introduce conflict-based replanning

matsim/src/main/java/org/matsim/core/controler/corelisteners/PlansReplanningImpl.java

@@ -24,7 +24,9 @@
 import org.matsim.core.controler.events.ReplanningEvent;
 import org.matsim.core.controler.listener.ReplanningListener;
 import org.matsim.core.replanning.ReplanningContext;
+import org.matsim.core.replanning.ReplanningUtils;
 import org.matsim.core.replanning.StrategyManager;
+import org.matsim.core.replanning.conflicts.ConflictManager;
 
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
@@ -41,21 +43,24 @@
  */
 @Singleton
 final class PlansReplanningImpl implements PlansReplanning, ReplanningListener {
-
 	private final Provider<ReplanningContext> replanningContextProvider;
 	private final Population population;
 	private final StrategyManager strategyManager;
+	private final ConflictManager conflictManager;
 
 	@Inject
-	PlansReplanningImpl(StrategyManager strategyManager, Population pop, Provider<ReplanningContext> replanningContextProvider) {
+	PlansReplanningImpl(StrategyManager strategyManager, ConflictManager conflictManager, Population pop,
+			Provider<ReplanningContext> replanningContextProvider) {
 		this.population = pop;
 		this.strategyManager = strategyManager;
+		this.conflictManager = conflictManager;
 		this.replanningContextProvider = replanningContextProvider;
 	}
 
 	@Override
 	public void notifyReplanning(final ReplanningEvent event) {
+		population.getPersons().values().forEach(ReplanningUtils::setInitialPlan);
 		strategyManager.run(population, event.getIteration(), replanningContextProvider.get());
+		conflictManager.run(population, event.getIteration());
 	}
-
 }

matsim/src/main/java/org/matsim/core/replanning/ReplanningUtils.java

@@ -22,13 +22,40 @@
 
 package org.matsim.core.replanning;
 
+import javax.annotation.Nullable;
+
 import org.matsim.api.core.v01.population.BasicPlan;
+import org.matsim.api.core.v01.population.Person;
+import org.matsim.api.core.v01.population.Plan;
 
 public final class ReplanningUtils {
 
+	static public final String INITIAl_PLAN_ATTRIBUTE = "isInitialPlan";
+
+	public static boolean isInitialPlan(Plan plan) {
+		Boolean isInitialPlan = (Boolean) plan.getAttributes().getAttribute(INITIAl_PLAN_ATTRIBUTE);
+		return isInitialPlan != null && isInitialPlan;
+	}
+
+	@Nullable
+	public static Plan getInitialPlan(Person person) {
+		for (Plan plan : person.getPlans()) {
+			if (isInitialPlan(plan)) {
+				return plan;
+			}
+		}
+
+		return null;
+	}
+
+	public static void setInitialPlan(Person person) {
+		person.getPlans().forEach(plan -> plan.getAttributes().removeAttribute(INITIAl_PLAN_ATTRIBUTE));
+		person.getSelectedPlan().getAttributes().putAttribute(INITIAl_PLAN_ATTRIBUTE, true);
+	}
+
 	/**
 	 * Return whether a strategy is innovative, i.e. is producing new plans.
-	 * */
+	 */
 	public static <P extends BasicPlan, R> boolean isInnovativeStrategy(GenericPlanStrategy<P, R> planStrategy) {
 		return !isOnlySelector(planStrategy);
 	}

matsim/src/main/java/org/matsim/core/replanning/StrategyManagerModule.java

@@ -35,6 +35,7 @@
 import org.matsim.core.controler.OutputDirectoryHierarchy;
 import org.matsim.core.replanning.choosers.StrategyChooser;
 import org.matsim.core.replanning.choosers.WeightedStrategyChooser;
+import org.matsim.core.replanning.conflicts.ConflictModule;
 import org.matsim.core.replanning.modules.ExternalModule;
 import org.matsim.core.replanning.selectors.RandomPlanSelector;
 import org.matsim.core.replanning.strategies.DefaultPlanStrategiesModule;
@@ -92,6 +93,8 @@ public void install() {
 				// (settings is the key ... ok.  The Key.get(...) returns the PlanStrategy that was registered under its name at (*) above.)
 			}
 		}
+
+		install(new ConflictModule());
 	}
 
 	/**

matsim/src/main/java/org/matsim/core/replanning/conflicts/ConflictManager.java

@@ -0,0 +1,111 @@
+package org.matsim.core.replanning.conflicts;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.matsim.api.core.v01.Id;
+import org.matsim.api.core.v01.IdSet;
+import org.matsim.api.core.v01.population.Person;
+import org.matsim.api.core.v01.population.Plan;
+import org.matsim.api.core.v01.population.Population;
+import org.matsim.core.replanning.ReplanningUtils;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * This class handles conflicts during replanning. ConflictResolvers are used to
+ * identify agents whose plans are conflicting with others and need to be
+ * "rejected" in order to resolve these conflicts. "Rejecting" means to switch
+ * those agents back to a plan in their memory that does not cause any
+ * conflicts. Those are plans that are not "potentially conflicting", i.e.,
+ * could interfere in any way with another agent. Those are usually plans that
+ * don't contain a certain restricted/limited/capacitated mode or resource. The
+ * logic of conflicts is defined using the ConflictResolver interface.
+ */
+public class ConflictManager {
+	private final static Logger logger = LogManager.getLogger(ConflictManager.class);
+
+	private final Set<ConflictResolver> resolvers;
+	private final ConflictWriter writer;
+	private final Random random;
+
+	public ConflictManager(Set<ConflictResolver> resolvers, ConflictWriter writer, Random random) {
+		this.resolvers = resolvers;
+		this.random = random;
+		this.writer = writer;
+	}
+
+	public void run(Population population, int iteration) {
+		if (resolvers.size() == 0) {
+			return;
+		}
+
+		logger.info("Resolving conflicts ...");
+
+		Map<String, Integer> conflictCounts = new HashMap<>();
+		IdSet<Person> conflictingIds = new IdSet<>(Person.class);
+
+		for (ConflictResolver resolver : resolvers) {
+			IdSet<Person> resolverConflictingIds = resolver.resolve(population, iteration);
+			conflictCounts.put(resolver.getName(), resolverConflictingIds.size());
+			conflictingIds.addAll(resolverConflictingIds);
+		}
+
+		logger.info("  Conflicts: " + conflictCounts.entrySet().stream()
+				.map(entry -> String.format("%s=%d", entry.getKey(), entry.getValue()))
+				.collect(Collectors.joining(", ")));
+
+		int switchedToInitialCount = 0;
+		int switchedToRandomCount = 0;
+
+		for (Id<Person> personId : conflictingIds) {
+			Person person = population.getPersons().get(personId);
+
+			// If the initial plan is non-conflicting, switch back to it
+			Plan initialPlan = ReplanningUtils.getInitialPlan(person);
+
+			if (initialPlan != null && !isPotentiallyConflicting(initialPlan)) {
+				person.setSelectedPlan(initialPlan);
+				switchedToInitialCount++;
+			} else {
+				// Select a random non-conflicting plan
+				List<Plan> candidates = person.getPlans().stream().filter(p -> !isPotentiallyConflicting(p))
+						.collect(Collectors.toList());
+				Preconditions.checkState(candidates.size() > 0,
+						String.format("Agent %s has no non-conflicting plan", personId));
+
+				// Shuffle, and select the first
+				Collections.shuffle(candidates, random);
+				person.setSelectedPlan(candidates.get(0));
+
+				switchedToRandomCount++;
+			}
+		}
+
+		logger.info(String.format("  %d (%.2f%%) switched to initial", switchedToInitialCount,
+				(double) switchedToInitialCount / population.getPersons().size()));
+		logger.info(String.format("  %d (%.2f%%) switched to random", switchedToRandomCount,
+				(double) switchedToRandomCount / population.getPersons().size()));
+
+		writer.write(iteration, switchedToInitialCount, switchedToRandomCount, conflictCounts);
+
+		logger.info("  Done resolving conflicts!");
+	}
+
+	public boolean isPotentiallyConflicting(Plan plan) {
+		for (ConflictResolver resolver : resolvers) {
+			if (resolver.isPotentiallyConflicting(plan)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+}

matsim/src/main/java/org/matsim/core/replanning/conflicts/ConflictModule.java

@@ -0,0 +1,70 @@
+package org.matsim.core.replanning.conflicts;
+
+import java.io.File;
+import java.util.Random;
+import java.util.Set;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.matsim.core.controler.AbstractModule;
+import org.matsim.core.controler.OutputDirectoryHierarchy;
+import org.matsim.core.gbl.MatsimRandom;
+
+import com.google.inject.Binder;
+import com.google.inject.Provides;
+import com.google.inject.Singleton;
+import com.google.inject.binder.LinkedBindingBuilder;
+import com.google.inject.multibindings.Multibinder;
+
+/**
+ * Prepares injection of the conflict resolution logic during replanning
+ * 
+ * @author Sebastian Hörl (sebhoerl), IRT SystemX
+ */
+public class ConflictModule extends AbstractModule {
+	private final static Logger logger = LogManager.getLogger(ConflictModule.class);
+
+	private final static String OUTPUT_FILE = "conflicts.csv";
+
+	@Override
+	public void install() {
+	}
+
+	@Provides
+	@Singleton
+	ConflictWriter provideConflictWriter(OutputDirectoryHierarchy outputDirectoryHierarchy) {
+		File outputPath = new File(outputDirectoryHierarchy.getOutputFilename(OUTPUT_FILE));
+		return new ConflictWriter(outputPath);
+	}
+
+	@Provides
+	@Singleton
+	ConflictManager provideConflictManager(Set<ConflictResolver> resolvers, ConflictWriter writer) {
+		if (!getConfig().replanning().getPlanSelectorForRemoval()
+				.equals(WorstPlanForRemovalSelectorWithConflicts.SELECTOR_NAME)) {
+			logger.warn("The replanning.planSelectorForRemoval is not set to "
+					+ WorstPlanForRemovalSelectorWithConflicts.SELECTOR_NAME
+					+ ". This will likely cause problems with the conflict logic if you are not sure what you are doing.");
+		}
+
+		Random random = MatsimRandom.getLocalInstance();
+		return new ConflictManager(resolvers, writer, random);
+	}
+
+	static Multibinder<ConflictResolver> getMultibinder(Binder binder) {
+		return Multibinder.newSetBinder(binder, ConflictResolver.class);
+	}
+
+	/**
+	 * Allows to bind a conflict resolver in an AbstractModule, for instance:
+	 * 
+	 * <code>
+	 * ConflictModule.bindResolver(binder()).toInstance(new ConflictResolver() {
+	 *    // ...
+	 * });
+	 * </code>
+	 */
+	static public LinkedBindingBuilder<ConflictResolver> bindResolver(Binder binder) {
+		return getMultibinder(binder).addBinding();
+	}
+}

matsim/src/main/java/org/matsim/core/replanning/conflicts/ConflictResolver.java

@@ -0,0 +1,23 @@
+package org.matsim.core.replanning.conflicts;
+
+import org.matsim.api.core.v01.IdSet;
+import org.matsim.api.core.v01.population.Person;
+import org.matsim.api.core.v01.population.Plan;
+import org.matsim.api.core.v01.population.Population;
+
+/**
+ * This interface is called after standard replanning. Its purpose is to check
+ * the population and detect any conflicts between agents. The interface must
+ * then return a list of agents that should be reset to a non-conflicting plan
+ * in order to resolve all conflicts. Plans that are not conflicting are
+ * identified as such using the isPotentiallyConflicting method.
+ * 
+ * @author Sebastian Hörl (sebhoerl), IRT SystemX
+ */
+public interface ConflictResolver {
+	IdSet<Person> resolve(Population population, int iteration);
+
+	boolean isPotentiallyConflicting(Plan plan);
+
+	String getName();
+}

matsim/src/main/java/org/matsim/core/replanning/conflicts/ConflictWriter.java

@@ -0,0 +1,61 @@
+package org.matsim.core.replanning.conflicts;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import org.matsim.core.utils.io.IOUtils;
+
+/**
+ * Writes high-level statistics on the conflict resolution process per iteration
+ * 
+ * @author Sebastian Hörl (sebhoerl), IRT SystemX
+ */
+public class ConflictWriter {
+	private final File outputPath;
+
+	public ConflictWriter(File outputPath) {
+		this.outputPath = outputPath;
+	}
+
+	public void write(int iteration, int rejectedToInitial, int rejectedToRandom, Map<String, Integer> conflictCounts) {
+		boolean writeHeader = !outputPath.exists();
+
+		List<String> resolvers = new ArrayList<>(conflictCounts.keySet());
+		Collections.sort(resolvers);
+
+		try {
+			BufferedWriter writer = IOUtils.getAppendingBufferedWriter(outputPath.getPath());
+
+			if (writeHeader) {
+				List<String> header = new ArrayList<>(
+						Arrays.asList("iteration", "rejected_total", "switched_to_initial", "switched_to_random"));
+				resolvers.stream().map(r -> "resolver:" + r).forEach(header::add);
+
+				writer.write(String.join(";", header) + "\n");
+			}
+
+			List<String> row = new ArrayList<>(Arrays.asList(String.valueOf(iteration), //
+					String.valueOf(rejectedToInitial + rejectedToRandom), //
+					String.valueOf(rejectedToInitial), //
+					String.valueOf(rejectedToRandom) //
+			));
+
+			for (String resolver : resolvers) {
+				row.add(String.valueOf(conflictCounts.get(resolver)));
+			}
+
+			writer.write(String.join(";", row) + "\n");
+
+			writer.close();
+		} catch (IOException e) {
+			throw new UncheckedIOException(e);
+		}
+	}
+}