public static double Calculate(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree solution, double lowerEstimationLimit, double upperEstimationLimit, IRegressionProblemData problemData, IEnumerable <int> rows, bool applyLinearScaling)
{
IEnumerable <double> estimatedValues = interpreter.GetSymbolicExpressionTreeValues(solution, problemData.Dataset, rows);
IEnumerable <double> targetValues = problemData.Dataset.GetDoubleValues(problemData.TargetVariable, rows);
OnlineCalculatorError errorState;
double mae;
if (applyLinearScaling)
{
var maeCalculator = new OnlineMeanAbsoluteErrorCalculator();
CalculateWithScaling(targetValues, estimatedValues, lowerEstimationLimit, upperEstimationLimit, maeCalculator, problemData.Dataset.Rows);
errorState = maeCalculator.ErrorState;
mae = maeCalculator.MeanAbsoluteError;
}
else
{
IEnumerable <double> boundedEstimatedValues = estimatedValues.LimitToRange(lowerEstimationLimit, upperEstimationLimit);
mae = OnlineMeanAbsoluteErrorCalculator.Calculate(targetValues, boundedEstimatedValues, out errorState);
}
if (errorState != OnlineCalculatorError.None)
{
return(double.NaN);
}
return(mae);
}
/// <summary>
/// Takes two parent individuals P0 and P1.
/// Randomly choose a node i from the first parent, then get a node j from the second parent that matches the semantic similarity criteria.
/// </summary>
public static ISymbolicExpressionTree Cross(IRandom random, ISymbolicExpressionTree parent0, ISymbolicExpressionTree parent1, ISymbolicDataAnalysisExpressionTreeInterpreter interpreter,
T problemData, List <int> rows, int maxDepth, int maxLength, DoubleRange range)
{
var crossoverPoints0 = new List <CutPoint>();
parent0.Root.ForEachNodePostfix((n) => {
if (n.Parent != null && n.Parent != parent0.Root)
{
crossoverPoints0.Add(new CutPoint(n.Parent, n));
}
});
var crossoverPoint0 = crossoverPoints0.SampleRandom(random);
int level = parent0.Root.GetBranchLevel(crossoverPoint0.Child);
int length = parent0.Root.GetLength() - crossoverPoint0.Child.GetLength();
var allowedBranches = new List <ISymbolicExpressionTreeNode>();
parent1.Root.ForEachNodePostfix((n) => {
if (n.Parent != null && n.Parent != parent1.Root)
{
if (n.GetDepth() + level <= maxDepth && n.GetLength() + length <= maxLength && crossoverPoint0.IsMatchingPointType(n))
{
allowedBranches.Add(n);
}
}
});
if (allowedBranches.Count == 0)
{
return(parent0);
}
var dataset = problemData.Dataset;
// create symbols in order to improvize an ad-hoc tree so that the child can be evaluated
var rootSymbol = new ProgramRootSymbol();
var startSymbol = new StartSymbol();
var tree0 = CreateTreeFromNode(random, crossoverPoint0.Child, rootSymbol, startSymbol);
List <double> estimatedValues0 = interpreter.GetSymbolicExpressionTreeValues(tree0, dataset, rows).ToList();
crossoverPoint0.Child.Parent = crossoverPoint0.Parent; // restore parent
ISymbolicExpressionTreeNode selectedBranch = null;
// pick the first node that fulfills the semantic similarity conditions
foreach (var node in allowedBranches)
{
var parent = node.Parent;
var tree1 = CreateTreeFromNode(random, node, startSymbol, rootSymbol); // this will affect node.Parent
List <double> estimatedValues1 = interpreter.GetSymbolicExpressionTreeValues(tree1, dataset, rows).ToList();
node.Parent = parent; // restore parent
OnlineCalculatorError errorState;
double ssd = OnlineMeanAbsoluteErrorCalculator.Calculate(estimatedValues0, estimatedValues1, out errorState);
if (range.Start <= ssd && ssd <= range.End)
{
selectedBranch = node;
break;
}
}
// perform the actual swap
if (selectedBranch != null)
{
Swap(crossoverPoint0, selectedBranch);
}
return(parent0);
}
protected override void Run()
{
IRegressionProblemData problemData = Problem.ProblemData;
IEnumerable <string> selectedInputVariables = problemData.AllowedInputVariables;
int nSv;
ISupportVectorMachineModel model;
Run(problemData, selectedInputVariables, SvmType.Value, KernelType.Value, Cost.Value, Nu.Value, Gamma.Value, Epsilon.Value, Degree.Value, out model, out nSv);
if (CreateSolution)
{
var solution = new SupportVectorRegressionSolution((SupportVectorMachineModel)model, (IRegressionProblemData)problemData.Clone());
Results.Add(new Result("Support vector regression solution", "The support vector regression solution.", solution));
}
Results.Add(new Result("Number of support vectors", "The number of support vectors of the SVR solution.", new IntValue(nSv)));
{
// calculate regression model metrics
var ds = problemData.Dataset;
var trainRows = problemData.TrainingIndices;
var testRows = problemData.TestIndices;
var yTrain = ds.GetDoubleValues(problemData.TargetVariable, trainRows);
var yTest = ds.GetDoubleValues(problemData.TargetVariable, testRows);
var yPredTrain = model.GetEstimatedValues(ds, trainRows).ToArray();
var yPredTest = model.GetEstimatedValues(ds, testRows).ToArray();
OnlineCalculatorError error;
var trainMse = OnlineMeanSquaredErrorCalculator.Calculate(yPredTrain, yTrain, out error);
if (error != OnlineCalculatorError.None)
{
trainMse = double.MaxValue;
}
var testMse = OnlineMeanSquaredErrorCalculator.Calculate(yPredTest, yTest, out error);
if (error != OnlineCalculatorError.None)
{
testMse = double.MaxValue;
}
Results.Add(new Result("Mean squared error (training)", "The mean of squared errors of the SVR solution on the training partition.", new DoubleValue(trainMse)));
Results.Add(new Result("Mean squared error (test)", "The mean of squared errors of the SVR solution on the test partition.", new DoubleValue(testMse)));
var trainMae = OnlineMeanAbsoluteErrorCalculator.Calculate(yPredTrain, yTrain, out error);
if (error != OnlineCalculatorError.None)
{
trainMae = double.MaxValue;
}
var testMae = OnlineMeanAbsoluteErrorCalculator.Calculate(yPredTest, yTest, out error);
if (error != OnlineCalculatorError.None)
{
testMae = double.MaxValue;
}
Results.Add(new Result("Mean absolute error (training)", "The mean of absolute errors of the SVR solution on the training partition.", new DoubleValue(trainMae)));
Results.Add(new Result("Mean absolute error (test)", "The mean of absolute errors of the SVR solution on the test partition.", new DoubleValue(testMae)));
var trainRelErr = OnlineMeanAbsolutePercentageErrorCalculator.Calculate(yPredTrain, yTrain, out error);
if (error != OnlineCalculatorError.None)
{
trainRelErr = double.MaxValue;
}
var testRelErr = OnlineMeanAbsolutePercentageErrorCalculator.Calculate(yPredTest, yTest, out error);
if (error != OnlineCalculatorError.None)
{
testRelErr = double.MaxValue;
}
Results.Add(new Result("Average relative error (training)", "The mean of relative errors of the SVR solution on the training partition.", new DoubleValue(trainRelErr)));
Results.Add(new Result("Average relative error (test)", "The mean of relative errors of the SVR solution on the test partition.", new DoubleValue(testRelErr)));
}
}