/*
* ARX: Powerful Data Anonymization
* Copyright 2012 - 2017 Fabian Prasser, Florian Kohlmayer and contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.deidentifier.arx.metric.v2;
import org.deidentifier.arx.ARXConfiguration;
import org.deidentifier.arx.certificate.elements.ElementData;
import org.deidentifier.arx.framework.check.groupify.HashGroupify;
import org.deidentifier.arx.framework.check.groupify.HashGroupifyEntry;
import org.deidentifier.arx.framework.lattice.Transformation;
import org.deidentifier.arx.metric.MetricConfiguration;
/**
* This class provides an implementation of the non-monotonic DM metric.
* TODO: Add reference
*
* @author Fabian Prasser
* @author Florian Kohlmayer
*/
public class MetricSDNMDiscernability extends AbstractMetricSingleDimensional {
/** SVUID. */
private static final long serialVersionUID = -8573084860566655278L;
/**
* Creates a new instance.
*/
protected MetricSDNMDiscernability() {
super(true, false, false);
}
/**
* For subclasses.
*
* @param monotonicWithGeneralization
* @param monotonicWithSuppression
*/
MetricSDNMDiscernability(boolean monotonicWithGeneralization, boolean monotonicWithSuppression) {
super(monotonicWithGeneralization, monotonicWithSuppression, false);
}
@Override
public ILSingleDimensional createMaxInformationLoss() {
Double rows = getNumTuples();
if (rows == null) {
throw new IllegalStateException("Metric must be initialized first");
} else {
return new ILSingleDimensional(rows * rows);
}
}
@Override
public ILSingleDimensional createMinInformationLoss() {
Double rows = getNumTuples();
if (rows == null) {
throw new IllegalStateException("Metric must be initialized first");
} else {
return new ILSingleDimensional(rows);
}
}
/**
* Returns the configuration of this metric.
*
* @return
*/
public MetricConfiguration getConfiguration() {
return new MetricConfiguration(false, // monotonic
0.5d, // gs-factor
false, // precomputed
0.0d, // precomputation threshold
AggregateFunction.SUM // aggregate function
);
}
@Override
public ElementData render(ARXConfiguration config) {
ElementData result = new ElementData("Discernibility");
result.addProperty("Monotonic", this.isMonotonic(config.getMaxOutliers()));
return result;
}
@Override
public String toString() {
return "Non-monotonic discernability";
}
@Override
protected ILSingleDimensionalWithBound getInformationLossInternal(final Transformation node, final HashGroupify g) {
double rows = getNumTuples();
double dm = 0;
double dmStar = 0;
HashGroupifyEntry m = g.getFirstEquivalenceClass();
while (m != null) {
if (m.count>0){
double count = (double)m.count;
double current = count * count;
dmStar += current;
dm += m.isNotOutlier ? current : rows * count;
}
m = m.nextOrdered;
}
return new ILSingleDimensionalWithBound(dm, dmStar);
}
@Override
protected ILSingleDimensionalWithBound getInformationLossInternal(Transformation node, HashGroupifyEntry entry) {
return new ILSingleDimensionalWithBound(entry.count);
}
@Override
protected ILSingleDimensional getLowerBoundInternal(Transformation node) {
return null;
}
@Override
protected ILSingleDimensional getLowerBoundInternal(Transformation node,
HashGroupify groupify) {
double lowerBound = 0;
HashGroupifyEntry m = groupify.getFirstEquivalenceClass();
while (m != null) {
lowerBound += (m.count>0) ? ((double) m.count * (double) m.count) : 0;
m = m.nextOrdered;
}
return new ILSingleDimensional(lowerBound);
}
}