public static void mutateOpportunistic(GeneticTree current)
{
NodeStatistics stats = current.allNodesStats(current._root, 0, "", 0);
List <NodeStatsPair> opportunities = new List <NodeStatsPair>();
foreach (var item in current._nodeStatsDictionary)
{
//Debug.WriteLine("Node " + item.Key + " /// Operator variance: " + item.Value._opVariance + " Variable variance: " + item.Value._varVariance + " Avg depth: " + item.Value._avgDepth + " Avg branching: " + item.Value._avgBranching);
opportunities.Add(new NodeStatsPair(item.Key, item.Value._avgBranching + item.Value._avgDepth + item.Value._opVariance + item.Value._varVariance));
}
float max = opportunities.Max(x => x._mutationValue);
foreach (var item in opportunities)
{
item._mutationValue = max - item._mutationValue + 1; // make less branchy, depthy and variant more likely to be mutated
}
opportunities = opportunities.OrderByDescending(x => x._mutationValue).ToList();
float[] wSum = new float[opportunities.Count];
wSum[0] = opportunities[0]._mutationValue;
for (int i = 1; i < wSum.Length; i++)
{
wSum[i] = opportunities[i]._mutationValue + wSum[i - 1];
}
float sumF = opportunities.Sum(x => x._mutationValue);
double centil = Rng.Rnd.NextDouble() * sumF;
int index = 0;
for (int i = 0; i < opportunities.Count && centil < wSum[i]; i++)
{
index = i;
}
string currentIndex = opportunities[index]._node;
int newDepth = (int)current._maxDepth - currentIndex.Length + 1;
GeneticTree added = new GeneticTree((uint)newDepth, current._maxBranching);
GeneticNode tmp = current._root;
for (int i = 1; i < currentIndex.Length; i++) // traversing to find proper index
{
index = GeneticTree._TREE_NODES_CHAR_TO_INT[currentIndex[i]];
tmp = tmp._children._children[index];
}
current.attachNode(added._root, currentIndex);
current.recalculateIndices();
}
public NodeStatistics allNodesStats(GeneticNode current, int currentDepth, string previousTag, int childOrdinal)
{
string currentTag = previousTag + _TREE_NODES_INT_TO_CHAR[childOrdinal];
NodeStatistics ns = new NodeStatistics();
ns._totalCount++;
ns._depth += currentDepth;
switch (current)
{
case OperatorNode on:
ns._totalOpCount++;
ns._branching += (int)current._childNum;
ns._opCount[(int)on._operatorType]++;
for (int i = 0; i < on._childNum; i++)
{
NodeStatistics res = allNodesStats(on._children[i], currentDepth + 1, currentTag, i);
ns._branching += res._branching;
ns._depth += res._depth;
ns._totalCount += res._totalCount;
ns._totalOpCount += res._totalOpCount;
ns._opCount = res._opCount.Zip(ns._opCount, (x, y) => x + y).ToArray();
ns._varCount = res._varCount.Zip(ns._varCount, (x, y) => x + y).ToArray();
}
break;
case VariableNode vn:
ns._varCount[(int)vn._variableType]++;
break;
case MultipleNode mn:
ns._totalOpCount++;
ns._opCount[OPERATOR_NODES_NUM + MULTIPLE_NODES_NUM - 1]++;
ns._branching += (int)current._childNum;
for (int i = 0; i < mn._childNum; i++)
{
NodeStatistics res = allNodesStats(mn._children[i], currentDepth + 1, currentTag, i);
ns._branching += res._branching;
ns._totalCount += res._totalCount;
ns._totalOpCount += res._totalOpCount;
ns._depth += res._depth;
ns._opCount = res._opCount.Zip(ns._opCount, (x, y) => x + y).ToArray();
ns._varCount = res._varCount.Zip(ns._varCount, (x, y) => x + y).ToArray();
}
break;
default: // ConstNode
ns._varCount[GeneticTree.VARIABLE_NODES_NUM + GeneticTree.CONST_NODES_NUM - 1]++;
break;
}
if (currentDepth < _maxDepth)
{
if (ns._branching == 0 || ns._totalOpCount == 0)
{
ns._avgBranching = 1;
}
else
{
ns._avgBranching = ns._branching / (float)ns._totalOpCount;
}
ns._avgDepth = (float)ns._depth / (float)ns._totalCount;
ns._avgDepth -= currentDepth;
double opAvg = ns._opCount.Average();
double varAvg = ns._varCount.Average();
double accOp = 0, accVar = 0;
accOp = ns._opCount.Aggregate(0.0, (acc, val) => (double)(acc + ((val - opAvg) * (val - opAvg))));
accVar = ns._varCount.Aggregate(0.0, (acc, val) => (double)(acc + ((val - varAvg) * (val - varAvg))));
ns._opVariance = (float)accOp / ns._opCount.Length;
ns._varVariance = (float)accVar / ns._varCount.Length;
_nodeStatsDictionary[currentTag] = ns;
}
return(ns);
}
