weka.estimators
Class Estimator

java.lang.Object
  extended by weka.estimators.Estimator
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, CapabilitiesHandler, OptionHandler, RevisionHandler
Direct Known Subclasses:
DiscreteEstimator, DiscreteEstimatorBayes, KernelEstimator, MahalanobisEstimator, NormalEstimator, PoissonEstimator

public abstract class Estimator
extends java.lang.Object
implements java.lang.Cloneable, java.io.Serializable, OptionHandler, CapabilitiesHandler, RevisionHandler

Abstract class for all estimators. Example code for a nonincremental estimator

   // create a histogram for estimation
   EqualWidthEstimator est = new EqualWidthEstimator();
   est.addValues(instances, attrIndex);
 
Example code for an incremental estimator (incremental estimators must implement interface IncrementalEstimator)
   // Create a discrete estimator that takes values 0 to 9
   DiscreteEstimator newEst = new DiscreteEstimator(10, true);

   // Create 50 random integers first predicting the probability of the
   // value, then adding the value to the estimator
   Random r = new Random(seed);
   for(int i = 0; i < 50; i++) {
     current = Math.abs(r.nextInt() % 10);
     System.out.println(newEst);
     System.out.println("Prediction for " + current 
                        + " = " + newEst.getProbability(current));
     newEst.addValue(current, 1);
   }
 
Example code for a main method for an estimator.

 public static void main(String [] argv) {

   try {
     LoglikeliEstimator est = new LoglikeliEstimator();      
     Estimator.buildEstimator((Estimator) est, argv, false);      
     System.out.println(est.toString());
   } catch (Exception ex) {
     ex.printStackTrace();
     System.out.println(ex.getMessage());
   }
 }
 

Version:
$Revision: 5539 $
Author:
Gabi Schmidberger (gabi@cs.waikato.ac.nz), Len Trigg (trigg@cs.waikato.ac.nz)
See Also:
Serialized Form

Constructor Summary
Estimator()
           
 
Method Summary
 void addValue(double data, double weight)
          Add a new data value to the current estimator.
 void addValues(Instances data, int attrIndex)
          Initialize the estimator with a new dataset.
 void addValues(Instances data, int attrIndex, double min, double max, double factor)
          Initialize the estimator with all values of one attribute of a dataset.
 void addValues(Instances data, int attrIndex, int classIndex, int classValue)
          Initialize the estimator using only the instance of one class.
 void addValues(Instances data, int attrIndex, int classIndex, int classValue, double min, double max)
          Initialize the estimator using only the instance of one class.
static void buildEstimator(Estimator est, Instances instances, int attrIndex, int classIndex, int classValueIndex, boolean isIncremental)
           
static void buildEstimator(Estimator est, java.lang.String[] options, boolean isIncremental)
          Build an estimator using the options.
static Estimator clone(Estimator model)
          Creates a deep copy of the given estimator using serialization.
 java.lang.String debugTipText()
          Returns the tip text for this property
 boolean equals(java.lang.Object obj)
          Tests whether the current estimation object is equal to another estimation object
static Estimator forName(java.lang.String name, java.lang.String[] options)
          Creates a new instance of a estimatorr given it's class name and (optional) arguments to pass to it's setOptions method.
 Capabilities getCapabilities()
          Returns the Capabilities of this Estimator.
 boolean getDebug()
          Get whether debugging is turned on.
 java.lang.String[] getOptions()
          Gets the current settings of the Estimator.
abstract  double getProbability(double data)
          Get a probability estimate for a value.
 java.util.Enumeration listOptions()
          Returns an enumeration describing the available options.
static Estimator[] makeCopies(Estimator model, int num)
          Creates a given number of deep copies of the given estimator using serialization.
static Estimator makeCopy(Estimator model)
          Creates a deep copy of the given estimator using serialization.
 void setDebug(boolean debug)
          Set debugging mode.
 void setOptions(java.lang.String[] options)
          Parses a given list of options.
 void testCapabilities(Instances data, int attrIndex)
          Test if the estimator can handle the data.
 
Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface weka.core.RevisionHandler
getRevision
 

Constructor Detail

Estimator

public Estimator()
Method Detail

addValue

public void addValue(double data,
                     double weight)
Add a new data value to the current estimator.

Parameters:
data - the new data value
weight - the weight assigned to the data value

addValues

public void addValues(Instances data,
                      int attrIndex)
               throws java.lang.Exception
Initialize the estimator with a new dataset. Finds min and max first.

Parameters:
data - the dataset used to build this estimator
attrIndex - attribute the estimator is for
Throws:
java.lang.Exception - if building of estimator goes wrong

addValues

public void addValues(Instances data,
                      int attrIndex,
                      double min,
                      double max,
                      double factor)
               throws java.lang.Exception
Initialize the estimator with all values of one attribute of a dataset. Some estimator might ignore the min and max values.

Parameters:
data - the dataset used to build this estimator
attrIndex - attribute the estimator is for
min - minimal border of range
max - maximal border of range
factor - number of instances has been reduced to that factor
Throws:
java.lang.Exception - if building of estimator goes wrong

addValues

public void addValues(Instances data,
                      int attrIndex,
                      int classIndex,
                      int classValue)
               throws java.lang.Exception
Initialize the estimator using only the instance of one class. It is using the values of one attribute only.

Parameters:
data - the dataset used to build this estimator
attrIndex - attribute the estimator is for
classIndex - index of the class attribute
classValue - the class value
Throws:
java.lang.Exception - if building of estimator goes wrong

addValues

public void addValues(Instances data,
                      int attrIndex,
                      int classIndex,
                      int classValue,
                      double min,
                      double max)
               throws java.lang.Exception
Initialize the estimator using only the instance of one class. It is using the values of one attribute only.

Parameters:
data - the dataset used to build this estimator
attrIndex - attribute the estimator is for
classIndex - index of the class attribute
classValue - the class value
min - minimal value of this attribute
max - maximal value of this attribute
Throws:
java.lang.Exception - if building of estimator goes wrong

getProbability

public abstract double getProbability(double data)
Get a probability estimate for a value.

Parameters:
data - the value to estimate the probability of
Returns:
the estimated probability of the supplied value

buildEstimator

public static void buildEstimator(Estimator est,
                                  java.lang.String[] options,
                                  boolean isIncremental)
                           throws java.lang.Exception
Build an estimator using the options. The data is given in the options.

Parameters:
est - the estimator used
options - the list of options
isIncremental - true if estimator is incremental
Throws:
java.lang.Exception - if something goes wrong or the user requests help on command options

buildEstimator

public static void buildEstimator(Estimator est,
                                  Instances instances,
                                  int attrIndex,
                                  int classIndex,
                                  int classValueIndex,
                                  boolean isIncremental)
                           throws java.lang.Exception
Throws:
java.lang.Exception

clone

public static Estimator clone(Estimator model)
                       throws java.lang.Exception
Creates a deep copy of the given estimator using serialization.

Parameters:
model - the estimator to copy
Returns:
a deep copy of the estimator
Throws:
java.lang.Exception - if an error occurs

makeCopy

public static Estimator makeCopy(Estimator model)
                          throws java.lang.Exception
Creates a deep copy of the given estimator using serialization.

Parameters:
model - the estimator to copy
Returns:
a deep copy of the estimator
Throws:
java.lang.Exception - if an error occurs

makeCopies

public static Estimator[] makeCopies(Estimator model,
                                     int num)
                              throws java.lang.Exception
Creates a given number of deep copies of the given estimator using serialization.

Parameters:
model - the estimator to copy
num - the number of estimator copies to create.
Returns:
an array of estimators.
Throws:
java.lang.Exception - if an error occurs

equals

public boolean equals(java.lang.Object obj)
Tests whether the current estimation object is equal to another estimation object

Overrides:
equals in class java.lang.Object
Parameters:
obj - the object to compare against
Returns:
true if the two objects are equal

listOptions

public java.util.Enumeration listOptions()
Returns an enumeration describing the available options.

Specified by:
listOptions in interface OptionHandler
Returns:
an enumeration of all the available options.

setOptions

public void setOptions(java.lang.String[] options)
                throws java.lang.Exception
Parses a given list of options. Valid options are:

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

Specified by:
setOptions in interface OptionHandler
Parameters:
options - the list of options as an array of strings
Throws:
java.lang.Exception - if an option is not supported

getOptions

public java.lang.String[] getOptions()
Gets the current settings of the Estimator.

Specified by:
getOptions in interface OptionHandler
Returns:
an array of strings suitable for passing to setOptions

forName

public static Estimator forName(java.lang.String name,
                                java.lang.String[] options)
                         throws java.lang.Exception
Creates a new instance of a estimatorr given it's class name and (optional) arguments to pass to it's setOptions method. If the classifier implements OptionHandler and the options parameter is non-null, the classifier will have it's options set.

Parameters:
name - the fully qualified class name of the estimatorr
options - an array of options suitable for passing to setOptions. May be null.
Returns:
the newly created classifier, ready for use.
Throws:
java.lang.Exception - if the classifier name is invalid, or the options supplied are not acceptable to the classifier

setDebug

public void setDebug(boolean debug)
Set debugging mode.

Parameters:
debug - true if debug output should be printed

getDebug

public boolean getDebug()
Get whether debugging is turned on.

Returns:
true if debugging output is on

debugTipText

public java.lang.String debugTipText()
Returns the tip text for this property

Returns:
tip text for this property suitable for displaying in the explorer/experimenter gui

getCapabilities

public Capabilities getCapabilities()
Returns the Capabilities of this Estimator. Derived estimators have to override this method to enable capabilities.

Specified by:
getCapabilities in interface CapabilitiesHandler
Returns:
the capabilities of this object
See Also:
Capabilities

testCapabilities

public void testCapabilities(Instances data,
                             int attrIndex)
                      throws java.lang.Exception
Test if the estimator can handle the data.

Parameters:
data - the dataset the estimator takes an attribute from
attrIndex - the index of the attribute
Throws:
java.lang.Exception
See Also:
Capabilities