private DecisionTreeOutputProperties CloneOutputProperties(DecisionTreeOutputProperties outputProperties)
{
return(new DecisionTreeOutputProperties()
{
DataCount = outputProperties.DataCount,
OutputDistribution = outputProperties.OutputDistribution.ToDictionary(x => x.Key, x => x.Value)
});
}
Dictionary <FeatureValue, TreeNode> BranchContinious(Feature feature, IQueryable <T> data, TreeNode parentNode, out double splitQuality)
{
IQueryable <InputOutputPair> orderedInputOutput = BranchContiniousData(feature, data);
var lowerNode = new DecisionTreeOutputProperties()
{
DataCount = 0,
OutputDistribution = (parentNode.OutputProperties as DecisionTreeOutputProperties).OutputDistribution.ToDictionary(x => x.Key, x => 0)
};
var higherNode = CloneOutputProperties(parentNode.OutputProperties as DecisionTreeOutputProperties);
var maxSplitQuality = double.MinValue;
DecisionTreeOutputProperties maxLowerNode = null;
object limitInput = null;
foreach (InputOutputPair value in orderedInputOutput)
{
lowerNode.DataCount++;
higherNode.DataCount--;
lowerNode.OutputDistribution[value.Output]++;
higherNode.OutputDistribution[value.Output]--;
var tempSplitQuality = options.SplitQualifier(lowerNode) * lowerNode.DataCount + options.SplitQualifier(higherNode) * higherNode.DataCount;
if (tempSplitQuality > maxSplitQuality)
{
maxSplitQuality = tempSplitQuality;
maxLowerNode = CloneOutputProperties(lowerNode);
limitInput = value.Input;
}
}
splitQuality = maxSplitQuality;
if (maxLowerNode == null)
{
return(new Dictionary <FeatureValue, TreeNode>());
}
var result = new Dictionary <FeatureValue, TreeNode>();
result.Add(new ContiniousFeatureValue()
{
To = limitInput as IComparable,
},
new TreeNode()
{
OutputProperties = lowerNode, Parent = parentNode
});
result.Add(new ContiniousFeatureValue()
{
From = limitInput as IComparable,
},
new TreeNode()
{
OutputProperties = higherNode, Parent = parentNode
});
return(result);
}
