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## weka.classifiers.trees.lmt
Class LogisticBase

    java.lang.Object
      weka.classifiers.Classifier
          weka.classifiers.trees.lmt.LogisticBase

All Implemented Interfaces:
  java.io.Serializable, java.lang.Cloneable, CapabilitiesHandler, OptionHandler, RevisionHandler, WeightedInstancesHandler

Direct Known Subclasses:
  FTtree, LMTNode

    public class LogisticBase

extends Classifier
implements WeightedInstancesHandler

Base/helper class for building logistic regression models with the LogitBoost algorithm. Used for building logistic model trees (weka.classifiers.trees.lmt.LMT) and standalone logistic regression (weka.classifiers.functions.SimpleLogistic). Valid options are:

     -D
      If set, classifier is run in debug mode and
      may output additional info to the console

Version:
  $Revision: 1.9 $
Author:
  Niels Landwehr, Marc Sumner
See Also:
  Serialized Form

Constructor Summary
`LogisticBase()` Constructor that creates LogisticBase object with standard options.
`LogisticBase(int numBoostingIterations, boolean useCrossValidation, boolean errorOnProbabilities)` Constructor to create LogisticBase object.

Method Summary
`void` | `buildClassifier(Instances data)` Builds the logistic regression model usiing LogitBoost.
`void` | `cleanup()` Cleanup in order to save memory.
`double[]` | `distributionForInstance(Instance instance)` Returns class probabilities for an instance.
`int` | `getMaxIterations()` Returns the maxIterations parameter.
`int` | `getNumRegressions()` The number of LogitBoost iterations performed (= the number of simple regression functions fit).
`java.lang.String` | `getRevision()` Returns the revision string.
`boolean` | `getUseAIC()` Get the value of useAIC.
`int[][]` | `getUsedAttributes()` Returns an array of the indices of the attributes used in the logistic model.
`double` | `getWeightTrimBeta()` Get the value of weightTrimBeta.
`double` | `percentAttributesUsed()` Returns the fraction of all attributes in the data that are used in the logistic model (in percent).
`void` | `setHeuristicStop(int heuristicStop)` Sets the option "heuristicStop".
`void` | `setMaxIterations(int maxIterations)` Sets the parameter "maxIterations".
`void` | `setUseAIC(boolean c)` Set the value of useAIC.
`void` | `setWeightTrimBeta(double w)` Sets the option "weightTrimBeta".
`java.lang.String` | `toString()` Returns a description of the logistic model (i.e., attributes and coefficients).

Methods inherited from class weka.classifiers.Classifier
`classifyInstance, debugTipText, forName, getCapabilities, getDebug, getOptions, listOptions, makeCopies, makeCopy, setDebug, setOptions`

Methods inherited from class java.lang.Object
`equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Constructor Detail

### LogisticBase

    public LogisticBase()

  Constructor that creates LogisticBase object with standard options.

### LogisticBase

    public LogisticBase(int numBoostingIterations,
                        boolean useCrossValidation,
                        boolean errorOnProbabilities)

  Constructor to create LogisticBase object.

  Parameters:
    `numBoostingIterations` - fixed number of iterations for LogitBoost (if negative, use cross-validation or stopping criterion on the training data).
    `useCrossValidation` - cross-validate number of LogitBoost iterations (if false, use stopping criterion on the training data).
    `errorOnProbabilities` - if true, use error on probabilities instead of misclassification for stopping criterion of LogitBoost

Method Detail

### buildClassifier

    public void buildClassifier(Instances data)
                         throws java.lang.Exception

  Builds the logistic regression model usiing LogitBoost.

  Specified by:
    `buildClassifier` in class `Classifier`
  Parameters:
    `data` - the training data
  Throws:
    `java.lang.Exception` - if something goes wrong

### getUsedAttributes

    public int[][] getUsedAttributes()

  Returns an array of the indices of the attributes used in the logistic model. The first dimension is the class, the second dimension holds a list of attribute indices. Attribute indices start at zero.

  Returns:
    the array of attribute indices

### getNumRegressions

    public int getNumRegressions()

  The number of LogitBoost iterations performed (= the number of simple regression functions fit).

  Returns:
    the number of LogitBoost iterations performed

### getWeightTrimBeta

    public double getWeightTrimBeta()

  Get the value of weightTrimBeta.

  Returns:
    Value of weightTrimBeta.

### getUseAIC

    public boolean getUseAIC()

  Get the value of useAIC.

  Returns:
    Value of useAIC.

### setMaxIterations

    public void setMaxIterations(int maxIterations)

  Sets the parameter "maxIterations".

  Parameters:
    `maxIterations` - the maximum iterations

### setHeuristicStop

    public void setHeuristicStop(int heuristicStop)

  Sets the option "heuristicStop".

  Parameters:
    `heuristicStop` - the heuristic stop to use

### setWeightTrimBeta

    public void setWeightTrimBeta(double w)

  Sets the option "weightTrimBeta".

### setUseAIC

    public void setUseAIC(boolean c)

  Set the value of useAIC.

  Parameters:
    `c` - Value to assign to useAIC.

### getMaxIterations

    public int getMaxIterations()

  Returns the maxIterations parameter.

  Returns:
    the maximum iteration

### percentAttributesUsed

    public double percentAttributesUsed()

  Returns the fraction of all attributes in the data that are used in the logistic model (in percent). An attribute is used in the model if it is used in any of the models for the different classes.

  Returns:
    the fraction of all attributes that are used

### toString

    public java.lang.String toString()

  Returns a description of the logistic model (i.e., attributes and coefficients).

  Overrides:
    `toString` in class `java.lang.Object`
  Returns:
    the description of the model

### distributionForInstance

    public double[] distributionForInstance(Instance instance)
                                     throws java.lang.Exception

  Returns class probabilities for an instance.

  Overrides:
    `distributionForInstance` in class `Classifier`
  Parameters:
    `instance` - the instance to compute the distribution for
  Returns:
    the class probabilities
  Throws:
    `java.lang.Exception` - if distribution can't be computed successfully

### cleanup

    public void cleanup()

  Cleanup in order to save memory.

### getRevision

    public java.lang.String getRevision()

  Returns the revision string.

  Specified by:
    `getRevision` in interface `RevisionHandler`
  Overrides:
    `getRevision` in class `Classifier`
  Returns:
    the revision

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