fix: preventing the summing of two error terms in FeederDrtUtilityEstimator (#246)

Author: tkchouaki

core/src/main/java/org/eqasim/core/simulation/mode_choice/epsilon/EpsilonAdapter.java

@@ -24,4 +24,8 @@ public double estimateUtility(Person person, DiscreteModeChoiceTrip trip, List<?
 		utility += epsilonProvider.getEpsilon(person.getId(), trip.getIndex(), mode);
 		return utility;
 	}
+
+	public UtilityEstimator getDelegate() {
+		return this.delegate;
+	}
 }

core/src/main/java/org/eqasim/core/simulation/modes/feeder_drt/mode_choice/EqasimFeederDrtModeChoiceModule.java

@@ -4,11 +4,13 @@
 import com.google.inject.Provides;
 import org.eqasim.core.components.config.EqasimConfigGroup;
 import org.eqasim.core.simulation.mode_choice.AbstractEqasimExtension;
+import org.eqasim.core.simulation.mode_choice.epsilon.EpsilonAdapter;
 import org.eqasim.core.simulation.mode_choice.utilities.UtilityEstimator;
 import org.eqasim.core.simulation.modes.feeder_drt.mode_choice.constraints.FeederDrtConstraint;
 import org.eqasim.core.simulation.modes.feeder_drt.config.MultiModeFeederDrtConfigGroup;
 import org.eqasim.core.simulation.modes.feeder_drt.mode_choice.utilities.estimator.DefaultFeederDrtUtilityEstimator;
 
+import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 
@@ -26,6 +28,14 @@ protected void installEqasimExtension() {
     public DefaultFeederDrtUtilityEstimator provideDefaultFeederDrtUtilityEstimator(EqasimConfigGroup eqasimConfigGroup, MultiModeFeederDrtConfigGroup multiModeFeederDrtConfigGroup, Map<String, Provider<UtilityEstimator>> utilityEstimatorProviders) {
         Map<String, UtilityEstimator> ptEstimators = multiModeFeederDrtConfigGroup.getModalElements().stream().collect(Collectors.toMap(cfg -> cfg.mode, cfg -> utilityEstimatorProviders.get(eqasimConfigGroup.getEstimators().get(cfg.ptModeName)).get()));
         Map<String, UtilityEstimator> drtEstimators = multiModeFeederDrtConfigGroup.getModalElements().stream().collect(Collectors.toMap(cfg -> cfg.mode, cfg -> utilityEstimatorProviders.get(eqasimConfigGroup.getEstimators().get(cfg.accessEgressModeName)).get()));
+        // When we use the Epsilon adapter, we do not want to sum the pseudo-random errors of each sub-mode but rather only use one pseudo-error specific to the current mode
+        for(Map<String, UtilityEstimator> map: List.of(ptEstimators, drtEstimators)) {
+            for(String mode: map.keySet()) {
+                if(map.get(mode) instanceof EpsilonAdapter epsilonAdapter) {
+                    map.put(mode, epsilonAdapter.getDelegate());
+                }
+            }
+        }
         return new DefaultFeederDrtUtilityEstimator(ptEstimators, drtEstimators);
     }