public void CreateChildrenOnItemId(int itemId, AttributeValues attributeValues)
{
if (double.IsNaN(Entropy) || Entropy < 0.0001)
{
//System.Console.WriteLine("Will not create children. Entropy of {0} is below threshold.", Entropy);
return;
}
Attribute bestAttribute;
object bestAttributeValue;
SplitAttributeInformationGain = Sources.FindGreatestInformationGain(itemId, attributeValues,
out bestAttribute, out bestAttributeValue);
SplitAttribute = bestAttribute;
SplitAttributeValue = bestAttributeValue;
//if (SplitAttributeInformationGain < Entropy / 100)
if (SplitAttributeInformationGain < Entropy / 10000000)
{
//System.Console.WriteLine("Will not create children. Information gain of {0} is below threshold.",
// SplitAttributeInformationGain);
return;
}
Dictionary <object, DataSourcesCollection> splits;
Sources.DivideOnAttribute(bestAttribute, bestAttributeValue, attributeValues.ValuesMap[bestAttribute],
out splits);
Parallel.ForEach(splits, split =>
{
split.Value.UseAttributesWithValues = Sources.UseAttributesWithValues;
DecisionTreeNode child = new DecisionTreeNode
{
Sources = split.Value,
ItemId = itemId,
ParentSplitAttribute = SplitAttribute,
ParentSplitAttributeValue = split.Key,
};
lock (Children)
{
Children.Add(split.Key, child);
}
child.CreateChildrenOnItemId(itemId, attributeValues);
});
}
public double FindGreatestInformationGain(int itemId, AttributeValues attributeValues,
out Attribute bestAttribute, out object bestAttributeValue)
{
double bestInformationGain = double.MinValue;
Attribute bestAttributeLocal = Attribute.Build;
object bestAttributeValueLocal = null;
Parallel.ForEach(Enum.GetValues(typeof(LootGainLib.Attribute)).Cast <LootGainLib.Attribute>(), attribute =>
{
switch (attribute)
{
case LootGainLib.Attribute.Quest:
if (!UseAttributesWithValues)
{
break;
}
Parallel.ForEach(attributeValues.ValuesMap[LootGainLib.Attribute.Quest].Keys, quest =>
{
var questInformationGain = this.InformationGainOnItemId(itemId, attribute, quest,
attributeValues.ValuesMap[attribute]);
if (questInformationGain > bestInformationGain)
{
lock (lockObject)
{
if (questInformationGain > bestInformationGain)
{
bestInformationGain = questInformationGain;
bestAttributeLocal = attribute;
bestAttributeValueLocal = quest;
System.Console.WriteLine("New best information gain: Quest {0} at {1}",
quest, questInformationGain);
}
}
}
//System.Console.WriteLine("Information gain on quest {0}: {1}", quest,
// questInformationGain);
});
break;
case LootGainLib.Attribute.Loot:
break;
default:
var loopInformationGain = this.InformationGainOnItemId(itemId, attribute, null,
attributeValues.ValuesMap[attribute]);
if (loopInformationGain > bestInformationGain)
{
lock (lockObject)
{
if (loopInformationGain > bestInformationGain)
{
bestInformationGain = loopInformationGain;
bestAttributeLocal = attribute;
bestAttributeValueLocal = null;
System.Console.WriteLine("New best information gain: {0} at {1}",
attribute.ToString(), loopInformationGain);
}
}
}
//System.Console.WriteLine("Information gain on {0}: {1}", attribute.ToString(),
// loopInformationGain);
break;
}
});
bestAttribute = bestAttributeLocal;
bestAttributeValue = bestAttributeValueLocal;
return(bestInformationGain);
}
