/// <summary> Creates a cost matrix that is a copy of another.
///
/// </summary>
/// <param name="toCopy">the matrix to copy.
/// </param>
public CostMatrix(CostMatrix toCopy):base(toCopy.size(), toCopy.size())
{
for (int x = 0; x < toCopy.size(); x++)
for (int y = 0; y < toCopy.size(); y++)
setXmlElement(x, y, toCopy.getXmlElement(x, y));
}
/// <summary> Initializes all the counters for the evaluation and also takes a
/// cost matrix as parameter.
/// Use <code>useNoPriors()</code> if the dataset is the test set and you
/// can't initialize with the priors from the training set via
/// <code>setPriors(Instances)</code>.
///
/// </summary>
/// <param name="data"> set of training instances, to get some header
/// information and prior class distribution information
/// </param>
/// <param name="costMatrix"> the cost matrix---if null, default costs will be used
/// </param>
/// <throws> Exception if cost matrix is not compatible with </throws>
/// <summary> data, the class is not defined or the class is numeric
/// </summary>
/// <seealso cref="useNoPriors()">
/// </seealso>
/// <seealso cref="setPriors(Instances)">
/// </seealso>
public Evaluation(Instances data, CostMatrix costMatrix)
{
m_NumClasses = data.numClasses();
m_NumFolds = 1;
m_ClassIsNominal = data.classAttribute().Nominal;
if (m_ClassIsNominal)
{
double[][] tmpArray = new double[m_NumClasses][];
for (int i = 0; i < m_NumClasses; i++)
{
tmpArray[i] = new double[m_NumClasses];
}
m_ConfusionMatrix = tmpArray;
m_ClassNames = new System.String[m_NumClasses];
for (int i = 0; i < m_NumClasses; i++)
{
m_ClassNames[i] = data.classAttribute().value_Renamed(i);
}
}
m_CostMatrix = costMatrix;
if (m_CostMatrix != null)
{
if (!m_ClassIsNominal)
{
throw new System.Exception("Class has to be nominal if cost matrix " + "given!");
}
if (m_CostMatrix.size() != m_NumClasses)
{
throw new System.Exception("Cost matrix not compatible with data!");
}
}
m_ClassPriors = new double[m_NumClasses];
Priors = data;
m_MarginCounts = new double[k_MarginResolution + 1];
}
/// <summary> Applies the cost matrix to a set of instances. If a random number generator is
/// supplied the instances will be resampled, otherwise they will be rewighted.
/// Adapted from code once sitting in Instances.java
///
/// </summary>
/// <param name="data">the instances to reweight.
/// </param>
/// <param name="random">a random number generator for resampling, if null then instances are
/// rewighted.
/// </param>
/// <returns> a new dataset reflecting the cost of misclassification.
/// </returns>
/// <exception cref="Exception">if the data has no class or the matrix in inappropriate.
/// </exception>
public virtual Instances applyCostMatrix(Instances data, System.Random random)
{
double sumOfWeightFactors = 0, sumOfMissClassWeights, sumOfWeights;
double[] weightOfInstancesInClass, weightFactor, weightOfInstances;
Instances newData;
if (data.classIndex() < 0)
{
throw new System.Exception("Class index is not set!");
}
if (size() != data.numClasses())
{
throw new System.Exception("Misclassification cost matrix has " + "wrong format!");
}
weightFactor = new double[data.numClasses()];
weightOfInstancesInClass = new double[data.numClasses()];
for (int j = 0; j < data.numInstances(); j++)
{
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
weightOfInstancesInClass[(int) data.instance(j).classValue()] += data.instance(j).weight();
}
sumOfWeights = Utils.sum(weightOfInstancesInClass);
// normalize the matrix if not already
for (int i = 0; i < size(); i++)
if (!Utils.eq(getXmlElement(i, i), 0))
{
CostMatrix normMatrix = new CostMatrix(this);
normMatrix.normalize();
return normMatrix.applyCostMatrix(data, random);
}
for (int i = 0; i < data.numClasses(); i++)
{
// Using Kai Ming Ting's formula for deriving weights for
// the classes and Breiman's heuristic for multiclass
// problems.
sumOfMissClassWeights = 0;
for (int j = 0; j < data.numClasses(); j++)
{
if (Utils.sm(getXmlElement(i, j), 0))
{
throw new System.Exception("Neg. weights in misclassification " + "cost matrix!");
}
sumOfMissClassWeights += getXmlElement(i, j);
}
weightFactor[i] = sumOfMissClassWeights * sumOfWeights;
sumOfWeightFactors += sumOfMissClassWeights * weightOfInstancesInClass[i];
}
for (int i = 0; i < data.numClasses(); i++)
{
weightFactor[i] /= sumOfWeightFactors;
}
// Store new weights
weightOfInstances = new double[data.numInstances()];
for (int i = 0; i < data.numInstances(); i++)
{
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
weightOfInstances[i] = data.instance(i).weight() * weightFactor[(int) data.instance(i).classValue()];
}
// Change instances weight or do resampling
if (random != null)
{
return data.resampleWithWeights(random, weightOfInstances);
}
else
{
Instances instances = new Instances(data);
for (int i = 0; i < data.numInstances(); i++)
{
instances.instance(i).Weight = weightOfInstances[i];
}
return instances;
}
}
/// <summary> Attempts to load a cost matrix.
///
/// </summary>
/// <param name="costFileName">the filename of the cost matrix
/// </param>
/// <param name="numClasses">the number of classes that should be in the cost matrix
/// (only used if the cost file is in old format).
/// </param>
/// <returns> a <code>CostMatrix</code> value, or null if costFileName is empty
/// </returns>
/// <throws> Exception if an error occurs. </throws>
protected internal static CostMatrix handleCostOption(System.String costFileName, int numClasses)
{
if ((costFileName != null) && (costFileName.Length != 0))
{
System.Console.Out.WriteLine("NOTE: The behaviour of the -m option has changed between WEKA 3.0" + " and WEKA 3.1. -m now carries out cost-sensitive *evaluation*" + " only. For cost-sensitive *prediction*, use one of the" + " cost-sensitive metaschemes such as" + " weka.classifiers.meta.CostSensitiveClassifier or" + " weka.classifiers.meta.MetaCost");
//UPGRADE_ISSUE: Class hierarchy differences between 'java.io.Reader' and 'System.IO.StreamReader' may cause compilation errors. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1186'"
System.IO.StreamReader costReader = null;
try
{
//UPGRADE_TODO: The differences in the expected value of parameters for constructor 'java.io.BufferedReader.BufferedReader' may cause compilation errors. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1092'"
//UPGRADE_WARNING: At least one expression was used more than once in the target code. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1181'"
//UPGRADE_TODO: Constructor 'java.io.FileReader.FileReader' was converted to 'System.IO.StreamReader' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073'"
costReader = new System.IO.StreamReader(new System.IO.StreamReader(costFileName, System.Text.Encoding.Default).BaseStream, new System.IO.StreamReader(costFileName, System.Text.Encoding.Default).CurrentEncoding);
}
catch (System.Exception e)
{
//UPGRADE_TODO: The equivalent in .NET for method 'java.lang.Throwable.getMessage' may return a different value. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1043'"
throw new System.Exception("Can't open file " + e.Message + '.');
}
try
{
// First try as a proper cost matrix format
return new CostMatrix(costReader);
}
catch (System.Exception ex)
{
try
{
// Now try as the poxy old format :-)
//System.err.println("Attempting to read old format cost file");
try
{
costReader.Close(); // Close the old one
//UPGRADE_TODO: The differences in the expected value of parameters for constructor 'java.io.BufferedReader.BufferedReader' may cause compilation errors. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1092'"
//UPGRADE_WARNING: At least one expression was used more than once in the target code. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1181'"
//UPGRADE_TODO: Constructor 'java.io.FileReader.FileReader' was converted to 'System.IO.StreamReader' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073'"
costReader = new System.IO.StreamReader(new System.IO.StreamReader(costFileName, System.Text.Encoding.Default).BaseStream, new System.IO.StreamReader(costFileName, System.Text.Encoding.Default).CurrentEncoding);
}
catch (System.Exception e)
{
//UPGRADE_TODO: The equivalent in .NET for method 'java.lang.Throwable.getMessage' may return a different value. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1043'"
throw new System.Exception("Can't open file " + e.Message + '.');
}
CostMatrix costMatrix = new CostMatrix(numClasses);
//System.err.println("Created default cost matrix");
costMatrix.readOldFormat(costReader);
return costMatrix;
//System.err.println("Read old format");
}
catch (System.Exception e2)
{
// re-throw the original exception
//System.err.println("Re-throwing original exception");
throw ex;
}
}
}
else
{
return null;
}
}
