content: /*
   *    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.
   */
  
  /*
   *    AddExpression.java
   *    Copyright (C) 2000 University of Waikato, Hamilton, New Zealand
   *
   */
  
  package weka.filters.unsupervised.attribute;
  
  import weka.core.Attribute;
  import weka.core.AttributeExpression;
  import weka.core.Capabilities;
  import weka.core.Instance; 
  import weka.core.DenseInstance;
  import weka.core.Instances;
  import weka.core.Option;
  import weka.core.OptionHandler;
  import weka.core.RevisionUtils;
  import weka.core.SparseInstance;
  import weka.core.Utils;
  import weka.core.Capabilities.Capability;
  import weka.filters.Filter;
  import weka.filters.StreamableFilter;
  import weka.filters.UnsupervisedFilter;
  
  import java.util.Enumeration;
  import java.util.Vector;
  
  /**
   <!-- globalinfo-start -->
   * An instance filter that creates a new attribute by applying a mathematical expression to existing attributes. The expression can contain attribute references and numeric constants. Supported operators are :<br/>
   * +, -, *, /, ^, log, abs, cos, exp, sqrt, floor, ceil, rint, tan, sin, (, )<br/>
   * Attributes are specified by prefixing with 'a', eg. a7 is attribute number 7 (starting from 1).<br/>
   * Example expression : a1^2*a5/log(a7*4.0).
   * <p/>
   <!-- globalinfo-end -->
   * 
   <!-- options-start -->
   * Valid options are: <p/>
   * 
   * <pre> -E &lt;expression&gt;
   *  Specify the expression to apply. Eg a1^2*a5/log(a7*4.0).
   *  Supported opperators: ,+, -, *, /, ^, log, abs, cos, 
   *  exp, sqrt, floor, ceil, rint, tan, sin, (, )
   *  (default: a1^2)</pre>
   * 
   * <pre> -N &lt;name&gt;
   *  Specify the name for the new attribute. (default is the expression provided with -E)</pre>
   * 
   * <pre> -D
   *  Debug. Names attribute with the postfix parse of the expression.</pre>
   * 
   <!-- options-end -->
   *
   * @author Mark Hall (mhall@cs.waikato.ac.nz)
   * @version $Revision: 5987 $
   */
  public class AddExpression 
    extends Filter 
    implements UnsupervisedFilter, StreamableFilter, OptionHandler {
  
    /** for serialization */
    static final long serialVersionUID = 402130384261736245L;
    
    /** The infix expression */
    private String m_infixExpression = "a1^2";
  
    /** Name of the new attribute. "expression"  length string will use the 
        provided expression as the new attribute name */
    private String m_attributeName="expression";
  
    /** If true, makes the attribute name equal to the postfix parse of the
        expression */
    private boolean m_Debug = false;
  
    private AttributeExpression m_attributeExpression = null;
  
    /**
     * Returns a string describing this filter
     *
     * @return 		a description of the filter suitable for
     * 			displaying in the explorer/experimenter gui
     */
    public String globalInfo() {
      return 
          "An instance filter that creates a new attribute by applying a "
        + "mathematical expression to existing attributes. The expression "
        + "can contain attribute references and numeric constants. Supported "
        + "operators are :\n"
        + "+, -, *, /, ^, log, abs, cos, exp, sqrt, floor, ceil, rint, tan, "
        + "sin, (, )\n"
        + "Attributes are specified by prefixing with 'a', eg. a7 is "
        + "attribute number 7 (starting from 1).\n"
        + "Example expression : a1^2*a5/log(a7*4.0).";
    }
    
    /**
     * Returns an enumeration describing the available options.
     *
     * @return an enumeration of all the available options.
     */
    public Enumeration listOptions() {
  
      Vector newVector = new Vector(3); 
  
      newVector.addElement(new Option(
  	     "\tSpecify the expression to apply. Eg a1^2*a5/log(a7*4.0)."
  	     +"\n\tSupported opperators: ,+, -, *, /, ^, log, abs, cos, "
  	     +"\n\texp, sqrt, floor, ceil, rint, tan, sin, (, )"
  	     +"\n\t(default: a1^2)",
  	     "E",1,"-E <expression>"));
  
      newVector.addElement(new Option(
  	     "\tSpecify the name for the new attribute. (default is the "
  	     +"expression provided with -E)",
  	     "N",1,"-N <name>"));
  
      newVector.addElement(new Option(
  	     "\tDebug. Names attribute with the postfix parse of the "
  	     +"expression.","D",0,"-D"));
  
      return newVector.elements();
    }
  
    /**
     * Parses a given list of options. <p/>
     * 
     <!-- options-start -->
     * Valid options are: <p/>
     * 
     * <pre> -E &lt;expression&gt;
     *  Specify the expression to apply. Eg a1^2*a5/log(a7*4.0).
     *  Supported opperators: ,+, -, *, /, ^, log, abs, cos, 
     *  exp, sqrt, floor, ceil, rint, tan, sin, (, )
     *  (default: a1^2)</pre>
     * 
     * <pre> -N &lt;name&gt;
     *  Specify the name for the new attribute. (default is the expression provided with -E)</pre>
     * 
     * <pre> -D
     *  Debug. Names attribute with the postfix parse of the expression.</pre>
     * 
     <!-- options-end -->
     *
     * @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 {
      String expString = Utils.getOption('E', options);
      if (expString.length() != 0) {
        setExpression(expString);
      } else {
        setExpression("a1^2");
      }
  
      String name = Utils.getOption('N',options);
      if (name.length() != 0) {
        setName(name);
      }
  
      setDebug(Utils.getFlag('D', options));
    }
    
    /**
     * Gets the current settings of the filter.
     *
     * @return an array of strings suitable for passing to setOptions
     */
    public String [] getOptions() {
  
      String [] options = new String [5];
      int current = 0;
      
      options[current++] = "-E"; options[current++] = getExpression();
      options[current++] = "-N"; options[current++] = getName();
  
      if (getDebug()) {
        options[current++] = "-D";
      }
      
      while (current < options.length) {
        options[current++] = "";
      }
      return options;
    }
  
    /**
     * Returns the tip text for this property
     *
     * @return tip text for this property suitable for
     * displaying in the explorer/experimenter gui
     */
    public String nameTipText() {
      return "Set the name of the new attribute.";
    }
  
    /**
     * Set the name for the new attribute. The string "expression" can
     * be used to make the name of the new attribute equal to the expression
     * provided.
     * @param name the name of the new attribute
     */
    public void setName(String name) {
      m_attributeName = name;
    }
  
    /**
     * Returns the name of the new attribute
     * @return the name of the new attribute
     */
    public String getName() {
      return m_attributeName;
    }
  
    /**
     * 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 "Set debug mode. If true then the new attribute will be named with "
        +"the postfix parse of the supplied expression.";
    }
    
    /**
     * Set debug mode. Causes the new attribute to be named with the postfix
     * parse of the expression
     * @param d true if debug mode is to be used
     */
    public void setDebug(boolean d) {
      m_Debug = d;
    }
  
    /**
     * Gets whether debug is set
     * @return true if debug is set
     */
    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 expressionTipText() {
      return "Set the math expression to apply. Eg. a1^2*a5/log(a7*4.0)";
    }
  
    /**
     * Set the expression to apply
     * @param expr a mathematical expression to apply
     */
    public void setExpression(String expr) {
      m_infixExpression = expr;
    }
  
    /**
     * Get the expression
     * @return the expression
     */
    public String getExpression() {
      return m_infixExpression;
    }
  
    /** 
     * Returns the Capabilities of this filter.
     *
     * @return            the capabilities of this object
     * @see               Capabilities
     */
    public Capabilities getCapabilities() {
      Capabilities result = super.getCapabilities();
      result.disableAll();
  
      // attributes
      result.enableAllAttributes();
      result.enable(Capability.MISSING_VALUES);
      
      // class
      result.enableAllClasses();
      result.enable(Capability.MISSING_CLASS_VALUES);
      result.enable(Capability.NO_CLASS);
      
      return result;
    }
  
    /**
     * Sets the format of the input instances.
     *
     * @param instanceInfo an Instances object containing the input instance
     * structure (any instances contained in the object are ignored - only the
     * structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws Exception if the format couldn't be set successfully
     */
    public boolean setInputFormat(Instances instanceInfo) throws Exception {
  
      m_attributeExpression = new AttributeExpression();
      m_attributeExpression.
        convertInfixToPostfix(new String(m_infixExpression));
  
      super.setInputFormat(instanceInfo);
  
      Instances outputFormat = new Instances(instanceInfo, 0);
      Attribute newAttribute;
      if (m_Debug) {
        newAttribute = 
          new Attribute(m_attributeExpression.getPostFixExpression());
      } else if (m_attributeName.compareTo("expression") != 0) {
        newAttribute = new Attribute(m_attributeName);
      } else {
        newAttribute = new Attribute(m_infixExpression);
      }
      outputFormat.insertAttributeAt(newAttribute, 
  				   instanceInfo.numAttributes());
      setOutputFormat(outputFormat);
      return true;
    }
  
    /**
     * Input an instance for filtering. Ordinarily the instance is processed
     * and made available for output immediately. Some filters require all
     * instances be read before producing output.
     *
     * @param instance the input instance
     * @return true if the filtered instance may now be
     * collected with output().
     * @throws IllegalStateException if no input format has been defined.
     * @throws Exception if there was a problem during the filtering.
     */
    public boolean input(Instance instance) throws Exception {
  
      if (getInputFormat() == null) {
        throw new IllegalStateException("No input instance format defined");
      }
      if (m_NewBatch) {
        resetQueue();
        m_NewBatch = false;
      }
  
      double[] vals = new double[instance.numAttributes()+1];
      for(int i = 0; i < instance.numAttributes(); i++) {
        if (instance.isMissing(i)) {
  	vals[i] = Utils.missingValue();
        } else {
  	vals[i] = instance.value(i);
        }
      }
  
      m_attributeExpression.evaluateExpression(vals);
  
      Instance inst = null;
      if (instance instanceof SparseInstance) {
        inst = new SparseInstance(instance.weight(), vals);
      } else {
        inst = new DenseInstance(instance.weight(), vals);
      }
  
      inst.setDataset(getOutputFormat());
      copyValues(inst, false, instance.dataset(), getOutputFormat());
      inst.setDataset(getOutputFormat());
      push(inst);
      return true;
    }
    
    /**
     * Returns the revision string.
     * 
     * @return		the revision
     */
    public String getRevision() {
      return RevisionUtils.extract("$Revision: 5987 $");
    }
    
    /**
     * Main method for testing this class.
     *
     * @param args should contain arguments to the filter: use -h for help
     */
    public static void main(String [] args) {
      runFilter(new AddExpression(), args);
    }
  }
  