/*
* 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.risk;
import java.util.Arrays;
import org.deidentifier.arx.ARXConfiguration;
/**
* Class representing the distribution of risks in the sample
*
* @author Fabian Prasser
*/
public class RiskModelSampleRiskDistribution {
/** Thresholds */
private static final double[] thresholdsLow = new double[] { 0d,
0.00000001d,
0.0000001d,
0.000001d,
0.00001d,
0.0001d,
0.001d,
0.01d,
0.02d,
0.03d,
0.04d,
0.05d,
0.06d,
0.07d,
0.08d,
0.09d,
0.1d,
0.125d,
0.143d,
0.167d,
0.2d,
0.25d,
0.334d,
0.5d};
/** Thresholds */
private static final double[] thresholdsHigh = new double[] { 0.00000001d,
0.0000001d,
0.000001d,
0.00001d,
0.0001d,
0.001d,
0.01d,
0.02d,
0.03d,
0.04d,
0.05d,
0.06d,
0.07d,
0.08d,
0.09d,
0.1d,
0.125d,
0.143d,
0.167d,
0.2d,
0.25d,
0.334d,
0.5d,
1d };
/** Risks */
private final double[] recordsAtRisk = new double[thresholdsLow.length];
/** Cumulative risks */
private final double[] recordsAtCumulativeRisk = new double[thresholdsLow.length];
/** Threshold risk */
private final double threshold;
/**
* Creates a new instance
*
* @param histogram
* @param config
* @param anonymous
*/
public RiskModelSampleRiskDistribution(RiskModelHistogram histogram,
ARXConfiguration config,
boolean anonymous) {
int[] array = histogram.getHistogram();
for (int i = 0; i < array.length; i += 2) {
int size = array[i];
int count = array[i+1];
double risk = 1d / (double)size;
double records = (double)(count * size)/ histogram.getNumRecords();
int index = Arrays.binarySearch(thresholdsHigh, risk);
if (index < 0) {
index = -index - 1;
}
this.recordsAtRisk[index] += records;
}
double cumulativeRisk = 0;
for (int i=0; i<thresholdsHigh.length; i++) {
cumulativeRisk += this.recordsAtRisk[i];
this.recordsAtCumulativeRisk[i] = cumulativeRisk;
}
this.threshold = Math.min(1.0d / (double)histogram.getHistogram()[0], config != null && anonymous ? config.getRiskThresholdProsecutor() : 1d);
}
/**
* Returns the lower bounds (exclusive) of the intervals for the according data points.
*
* @return
*/
public double[] getAvailableLowerRiskThresholds() {
return thresholdsLow;
}
/**
* Returns the lower bounds (inclusive) of the intervals for the according data points.
*
* @return
*/
public double[] getAvailableUpperRiskThresholds() {
return thresholdsHigh;
}
/**
* Returns the fraction of records with a risk lower than or equal
* to the given threshold.
*
* @param risk
* @return
*/
public double getFractionOfRecordsAtCumulativeRisk(double risk) {
if (risk < 0d || risk >1d) {
throw new IllegalArgumentException("Parameter out of range [0, 1]: " + risk);
}
int index = Arrays.binarySearch(thresholdsHigh, risk);
if (index < 0) {
index = -index - 1;
}
return recordsAtCumulativeRisk[index];
}
/**
* Returns the fraction of records with a risk which equals the given threshold.
*
* @param risk
* @return
*/
public double getFractionOfRecordsAtRisk(double risk) {
if (risk < 0d || risk >1d) {
throw new IllegalArgumentException("Parameter out of range [0, 1]: " + risk);
}
int index = Arrays.binarySearch(thresholdsHigh, risk);
if (index < 0) {
index = -index - 1;
}
return recordsAtRisk[index];
}
/**
* Returns an array of cumulative risks for the risk thresholds
* @return
*/
public double[] getFractionOfRecordsForCumulativeRiskThresholds() {
return recordsAtCumulativeRisk;
}
/**
* Returns an array of risks for the risk thresholds
* @return
*/
public double[] getFractionOfRecordsForRiskThresholds() {
return recordsAtRisk;
}
/**
* Returns the threshold for which is available on prosecutor risks
* @return
*/
public double getRiskThreshold() {
return this.threshold;
}
}