work in progress

contribs/drt/src/main/java/org/matsim/contrib/drt/estimator/impl/EuclideanDistanceBasedDrtEstimator.java

@@ -47,8 +47,8 @@ public EuclideanDistanceBasedDrtEstimator(Network network, double networkDistanc
 		this.networkDistanceFactor = networkDistanceFactor;
 		this.tripEstimator = new ConstantTripEstimator(slope, intercept);
 		this.waitingTimeEstimator = new ConstantWaitingTimeEstimator(estimatedMeanWaitTime);
-		this.rideDurationDistributionGenerator = new LogNormalDistributionGenerator(new Random(4711), mu, sigma);
-		this.waitingTimeDistributionGenerator = new NormalDistributionGenerator(4711, waitTimeStd);
+		this.rideDurationDistributionGenerator = new LogNormalDistributionGenerator(1, mu, sigma);
+		this.waitingTimeDistributionGenerator = new NormalDistributionGenerator(2, waitTimeStd);
 	}
 
 	public EuclideanDistanceBasedDrtEstimator(Network network, double networkDistanceFactor, TripEstimator tripEstimator,

contribs/drt/src/main/java/org/matsim/contrib/drt/estimator/impl/NetworkBasedDrtEstimator.java

@@ -4,6 +4,7 @@
 import org.matsim.api.core.v01.network.Link;
 import org.matsim.contrib.drt.estimator.DrtEstimator;
 import org.matsim.contrib.drt.estimator.impl.distribution.DistributionGenerator;
+import org.matsim.contrib.drt.estimator.impl.distribution.LogNormalDistributionGenerator;
 import org.matsim.contrib.drt.estimator.impl.distribution.NormalDistributionGenerator;
 import org.matsim.contrib.drt.estimator.impl.trip_estimation.ConstantTripEstimator;
 import org.matsim.contrib.drt.estimator.impl.trip_estimation.TripEstimator;
@@ -13,6 +14,8 @@
 import org.matsim.core.utils.collections.Tuple;
 import org.matsim.core.utils.misc.OptionalTime;
 
+import java.util.Random;
+
 /**
  * DRT estimator that uses available data (e.g., real-world operational data, simulation-based data) to provide estimated data for DRT trips.
  */
@@ -71,13 +74,35 @@ public NetworkBasedDrtEstimator(TripEstimator rideDurationEstimator, WaitingTime
 	 * @param waitTimeStd standard deviation of waiting time (normalized to 1)
 	 * @return NetworkBasedDrtEstimator
 	 */
-	public static NetworkBasedDrtEstimator normalDistributed(double estRideTimeAlpha, double estRideTimeBeta, double rideTimeStd, double estMeanWaitTime,
-															 double waitTimeStd) {
+	public static NetworkBasedDrtEstimator normalDistributedNetworkBasedDrtEstimator(double estRideTimeAlpha, double estRideTimeBeta,
+																					 double rideTimeStd, double estMeanWaitTime,
+																					 double waitTimeStd) {
+		return new Builder()
+			.setWaitingTimeEstimator(new ConstantWaitingTimeEstimator(estMeanWaitTime))
+			.setRideDurationEstimator(new ConstantTripEstimator(estRideTimeAlpha, estRideTimeBeta))
+			.setWaitingTimeDistributionGenerator(new NormalDistributionGenerator(1, waitTimeStd))
+			.setRideDurationDistributionGenerator(new NormalDistributionGenerator(2, rideTimeStd))
+			.build();
+	}
+
+	/**
+	 * Example DRT estimator based on the log-normal distributed ride time and normal distributed waiting time
+	 * @param estRideTimeAlpha typical ride duration = alpha * direct ride time + beta, alpha is specified here
+	 * @param estRideTimeBeta typical ride duration = alpha * direct ride time + beta, beta is specified here
+	 * @param mu log-normal distribution parameter for ride duration (normalized to typical ride duration)
+	 * @param sigma log-normal distribution parameter for ride duration (normalized to typical ride duration)
+	 * @param estMeanWaitTime estimated waiting time (i.e., mean wait time)
+	 * @param waitTimeStd standard deviation of waiting time (normalized to 1)
+	 * @return NetworkBasedDrtEstimator
+	 */
+	public static NetworkBasedDrtEstimator mixDistributedNetworkBasedDrtEstimator(double estRideTimeAlpha, double estRideTimeBeta,
+																				  double mu, double sigma, double estMeanWaitTime,
+																				  double waitTimeStd) {
 		return new Builder()
 			.setWaitingTimeEstimator(new ConstantWaitingTimeEstimator(estMeanWaitTime))
 			.setRideDurationEstimator(new ConstantTripEstimator(estRideTimeAlpha, estRideTimeBeta))
-			.setWaitingTimeDistributionGenerator(new NormalDistributionGenerator(4711, waitTimeStd))
-			.setRideDurationDistributionGenerator(new NormalDistributionGenerator(4711, rideTimeStd))
+			.setWaitingTimeDistributionGenerator(new NormalDistributionGenerator(1, waitTimeStd))
+			.setRideDurationDistributionGenerator(new LogNormalDistributionGenerator(2, mu, sigma))
 			.build();
 	}
 
@@ -91,7 +116,7 @@ public Estimate estimate(DrtRoute route, OptionalTime departureTime) {
 		double alpha = alphaBetaTuple.getFirst();
 		double beta = alphaBetaTuple.getSecond();
 		double typicalRideDuration = directRideTIme * alpha + beta;
-		double typicalRideDistance = directDistance * alpha + beta;
+		double typicalRideDistance = (typicalRideDuration / directRideTIme) * directDistance;
 		double typicalWaitingTime = waitingTimeEstimator.estimateWaitTime(fromLinkId, toLinkId, departureTime);
 
 		double estimatedWaitingTime = typicalWaitingTime * waitingTimeDistributionGenerator.generateRandomValue();

contribs/drt/src/main/java/org/matsim/contrib/drt/estimator/impl/distribution/DistributionGenerator.java

@@ -2,7 +2,7 @@
 
 public interface DistributionGenerator {
 	/**
-	 * @return relative value to the typical ride duration
+	 * @return relative value to the typical ride duration (i.e., generate a distribution around 1.0)
 	 */
 	double generateRandomValue();
 

contribs/drt/src/main/java/org/matsim/contrib/drt/estimator/impl/distribution/LogNormalDistributionGenerator.java

@@ -10,16 +10,16 @@ public class LogNormalDistributionGenerator implements DistributionGenerator {
 
 	private final double maxValue;
 
-	public LogNormalDistributionGenerator(Random random, double mu, double sigma) {
-		this.random = new Random();
+	public LogNormalDistributionGenerator(long seed, double mu, double sigma) {
+		this.random = new Random(seed);
 		this.mu = mu;
 		this.sigma = sigma;
 		this.minValue = 0.5;
 		this.maxValue = 3;
 	}
 
-	public LogNormalDistributionGenerator(Random random, double mu, double sigma, double minValue, double maxValue) {
-		this.random = random;
+	public LogNormalDistributionGenerator(long seed, double mu, double sigma, double minValue, double maxValue) {
+		this.random = new Random(seed);
 		this.mu = mu;
 		this.sigma = sigma;
 		this.minValue = minValue;

contribs/drt/src/main/java/org/matsim/contrib/drt/estimator/impl/distribution/NormalDistributionGenerator.java

@@ -26,7 +26,7 @@ public NormalDistributionGenerator(long seed, double std, double minValue, doubl
 
 	@Override
 	public double generateRandomValue() {
-		double randomValue = random.nextGaussian() * std;
+		double randomValue = 1 + random.nextGaussian() * std;
 		randomValue = Math.min(maxValue, randomValue);
 		randomValue = Math.max(minValue, randomValue);
 		return randomValue;