public static void SimplifyDivision(ref HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
       var node = nodes[i];
       var children = nodes.IterateChildren(i);
 
-      if (children.All(x => nodes[x].Data.Symbol is Constant)) {
+      var tmp = nodes;
+
+      if (children.All(x => tmp[x].Data.Symbol is Constant)) {
         var v = ((ConstantTreeNode)nodes[children.First()].Data).Value;
         if (node.Arity == 1) {
@@ -333 +334 @@
     }
 
-    public static void SimplifyUnaryNode(HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
+    public static void SimplifyUnaryNode(ref HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
       // check if the child of the unary node is a constant, then the whole node can be simplified
       var parent = nodes[i];
@@ -348 +349 @@
     }
 
-    public static void SimplifyBinaryNode(HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
+    public static void SimplifyBinaryNode(ref HashNode<ISymbolicExpressionTreeNode>[] nodes, int i) {
       var children = nodes.IterateChildren(i);
-      if (children.All(x => nodes[x].Data.Symbol is Constant)) {
+      var tmp = nodes;
+      if (children.All(x => tmp[x].Data.Symbol is Constant)) {
         foreach (var j in children) {
           nodes[j].Enabled = false;