/*
* 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.
*/
/*
* SVMLightLoader.java
* Copyright (C) 2006 University of Waikato, Hamilton, NZ
*
*/
package weka.core.converters;
import weka.core.Attribute;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.RevisionUtils;
import weka.core.SparseInstance;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.ArrayList;
/**
<!-- globalinfo-start -->
* Reads a source that is in svm light format.<br/>
* <br/>
* For more information about svm light see:<br/>
* <br/>
* http://svmlight.joachims.org/
* <p/>
<!-- globalinfo-end -->
*
* @author FracPete (fracpete at waikato dot ac dot nz)
* @version $Revision: 5953 $
* @see Loader
*/
public class SVMLightLoader
extends AbstractFileLoader
implements BatchConverter, URLSourcedLoader {
/** for serialization. */
private static final long serialVersionUID = 4988360125354664417L;
/** the file extension. */
public static String FILE_EXTENSION = ".dat";
/** the url. */
protected String m_URL = "http://";
/** The reader for the source file. */
protected transient Reader m_sourceReader = null;
/** the buffer of the rows read so far. */
protected Vector<double[]> m_Buffer = null;
/**
* Returns a string describing this Loader.
*
* @return a description of the Loader suitable for
* displaying in the explorer/experimenter gui
*/
public String globalInfo() {
return
"Reads a source that is in svm light format.\n\n"
+ "For more information about svm light see:\n\n"
+ "http://svmlight.joachims.org/";
}
/**
* Get the file extension used for svm light files.
*
* @return the file extension
*/
public String getFileExtension() {
return FILE_EXTENSION;
}
/**
* Gets all the file extensions used for this type of file.
*
* @return the file extensions
*/
public String[] getFileExtensions() {
return new String[]{getFileExtension()};
}
/**
* Returns a description of the file type.
*
* @return a short file description
*/
public String getFileDescription() {
return "svm light data files";
}
/**
* Resets the Loader ready to read a new data set.
*
* @throws IOException if something goes wrong
*/
public void reset() throws IOException {
m_structure = null;
m_Buffer = null;
setRetrieval(NONE);
if (m_File != null) {
setFile(new File(m_File));
}
else if ((m_URL != null) && !m_URL.equals("http://")) {
setURL(m_URL);
}
}
/**
* Resets the Loader object and sets the source of the data set to be
* the supplied url.
*
* @param url the source url.
* @throws IOException if an error occurs
*/
public void setSource(URL url) throws IOException {
m_structure = null;
m_Buffer = null;
setRetrieval(NONE);
setSource(url.openStream());
m_URL = url.toString();
}
/**
* Set the url to load from.
*
* @param url the url to load from
* @throws IOException if the url can't be set.
*/
public void setURL(String url) throws IOException {
m_URL = url;
setSource(new URL(url));
}
/**
* Return the current url.
*
* @return the current url
*/
public String retrieveURL() {
return m_URL;
}
/**
* Resets the Loader object and sets the source of the data set to be
* the supplied InputStream.
*
* @param in the source InputStream.
* @throws IOException if initialization of reader fails.
*/
public void setSource(InputStream in) throws IOException {
m_File = (new File(System.getProperty("user.dir"))).getAbsolutePath();
m_URL = "http://";
m_sourceReader = new BufferedReader(new InputStreamReader(in));
}
/**
* turns a svm light row into a double array with the class as the last
* entry.
*
* @param row the row to turn into a double array
* @return the corresponding double array
* @throws Exception if a parsing error is encountered
*/
protected double[] svmlightToArray(String row) throws Exception {
double[] result;
StringTokenizer tok;
int index;
int max;
String col;
double value;
// actual data
try {
// determine max index
max = 0;
tok = new StringTokenizer(row, " \t");
tok.nextToken(); // skip class
while (tok.hasMoreTokens()) {
col = tok.nextToken();
// finished?
if (col.startsWith("#"))
break;
// qid is not supported
if (col.startsWith("qid:"))
continue;
// actual value
index = Integer.parseInt(col.substring(0, col.indexOf(":")));
if (index > max)
max = index;
}
// read values into array
tok = new StringTokenizer(row, " \t");
result = new double[max + 1];
// 1. class
result[result.length - 1] = Double.parseDouble(tok.nextToken());
// 2. attributes
while (tok.hasMoreTokens()) {
col = tok.nextToken();
// finished?
if (col.startsWith("#"))
break;
// qid is not supported
if (col.startsWith("qid:"))
continue;
// actual value
index = Integer.parseInt(col.substring(0, col.indexOf(":")));
value = Double.parseDouble(col.substring(col.indexOf(":") + 1));
result[index - 1] = value;
}
}
catch (Exception e) {
System.err.println("Error parsing line '" + row + "': " + e);
throw new Exception(e);
}
return result;
}
/**
* determines the number of attributes, if the number of attributes in the
* given row is greater than the current amount then this number will be
* returned, otherwise the current number.
*
* @param values the parsed values
* @param num the current number of attributes
* @return the new number of attributes
* @throws Exception if parsing fails
*/
protected int determineNumAttributes(double[] values, int num) throws Exception {
int result;
int count;
result = num;
count = values.length;
if (count > result)
result = count;
return result;
}
/**
* Determines the class attribute, either a binary +1/-1 or numeric attribute.
*
* @return the generated attribute
*/
protected Attribute determineClassAttribute() {
Attribute result;
boolean binary;
int i;
ArrayList<String> values;
double[] dbls;
double cls;
binary = true;
for (i = 0; i < m_Buffer.size(); i++) {
dbls = (double[]) m_Buffer.get(i);
cls = dbls[dbls.length - 1];
if ((cls != -1.0) && (cls != +1.0)) {
binary = false;
break;
}
}
if (binary) {
values = new ArrayList<String>();
values.add("+1");
values.add("-1");
result = new Attribute("class", values);
}
else {
result = new Attribute("class");
}
return result;
}
/**
* Determines and returns (if possible) the structure (internally the
* header) of the data set as an empty set of instances.
*
* @return the structure of the data set as an empty set
* of Instances
* @throws IOException if an error occurs
*/
public Instances getStructure() throws IOException {
StringBuffer line;
int cInt;
char c;
int numAtt;
ArrayList<Attribute> atts;
int i;
String relName;
if (m_sourceReader == null)
throw new IOException("No source has been specified");
if (m_structure == null) {
m_Buffer = new Vector<double[]>();
try {
// determine number of attributes
numAtt = 0;
line = new StringBuffer();
while ((cInt = m_sourceReader.read()) != -1) {
c = (char) cInt;
if ((c == '\n') || (c == '\r')) {
if ((line.length() > 0) && (line.charAt(0) != '#')) {
// actual data
try {
m_Buffer.add(svmlightToArray(line.toString()));
numAtt = determineNumAttributes((double[]) m_Buffer.lastElement(), numAtt);
}
catch (Exception e) {
throw new Exception("Error parsing line '" + line + "': " + e);
}
}
line = new StringBuffer();
}
else {
line.append(c);
}
}
// last line?
if ((line.length() != 0) && (line.charAt(0) != '#')) {
m_Buffer.add(svmlightToArray(line.toString()));
numAtt = determineNumAttributes((double[]) m_Buffer.lastElement(), numAtt);
}
// generate header
atts = new ArrayList<Attribute>(numAtt);
for (i = 0; i < numAtt - 1; i++)
atts.add(new Attribute("att_" + (i+1)));
atts.add(determineClassAttribute());
if (!m_URL.equals("http://"))
relName = m_URL;
else
relName = m_File;
m_structure = new Instances(relName, atts, 0);
m_structure.setClassIndex(m_structure.numAttributes() - 1);
}
catch (Exception ex) {
ex.printStackTrace();
throw new IOException("Unable to determine structure as svm light: " + ex);
}
}
return new Instances(m_structure, 0);
}
/**
* Return the full data set. If the structure hasn't yet been determined
* by a call to getStructure then method should do so before processing
* the rest of the data set.
*
* @return the structure of the data set as an empty
* set of Instances
* @throws IOException if there is no source or parsing fails
*/
public Instances getDataSet() throws IOException {
Instances result;
double[] sparse;
double[] data;
int i;
if (m_sourceReader == null)
throw new IOException("No source has been specified");
if (getRetrieval() == INCREMENTAL)
throw new IOException("Cannot mix getting Instances in both incremental and batch modes");
setRetrieval(BATCH);
if (m_structure == null)
getStructure();
result = new Instances(m_structure, 0);
// create instances from buffered arrays
for (i = 0; i < m_Buffer.size(); i++) {
sparse = (double[]) m_Buffer.get(i);
if (sparse.length != m_structure.numAttributes()) {
data = new double[m_structure.numAttributes()];
// attributes
System.arraycopy(sparse, 0, data, 0, sparse.length - 1);
// class
data[data.length - 1] = sparse[sparse.length - 1];
}
else {
data = sparse;
}
// fix class
if (result.classAttribute().isNominal()) {
if (data[data.length - 1] == 1.0)
data[data.length - 1] = result.classAttribute().indexOfValue("+1");
else if (data[data.length - 1] == -1)
data[data.length - 1] = result.classAttribute().indexOfValue("-1");
else
throw new IllegalStateException("Class is not binary!");
}
result.add(new SparseInstance(1, data));
}
try {
// close the stream
m_sourceReader.close();
} catch (Exception ex) {
}
return result;
}
/**
* SVMLightLoader is unable to process a data set incrementally.
*
* @param structure ignored
* @return never returns without throwing an exception
* @throws IOException always. SVMLightLoader is unable to process a
* data set incrementally.
*/
public Instance getNextInstance(Instances structure) throws IOException {
throw new IOException("SVMLightLoader can't read data sets incrementally.");
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 5953 $");
}
/**
* Main method.
*
* @param args should contain the name of an input file.
*/
public static void main(String[] args) {
runFileLoader(new SVMLightLoader(), args);
}
}