/*
* RapidMiner
*
* Copyright (C) 2001-2011 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.features.selection;
import java.util.Iterator;
import java.util.List;
import java.util.Vector;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeWeights;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.MetaData;
import com.rapidminer.operator.preprocessing.AbstractDataProcessing;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeBoolean;
import com.rapidminer.parameter.ParameterTypeCategory;
import com.rapidminer.parameter.ParameterTypeDouble;
import com.rapidminer.parameter.ParameterTypeInt;
import com.rapidminer.parameter.conditions.EqualTypeCondition;
/**
* This operator selects all attributes which have a weight satisfying a given
* condition. For example, only attributes with a weight greater than
* <code>min_weight</code> should be selected. This operator is also able
* to select the k attributes with the highest weight.
*
* @author Ingo Mierswa, Stefan Rueping
*/
public class AttributeWeightSelection extends AbstractDataProcessing {
/** The parameter name for "Use this weight for the selection relation." */
public static final String PARAMETER_WEIGHT = "weight";
/** The parameter name for "Selects only weights which fulfill this relation." */
public static final String PARAMETER_WEIGHT_RELATION = "weight_relation";
/** The parameter name for "Number k of attributes to be selected for weight-relations 'top k' or 'bottom k'." */
public static final String PARAMETER_K = "k";
/** The parameter name for "Percentage of attributes to be selected for weight-relations 'top p%' or 'bottom p%'." */
public static final String PARAMETER_P = "p";
/** The parameter name for "Indicates if attributes which weight is unknown should be deselected." */
public static final String PARAMETER_DESELECT_UNKNOWN = "deselect_unknown";
/** The parameter name for "Indicates if the absolute values of the weights should be used for comparison." */
public static final String PARAMETER_USE_ABSOLUTE_WEIGHTS = "use_absolute_weights";
private static final String[] WEIGHT_RELATIONS = { "greater", "greater equals", "equals", "less equals", "less", "top k", "bottom k", "all but top k", "all but bottom k", "top p%", "bottom p%" };
private static final int GREATER = 0;
private static final int GREATER_EQUALS = 1;
private static final int EQUALS = 2;
private static final int LESS_EQUALS = 3;
private static final int LESS = 4;
private static final int TOPK = 5;
private static final int BOTTOMK = 6;
private static final int ALLBUTTOPK = 7;
private static final int ALLBUTBOTTOMK = 8;
private static final int TOPPPERCENT = 9;
private static final int BOTTOMPPERCENT = 10;
private InputPort weightsInput = getInputPorts().createPort("weights", AttributeWeights.class);
private OutputPort weightsOutput = getOutputPorts().createPort("weights");
public AttributeWeightSelection(OperatorDescription description) {
super(description);
getTransformer().addPassThroughRule(weightsInput, weightsOutput);
}
@Override
protected MetaData modifyMetaData(ExampleSetMetaData metaData) {
metaData.attributesAreSubset();
return metaData;
}
@Override
public ExampleSet apply(ExampleSet exampleSet) throws OperatorException {
AttributeWeights weights = weightsInput.getData();
boolean deselectUnknown = getParameterAsBoolean(PARAMETER_DESELECT_UNKNOWN);
double relationWeight = getParameterAsDouble(PARAMETER_WEIGHT);
int relation = getParameterAsInt(PARAMETER_WEIGHT_RELATION);
boolean useAbsoluteWeights = getParameterAsBoolean(PARAMETER_USE_ABSOLUTE_WEIGHTS);
// determine which attributes have a known weight value
boolean[] weightKnown = new boolean[exampleSet.getAttributes().size()];
Vector<Attribute> knownAttributes = new Vector<Attribute>();
int index = 0;
for (Attribute attribute : exampleSet.getAttributes()) {
double weight = weights.getWeight(attribute.getName());
if (!Double.isNaN(weight)) {
knownAttributes.add(attribute);
weightKnown[index++] = true;
} else {
weightKnown[index++] = false;
}
}
// determine number of attributes that should be selected
int nrAtts = knownAttributes.size();
int k = getParameterAsInt(PARAMETER_K);
if (relation == ALLBUTTOPK) {
relation = BOTTOMK;
k = nrAtts - k;
}
if (relation == ALLBUTBOTTOMK) {
relation = TOPK;
k = nrAtts - k;
}
if (relation == TOPPPERCENT) {
relation = TOPK;
k = (int) Math.round(nrAtts * getParameterAsDouble(PARAMETER_P));
}
if (relation == BOTTOMPPERCENT) {
relation = BOTTOMK;
k = (int) Math.round(nrAtts * getParameterAsDouble(PARAMETER_P));
}
if (k < 1)
k = 1;
if (k > nrAtts)
k = nrAtts;
// top k or bottom k
if ((relation == TOPK) || (relation == BOTTOMK)) {
int direction = AttributeWeights.DECREASING;
if (relation == BOTTOMK)
direction = AttributeWeights.INCREASING;
int comparatorType = AttributeWeights.ORIGINAL_WEIGHTS;
if (useAbsoluteWeights)
comparatorType = AttributeWeights.ABSOLUTE_WEIGHTS;
String[] attributeNames = new String[knownAttributes.size()];
index = 0;
for (Attribute attribute : knownAttributes) {
attributeNames[index++] = attribute.getName();
}
weights.sortByWeight(attributeNames, direction, comparatorType);
Iterator<Attribute> iterator = exampleSet.getAttributes().iterator();
index = 0;
while (iterator.hasNext()) {
Attribute attribute = iterator.next();
if (!weightKnown[index]) {
if (deselectUnknown) {
iterator.remove();
}
} else {
boolean remove = true;
for (int i = 0; i < k; i++) {
if (attribute.getName().equals(attributeNames[i])) {
remove = false;
break;
}
}
if (remove)
iterator.remove();
}
index++;
}
} else { // simple relations
Iterator<Attribute> iterator = exampleSet.getAttributes().iterator();
while (iterator.hasNext()) {
Attribute attribute = iterator.next();
double weight = weights.getWeight(attribute.getName());
if (useAbsoluteWeights)
weight = Math.abs(weight);
if (Double.isNaN(weight) && (deselectUnknown)) {
iterator.remove();
} else {
switch (relation) {
case GREATER:
if (weight <= relationWeight)
iterator.remove();
break;
case GREATER_EQUALS:
if (weight < relationWeight)
iterator.remove();
break;
case EQUALS:
if (weight != relationWeight)
iterator.remove();
break;
case LESS_EQUALS:
if (weight > relationWeight)
iterator.remove();
break;
case LESS:
if (weight >= relationWeight)
iterator.remove();
break;
}
}
}
}
weightsOutput.deliver(weights);
return exampleSet;
}
@Override
public boolean shouldAutoConnect(OutputPort port) {
if (port == weightsOutput) {
return getParameterAsBoolean("keep_attribute_weights");
} else {
return super.shouldAutoConnect(port);
}
}
@Override
public List<ParameterType> getParameterTypes() {
List<ParameterType> types = super.getParameterTypes();
ParameterType type = new ParameterTypeCategory(PARAMETER_WEIGHT_RELATION, "Selects only weights which fulfill this relation.", WEIGHT_RELATIONS, GREATER_EQUALS);
type.setExpert(false);
types.add(type);
type = new ParameterTypeDouble(PARAMETER_WEIGHT, "The selected relation will be evaluated against this value.", Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, 1.0d);
type.registerDependencyCondition(new EqualTypeCondition(this, PARAMETER_WEIGHT_RELATION, WEIGHT_RELATIONS, true, GREATER, GREATER_EQUALS, LESS, LESS_EQUALS, EQUALS));
type.setExpert(false);
types.add(type);
type = new ParameterTypeInt(PARAMETER_K, "Number k of attributes to be selected. For example 'top k' with k = 5 will return an exampleset containing only the 5 highest weighted attributes.", 1, Integer.MAX_VALUE, 10);
type.registerDependencyCondition(new EqualTypeCondition(this, PARAMETER_WEIGHT_RELATION, WEIGHT_RELATIONS, true, TOPK, BOTTOMK, ALLBUTBOTTOMK, ALLBUTTOPK));
type.setExpert(false);
types.add(type);
type = new ParameterTypeDouble(PARAMETER_P, "Percentage of attributes to be selected. For example 'top p%' with p = 15 will return an exampleset containing only attributes which are part of the 15% of the highest weighted attributes.", 0.0d, 1.0d, 0.5d);
type.registerDependencyCondition(new EqualTypeCondition(this, PARAMETER_WEIGHT_RELATION, WEIGHT_RELATIONS, true, TOPPPERCENT, BOTTOMPPERCENT));
type.setExpert(false);
types.add(type);
types.add(new ParameterTypeBoolean(PARAMETER_DESELECT_UNKNOWN, "Indicates if attributes which weight is unknown should be removed from example set.", true));
types.add(new ParameterTypeBoolean(PARAMETER_USE_ABSOLUTE_WEIGHTS, "Indicates if the absolute values of the weights should be used for comparison.", true));
return types;
}
@Override
public boolean writesIntoExistingData() {
return false;
}
}