/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* Kernel.java
* Copyright (C) 1999 University of Waikato, Hamilton, New Zealand
*
*/
package weka.classifiers.functions.supportVector;
import weka.core.Capabilities;
import weka.core.CapabilitiesHandler;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.RevisionHandler;
import weka.core.SerializedObject;
import weka.core.Utils;
import java.io.Serializable;
import java.util.Enumeration;
import java.util.Vector;
/**
* Abstract kernel.
* Kernels implementing this class must respect Mercer's condition in order
* to ensure a correct behaviour of SMOreg.
*
* @author Eibe Frank (eibe@cs.waikato.ac.nz)
* @author FracPete (fracpete at waikato dot ac dot nz)
* @version $Revision: 1.8 $
*/
public abstract class Kernel
implements Serializable, OptionHandler, CapabilitiesHandler, RevisionHandler {
/** for serialization */
private static final long serialVersionUID = -6102771099905817064L;
/** The dataset */
protected Instances m_data;
/** enables debugging output */
protected boolean m_Debug = false;
/** Turns off all checks */
protected boolean m_ChecksTurnedOff = false;
/**
* Returns a string describing the kernel
*
* @return a description suitable for displaying in the
* explorer/experimenter gui
*/
public abstract String globalInfo();
/**
* Computes the result of the kernel function for two instances.
* If id1 == -1, eval use inst1 instead of an instance in the dataset.
*
* @param id1 the index of the first instance in the dataset
* @param id2 the index of the second instance in the dataset
* @param inst1 the instance corresponding to id1 (used if id1 == -1)
* @return the result of the kernel function
* @throws Exception if something goes wrong
*/
public abstract double eval(int id1, int id2, Instance inst1)
throws Exception;
/**
* 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.
*/
public abstract void clean();
/**
* Returns the number of kernel evaluation performed.
*
* @return the number of kernel evaluation performed.
*/
public abstract int numEvals();
/**
* Returns the number of dot product cache hits.
*
* @return the number of dot product cache hits, or -1 if not supported by this kernel.
*/
public abstract int numCacheHits();
/**
* Returns an enumeration describing the available options.
*
* @return an enumeration of all the available options.
*/
public Enumeration listOptions() {
Vector result;
result = new Vector();
result.addElement(new Option(
"\tEnables debugging output (if available) to be printed.\n"
+ "\t(default: off)",
"D", 0, "-D"));
result.addElement(new Option(
"\tTurns off all checks - use with caution!\n"
+ "\t(default: checks on)",
"no-checks", 0, "-no-checks"));
return result.elements();
}
/**
* Parses a given list of options. <p/>
*
* @param options the list of options as an array of strings
* @throws Exception if an option is not supported
*/
public void setOptions(String[] options) throws Exception {
setDebug(Utils.getFlag('D', options));
setChecksTurnedOff(Utils.getFlag("no-checks", options));
Utils.checkForRemainingOptions(options);
}
/**
* Gets the current settings of the Kernel.
*
* @return an array of strings suitable for passing to setOptions
*/
public String[] getOptions() {
Vector result;
result = new Vector();
if (getDebug())
result.add("-D");
if (getChecksTurnedOff())
result.add("-no-checks");
return (String[]) result.toArray(new String[result.size()]);
}
/**
* Enables or disables the output of debug information (if the derived
* kernel supports that)
*
* @param value whether to output debugging information
*/
public void setDebug(boolean value) {
m_Debug = value;
}
/**
* Gets whether debugging output is turned on or not.
*
* @return true if debugging output is produced.
*/
public boolean getDebug() {
return m_Debug;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String debugTipText() {
return "Turns on the output of debugging information.";
}
/**
* Disables or enables the checks (which could be time-consuming). Use with
* caution!
*
* @param value if true turns off all checks
*/
public void setChecksTurnedOff(boolean value) {
m_ChecksTurnedOff = value;
}
/**
* Returns whether the checks are turned off or not.
*
* @return true if the checks are turned off
*/
public boolean getChecksTurnedOff() {
return m_ChecksTurnedOff;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String checksTurnedOffTipText() {
return "Turns time-consuming checks off - use with caution.";
}
/**
* initializes variables etc.
*
* @param data the data to use
*/
protected void initVars(Instances data) {
m_data = data;
}
/**
* Returns the Capabilities of this kernel. Derived kernels have to
* override this method to enable capabilities.
*
* @return the capabilities of this object
* @see Capabilities
*/
public Capabilities getCapabilities() {
return new Capabilities(this);
}
/**
* builds the kernel with the given data
*
* @param data the data to base the kernel on
* @throws Exception if something goes wrong
*/
public void buildKernel(Instances data) throws Exception {
// does kernel handle the data?
if (!getChecksTurnedOff())
getCapabilities().testWithFail(data);
initVars(data);
}
/**
* Creates a deep copy of the given kernel using serialization.
*
* @param kernel the kernel to copy
* @return a deep copy of the kernel
* @throws Exception if an error occurs
*/
public static Kernel makeCopy(Kernel kernel) throws Exception {
return (Kernel) new SerializedObject(kernel).getObject();
}
/**
* Creates a given number of deep copies of the given kernel using
* serialization.
*
* @param model the kernel to copy
* @param num the number of kernel copies to create.
* @return an array of kernels.
* @throws Exception if an error occurs
*/
public static Kernel[] makeCopies(Kernel model, int num) throws Exception {
if (model == null)
throw new Exception("No model kernel set");
Kernel[] kernels = new Kernel[num];
SerializedObject so = new SerializedObject(model);
for (int i = 0; i < kernels.length; i++)
kernels[i] = (Kernel) so.getObject();
return kernels;
}
/**
* Creates a new instance of a kernel given it's class name and
* (optional) arguments to pass to it's setOptions method.
*
* @param kernelName the fully qualified class name of the classifier
* @param options an array of options suitable for passing to setOptions. May
* be null.
* @return 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
*/
public static Kernel forName(String kernelName, String[] options)
throws Exception {
return (Kernel) Utils.forName(Kernel.class, kernelName, options);
}
}