/*
* 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 <expression>
* 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 <name>
* 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 <expression>
* 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 <name>
* 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);
}
}