csvloader.java

矩阵的QR分解算法

				      atts, 
				      m_cumulativeInstances.size());

    for (int i = 0; i < m_cumulativeInstances.size(); i++) {
      current = ((FastVector)m_cumulativeInstances.elementAt(i));
      double [] vals = new double[dataSet.numAttributes()];
      for (int j = 0; j < current.size(); j++) {
	Object cval = current.elementAt(j);
	if (cval instanceof String) {
	  if (((String)cval).compareTo("'?'") == 0) {
	    vals[j] = Instance.missingValue();
	  } else {
	    if (!dataSet.attribute(j).isNominal()) {
	      System.err.println("Wrong attribute type!!!");
	      System.exit(1);
	    }
	    // find correct index
	    Hashtable lookup = (Hashtable)m_cumulativeStructure.elementAt(j);
	    int index = ((Integer)lookup.get(cval)).intValue();
	    vals[j] = (double)index;
	  }
	} else if (dataSet.attribute(j).isNominal()) {
	  // find correct index
	  Hashtable lookup = (Hashtable)m_cumulativeStructure.elementAt(j);
	  int index = ((Integer)lookup.get(cval)).intValue();
	  vals[j] = (double)index;
	} else {
	  vals[j] = ((Double)cval).doubleValue();
	}
      }
      dataSet.add(new Instance(1.0, vals));
    }
    m_structure = new Instances(dataSet, 0);
    setRetrieval(BATCH);
    m_cumulativeStructure = null; // conserve memory
    return dataSet;
  }

  /**
   * CSVLoader is unable to process a data set incrementally.
   *
   * @param structure ignored
   * @return never returns without throwing an exception
   * @exception IOException always. CSVLoader is unable to process a data
   * set incrementally.
   */
  public Instance getNextInstance(Instances structure) throws IOException {
    throw new IOException("CSVLoader can't read data sets incrementally.");
  }

  /**
   * Attempts to parse a line of the data set.
   *
   * @param tokenizer the tokenizer
   * @return a FastVector containg String and Double objects representing
   * the values of the instance.
   * @exception IOException if an error occurs
   *
   * <pre><jml>
   *    private_normal_behavior
   *      requires: tokenizer != null;
   *      ensures: \result  != null;
   *  also
   *    private_exceptional_behavior
   *      requires: tokenizer == null
   *                || (* unsucessful parse *);
   *      signals: (IOException);
   * </jml></pre>
   */
  private FastVector getInstance(StreamTokenizer tokenizer) 
    throws IOException {

    FastVector current = new FastVector();

    // Check if end of file reached.
    ConverterUtils.getFirstToken(tokenizer);
    if (tokenizer.ttype == StreamTokenizer.TT_EOF) {
      return null;
    }
    boolean first = true;
    boolean wasSep;

    while (tokenizer.ttype != StreamTokenizer.TT_EOL &&
	   tokenizer.ttype != StreamTokenizer.TT_EOF) {
      
      // Get next token
      if (!first) {
	ConverterUtils.getToken(tokenizer);
      }

      if (tokenizer.ttype == ',' || tokenizer.ttype == '\t' || 
	  tokenizer.ttype == StreamTokenizer.TT_EOL) {
	current.addElement("?");
	wasSep = true;
      } else if (tokenizer.ttype == '?') {
        wasSep = false;
        current.addElement(new String("'?'"));
      } else {
	wasSep = false;
	// try to parse as a number
	try {
	  double val = Double.valueOf(tokenizer.sval).doubleValue();
	  current.addElement(new Double(val));
	} catch (NumberFormatException e) {
	  // otherwise assume its an enumerated value
	  current.addElement(new String(tokenizer.sval));
	}
      }
      
      if (!wasSep) {
	ConverterUtils.getToken(tokenizer);
      }
      first = false;
    }
    
    // check number of values read
    if (current.size() != m_structure.numAttributes()) {
      ConverterUtils.errms(tokenizer, 
			   "wrong number of values. Read "+current.size()
			   +", expected "+m_structure.numAttributes());
    }

    // check for structure update
    try {
      checkStructure(current);
    } catch (Exception ex) {
      ex.printStackTrace();
    }

    return current;
  }

  /**
   * Checks the current instance against what is known about the structure
   * of the data set so far. If there is a nominal value for an attribute
   * that was beleived to be numeric then all previously seen values for this
   * attribute are stored in a Hashtable.
   *
   * @param current a <code>FastVector</code> value
   * @exception Exception if an error occurs
   *
   * <pre><jml>
   *    private_normal_behavior
   *      requires: current != null;
   *  also
   *    private_exceptional_behavior
   *      requires: current == null
   *                || (* unrecognized object type in current *);
   *      signals: (Exception);
   * </jml></pre>
   */
  private void checkStructure(FastVector current) throws Exception {
    if (current == null) {
      throw new Exception("current shouldn't be null in checkStructure");
    }
    for (int i = 0; i < current.size(); i++) {
      Object ob = current.elementAt(i);
      if (ob instanceof String) {
	if (((String)ob).compareTo("'?'") == 0) {
	} else {
	  Hashtable tempHash = (Hashtable)m_cumulativeStructure.elementAt(i);
	  if (!tempHash.containsKey(ob)) {
	    // may have found a nominal value in what was previously thought to
	    // be a numeric variable.
	    if (tempHash.size() == 0) {
	      for (int j = 0; j < m_cumulativeInstances.size(); j++) {
		FastVector tempUpdate = 
		  ((FastVector)m_cumulativeInstances.elementAt(j));
		Object tempO = tempUpdate.elementAt(i);
		if (tempO instanceof String) {
		  // must have been a missing value
		} else {
		  if (!tempHash.containsKey(tempO)) {
		    tempHash.put(new Double(((Double)tempO).doubleValue()), 
				 new Integer(tempHash.size()));
		  }
		}
	      }
	    }
	    int newIndex = tempHash.size();
	    tempHash.put(ob, new Integer(newIndex));
	  }
	}
      } else if (ob instanceof Double) {
	Hashtable tempHash = (Hashtable)m_cumulativeStructure.elementAt(i);
	if (tempHash.size() != 0) {
	  if (!tempHash.containsKey(ob)) {
	    int newIndex = tempHash.size();
	    tempHash.put(new Double(((Double)ob).doubleValue()), 
				    new Integer(newIndex));
	  }
	}
      } else {
	throw new Exception("Wrong object type in checkStructure!");
      }
    }
  }

  /**
   * Assumes the first line of the file contains the attribute names.
   * Assumes all attributes are real (Reading the full data set with
   * getDataSet will establish the true structure).
   *
   * @param tokenizer a <code>StreamTokenizer</code> value
   * @exception IOException if an error occurs
   *
   * <pre><jml>
   *    private_normal_behavior
   *      requires: tokenizer != null;
   *      modifiable: m_structure;
   *      ensures: m_structure != null;
   *  also
   *    private_exceptional_behavior
   *      requires: tokenizer == null
   *                || (* unsucessful parse *);
   *      signals: (IOException);
   * </jml></pre>
   */
  private void readHeader(StreamTokenizer tokenizer) throws IOException {
   
    FastVector attribNames = new FastVector();
    ConverterUtils.getFirstToken(tokenizer);
    if (tokenizer.ttype == StreamTokenizer.TT_EOF) {
      ConverterUtils.errms(tokenizer,"premature end of file");
    }

    while (tokenizer.ttype != StreamTokenizer.TT_EOL) {
      attribNames.addElement(new Attribute(tokenizer.sval));
      ConverterUtils.getToken(tokenizer);
    }
    String relationName;
    if (m_sourceFile != null)
      relationName = (m_sourceFile.getName()).replaceAll("\\.[cC][sS][vV]$","");
    else
      relationName = "stream";
    m_structure = new Instances(relationName, attribNames, 0);
  }

  /**
   * Initializes the stream tokenizer
   *
   * @param tokenizer the tokenizer to initialize
   */
  private void initTokenizer(StreamTokenizer tokenizer) {
    tokenizer.resetSyntax();         
    tokenizer.whitespaceChars(0, (' '-1));    
    tokenizer.wordChars(' ','\u00FF');
    tokenizer.whitespaceChars(',',',');
    tokenizer.whitespaceChars('\t','\t');
    tokenizer.commentChar('%');
    tokenizer.quoteChar('"');
    tokenizer.quoteChar('\'');
    tokenizer.eolIsSignificant(true);
  }

  /**
   * Main method.
   *
   * @param args should contain the name of an input file.
   */
  public static void main(String [] args) {
    runFileLoader(new CSVLoader(), args);
  }
}