Package weka.classifiers.functions.supportVector

Class Kernel

java.lang.Object
weka.classifiers.functions.supportVector.Kernel
All Implemented Interfaces:
Serializable, CapabilitiesHandler, OptionHandler, RevisionHandler
Direct Known Subclasses:
CachedKernel, PrecomputedKernelMatrixKernel, StringKernel
public abstract class Kernel extends Object implements Serializable, OptionHandler, CapabilitiesHandler, RevisionHandler
Abstract kernel. Kernels implementing this class must respect Mercer's condition in order to ensure a correct behaviour of SMOreg.
Version:
$Revision: 14516 $
Author:
Eibe Frank (eibe@cs.waikato.ac.nz), FracPete (fracpete at waikato dot ac dot nz)
See Also:

  • Constructor Details

    • Kernel

      public Kernel()

  • Method Details

    • setDoNotCheckCapabilities

      @ProgrammaticProperty public void setDoNotCheckCapabilities(boolean doNotCheckCapabilities)
      These methods remain for backwards compatibility. The first one does nothing, the second one always returns true. Checking capabilities is the responsibility of the class using the kernel.

    • getDoNotCheckCapabilities

      public boolean getDoNotCheckCapabilities()

    • globalInfo

      public abstract String globalInfo()
      Returns a string describing the kernel
      Returns:
      a description suitable for displaying in the explorer/experimenter gui

    • eval

      public abstract double eval(int id1, int id2, Instance inst1) throws Exception
      Computes the result of the kernel function for two instances. If id1 == -1, eval use inst1 instead of an instance in the dataset.
      Parameters:
      id1 - the index of the first instance in the dataset
      id2 - the index of the second instance in the dataset
      inst1 - the instance corresponding to id1 (used if id1 == -1)
      Returns:
      the result of the kernel function
      Throws:
      Exception - if something goes wrong

    • clean

      public abstract void clean()
      Frees the memory used by the kernel. (Useful with kernels which use cache.) This function is called when the training is done. i.e. after that, eval will be called with id1 == -1.

    • numEvals

      public abstract int numEvals()
      Returns the number of kernel evaluation performed.
      Returns:
      the number of kernel evaluation performed.

    • numCacheHits

      public abstract int numCacheHits()
      Returns the number of dot product cache hits.
      Returns:
      the number of dot product cache hits, or -1 if not supported by this kernel.

    • listOptions

      public Enumeration<Option> 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(String[] options) throws Exception
      Parses a given list of options.

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

    • getOptions

      public String[] getOptions()
      Gets the current settings of the Kernel.
      Specified by:
      getOptions in interface OptionHandler
      Returns:
      an array of strings suitable for passing to setOptions

    • setDebug

      public void setDebug(boolean value)
      Enables or disables the output of debug information (if the derived kernel supports that)
      Parameters:
      value - whether to output debugging information

    • getDebug

      public boolean getDebug()
      Gets whether debugging output is turned on or not.
      Returns:
      true if debugging output is produced.

    • debugTipText

      public String debugTipText()
      Returns the tip text for this property
      Returns:
      tip text for this property suitable for displaying in the explorer/experimenter gui

    • setChecksTurnedOff

      @ProgrammaticProperty public void setChecksTurnedOff(boolean value)
      These methods remain for backwards compatibility. The first one does nothing, the second one always returns true. Checking capabilities is the responsibility of the class using the kernel.

    • getChecksTurnedOff

      public boolean getChecksTurnedOff()

    • getCapabilities

      public Capabilities getCapabilities()
      Returns the Capabilities of this kernel. Derived kernels have to override this method to enable capabilities.
      Specified by:
      getCapabilities in interface CapabilitiesHandler
      Returns:
      the capabilities of this object
      See Also:

    • getRevision

      public String getRevision()
      Returns the revision string.
      Specified by:
      getRevision in interface RevisionHandler
      Returns:
      the revision

    • buildKernel

      public void buildKernel(Instances data) throws Exception
      builds the kernel with the given data
      Parameters:
      data - the data to base the kernel on
      Throws:
      Exception - if something goes wrong

    • makeCopy

      public static Kernel makeCopy(Kernel kernel) throws Exception
      Creates a shallow copy of the kernel (if it implements Copyable) otherwise a deep copy using serialization.
      Parameters:
      kernel - the kernel to copy
      Returns:
      a shallow or deep copy of the kernel
      Throws:
      Exception - if an error occurs

    • makeCopies

      public static Kernel[] makeCopies(Kernel model, int num) throws Exception
      Creates a given number of deep or shallow (if the kernel implements Copyable) copies of the given kernel using serialization.
      Parameters:
      model - the kernel to copy
      num - the number of kernel copies to create.
      Returns:
      an array of kernels.
      Throws:
      Exception - if an error occurs

    • forName

      public static Kernel forName(String kernelName, String[] options) throws Exception
      Creates a new instance of a kernel given it's class name and (optional) arguments to pass to it's setOptions method.
      Parameters:
      kernelName - the fully qualified class name of the classifier
      options - an array of options suitable for passing to setOptions. May be null.
      Returns:
      the newly created classifier, ready for use.
      Throws:
      Exception - if the classifier name is invalid, or the options supplied are not acceptable to the classifier