package org.opentrafficsim.road.gtu.generator;
   
   import java.util.ArrayList;
   import java.util.Collections;
   import java.util.Comparator;
   import java.util.LinkedHashMap;
   import java.util.LinkedHashSet;
   import java.util.List;
   import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  
  import org.djunits.unit.SpeedUnit;
  import org.djunits.value.vdouble.scalar.Length;
  import org.djunits.value.vdouble.scalar.Speed;
  import org.djutils.exceptions.Throw;
  import org.opentrafficsim.core.gtu.GtuException;
  import org.opentrafficsim.core.gtu.GtuType;
  import org.opentrafficsim.core.math.Draw;
  import org.opentrafficsim.core.network.Link;
  import org.opentrafficsim.core.network.NetworkException;
  import org.opentrafficsim.core.network.Node;
  import org.opentrafficsim.core.network.route.Route;
  import org.opentrafficsim.road.gtu.generator.GeneratorPositions.RoadPosition.BySpeed;
  import org.opentrafficsim.road.gtu.generator.GeneratorPositions.RoadPosition.ByValue;
  import org.opentrafficsim.road.gtu.generator.characteristics.LaneBasedGtuCharacteristics;
  import org.opentrafficsim.road.network.lane.CrossSectionLink;
  import org.opentrafficsim.road.network.lane.Lane;
  import org.opentrafficsim.road.network.lane.LanePosition;
  
  import nl.tudelft.simulation.jstats.streams.StreamInterface;
  
  /**
   * Helper class for vehicle generation which can draw the next GTU position to try to place a GTU. If the GTU can not be placed,
   * it should be included in a queue. This class requires the number of unplaced GTU's per lane, in order to appropriately divide
   * traffic over the lanes.
   * <p>
   * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
   * </p>
   * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
   * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
   * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
   */
  public interface GeneratorPositions
  {
  
      /**
       * Draw a new position to generate a GTU.
       * @param gtuType GtuType; GTU type.
       * @param characteristics LaneBasedGtuCharacteristics; characteristics of the generated GTU.
       * @param unplaced Map&lt;CrossSectionLink, Map&lt;Integer, Integer&gt;&gt;; number of unplaced GTUs per lane, counting from
       *            the right and starting at 1.
       * @return GeneratorLanePosition; new position to generate a GTU.
       * @throws GtuException when the underlying structure is inconsistent for drawing
       */
      GeneratorLanePosition draw(GtuType gtuType, LaneBasedGtuCharacteristics characteristics,
              Map<CrossSectionLink, Map<Integer, Integer>> unplaced) throws GtuException;
  
      /**
       * Returns all underlying positions.
       * @return all underlying positions.
       */
      Set<GeneratorLanePosition> getAllPositions();
  
      /**
       * Create a GeneratorPositions object to draw positions from. The given positions are grouped per link. Lanes are drawn
       * without bias. Each link receives a weight equal to the number of lanes.
       * @param positions Set&lt;LanePosition&gt;; all considered positions, each lane is considered separately
       * @param stream StreamInterface; stream for random numbers
       * @return GeneratorPositions; object to draw positions from
       */
      static GeneratorPositions create(final Set<LanePosition> positions, final StreamInterface stream)
      {
          return create(positions, stream, null, null, null);
      }
  
      /**
       * Create a GeneratorPositions object to draw positions from. The given positions are grouped per link. Each link receives a
       * weight equal to the number of lanes.
       * @param positions Set&lt;LanePosition&gt;; all considered positions, each lane is considered separately
       * @param stream StreamInterface; stream for random numbers
       * @param biases LaneBiases; lane biases for GTU types
       * @return GeneratorPositions; object to draw positions from
       */
      static GeneratorPositions create(final Set<LanePosition> positions, final StreamInterface stream, final LaneBiases biases)
      {
          return create(positions, stream, biases, null, null);
      }
  
      /**
       * Create a GeneratorPositions object to draw positions from. The given positions are grouped per link. Lanes are drawn
       * without bias.
       * @param positions Set&lt;LanePosition&gt;; all considered positions, each lane is considered separately
       * @param stream StreamInterface; stream for random numbers
       * @param linkWeights Map&lt;CrossSectionLink, Double&gt;; weight per link direction
       * @param viaNodes Map&lt;CrossSectionLink, Node&gt;; nodes connectors feed to for each link where GTU's will be generated
       * @return GeneratorPositions; object to draw positions from
       */
     static GeneratorPositions create(final Set<LanePosition> positions, final StreamInterface stream,
             final Map<CrossSectionLink, Double> linkWeights, final Map<CrossSectionLink, Node> viaNodes)
     {
         return create(positions, stream, null, linkWeights, viaNodes);
     }
 
     /**
      * Create a GeneratorPositions object to draw positions from. The given positions are grouped per link.
      * @param positions Set&lt;LanePosition&gt;; all considered positions, each lane is considered separately
      * @param stream StreamInterface; stream for random numbers
      * @param laneBiases LaneBiases; lane biases for GTU types
      * @param linkWeights Map&lt;CrossSectionLink, Double&gt;; weight per link
      * @param viaNodes Map&lt;CrossSectionLink, Node&gt;; nodes connectors feed to for each link where GTU's will be generated
      * @return GeneratorPositions; object to draw positions from
      */
     static GeneratorPositions create(final Set<LanePosition> positions, final StreamInterface stream,
             final LaneBiases laneBiases, final Map<CrossSectionLink, Double> linkWeights,
             final Map<CrossSectionLink, Node> viaNodes)
     {
 
         // group directions per link
         Map<Link, Set<LanePosition>> linkSplit = new LinkedHashMap<>();
         for (LanePosition position : positions)
         {
             linkSplit.computeIfAbsent(position.lane().getLink(), (link) -> new LinkedHashSet<>()).add(position);
         }
 
         // create list of GeneratorLinkPositions
         List<GeneratorLinkPosition> linkPositions = new ArrayList<>();
         Set<GeneratorLanePosition> allLanePositions = new LinkedHashSet<>();
         for (Link splitLink : linkSplit.keySet())
         {
             List<Lane> lanes = ((CrossSectionLink) splitLink).getLanes();
             // let's sort the lanes by lateral position
             Collections.sort(lanes, new Comparator<Lane>()
             {
                 /** {@inheritDoc} */
                 @Override
                 public int compare(final Lane lane1, final Lane lane2)
                 {
                     Length lat1 = lane1.getOffsetAtBegin();
                     Length lat2 = lane2.getOffsetAtBegin();
                     return lat1.compareTo(lat2);
                 }
             });
             // create list of GeneratorLanePositions
             List<GeneratorLanePosition> lanePositions = new ArrayList<>();
             for (LanePosition lanePosition : linkSplit.get(splitLink))
             {
                 lanePositions.add(new GeneratorLanePosition(lanes.indexOf(lanePosition.lane()) + 1, lanePosition,
                         (CrossSectionLink) splitLink));
             }
             allLanePositions.addAll(lanePositions);
             // create the GeneratorLinkPosition
             if (linkWeights == null)
             {
                 linkPositions.add(new GeneratorLinkPosition(lanePositions, splitLink, stream, laneBiases));
             }
             else
             {
                 Double weight = linkWeights.get(splitLink);
                 Throw.whenNull(weight, "Using link weights for GTU generation, but no weight for link %s is defined.",
                         splitLink);
                 linkPositions.add(new GeneratorLinkPosition(lanePositions, splitLink, stream, laneBiases, weight,
                         viaNodes.get(splitLink)));
             }
         }
 
         // create the GeneratorZonePosition
         GeneratorZonePosition position = new GeneratorZonePosition(linkPositions);
         return new GeneratorPositions()
         {
             /** {@inheritDoc} */
             @Override
             public GeneratorLanePosition draw(final GtuType gtuType, final LaneBasedGtuCharacteristics characteristics,
                     final Map<CrossSectionLink, Map<Integer, Integer>> unplaced) throws GtuException
             {
                 GeneratorLinkPosition linkPosition =
                         position.draw(gtuType, stream, characteristics.getDestination(), characteristics.getRoute());
                 Speed desiredSpeed = characteristics.getStrategicalPlannerFactory().peekDesiredSpeed(gtuType,
                         linkPosition.speedLimit(gtuType), characteristics.getMaximumSpeed());
                 return linkPosition.draw(gtuType, unplaced.get(linkPosition.getLink()), desiredSpeed);
             }
 
             /** {@inheritDoc} */
             @Override
             public Set<GeneratorLanePosition> getAllPositions()
             {
                 return allLanePositions;
             }
         };
     }
 
     /**
      * Class representing a vehicle generation lane, providing elementary information for randomly drawing links and lanes.
      * <p>
      * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
      * <br>
      * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
      * </p>
      * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
      * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
      */
     final class GeneratorLanePosition
     {
 
         /** Lane number, where 1 is the right-most lane. */
         private final int laneNumber;
 
         /** Position. */
         private final LanePosition position;
 
         /** Link. */
         private final CrossSectionLink link;
 
         /**
          * Constructor.
          * @param laneNumber int; lane number, where 1 is the right-most lane
          * @param position LanePosition; position set, representing a single GTU position on the network
          * @param link CrossSectionLink; link
          */
         GeneratorLanePosition(final int laneNumber, final LanePosition position, final CrossSectionLink link)
         {
             this.laneNumber = laneNumber;
             this.position = position;
             this.link = link;
         }
 
         /**
          * Returns the lane number, where 1 is the right-most lane.
          * @return lane number, where 1 is the right-most lane
          */
         int getLaneNumber()
         {
             return this.laneNumber;
         }
 
         /**
          * Returns whether this lane is accessible to the GTU type.
          * @param gtuType GtuType; gtu type
          * @return boolean; whether this lane is accessible to the GTU type
          */
         boolean allows(final GtuType gtuType)
         {
             return this.position.lane().getType().isCompatible(gtuType);
         }
 
         /**
          * Returns the contained position set, representing a single GTU position on the network.
          * @return LanePosition; contained position set, representing a single GTU position on the network
          */
         LanePosition getPosition()
         {
             return this.position;
         }
 
         /**
          * Returns the link.
          * @return CrossSectionLink; link
          */
         CrossSectionLink getLink()
         {
             return this.link;
         }
 
         /** {@inheritDoc} */
         @Override
         public int hashCode()
         {
             return Objects.hash(this.laneNumber, this.link, this.position);
         }
 
         /** {@inheritDoc} */
         @Override
         public boolean equals(final Object obj)
         {
             if (this == obj)
             {
                 return true;
             }
             if (obj == null)
             {
                 return false;
             }
             if (getClass() != obj.getClass())
             {
                 return false;
             }
             GeneratorLanePosition other = (GeneratorLanePosition) obj;
             return this.laneNumber == other.laneNumber && Objects.equals(this.link, other.link)
                     && Objects.equals(this.position, other.position);
         }
 
         /** {@inheritDoc} */
         @Override
         public String toString()
         {
             return "GeneratorLanePosition [laneNumber=" + this.laneNumber + ", position=" + this.position + ", link="
                     + this.link + "]";
         }
 
     }
 
     /**
      * Class representing a vehicle generation link to provide individual generation positions.
      * <p>
      * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
      * <br>
      * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
      * </p>
      * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
      * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
      */
     final class GeneratorLinkPosition
     {
 
         /** Contained lanes. */
         private final List<GeneratorLanePosition> positions;
 
         /** The link. */
         private final Link link;
 
         /** Random stream. */
         private final StreamInterface stream;
 
         /** Lane bias. */
         private final LaneBiases laneBiases;
 
         /** Weight for drawing this link. */
         private final double weight;
 
         /** Node by which a connector connects, may be {@code null}. */
         private final Node viaNode;
 
         /**
          * Constructor.
          * @param positions List&lt;GeneratorLanePosition&gt;; contained lanes
          * @param link Link; the link
          * @param stream StreamInterface; stream
          * @param laneBiases LaneBiases; lane biases
          */
         GeneratorLinkPosition(final List<GeneratorLanePosition> positions, final Link link, final StreamInterface stream,
                 final LaneBiases laneBiases)
         {
             this.positions = positions;
             this.link = link;
             this.stream = stream;
             this.laneBiases = laneBiases;
             this.weight = -1;
             this.viaNode = null;
         }
 
         /**
          * Constructor.
          * @param positions List&lt;GeneratorLanePosition&gt;; contained lanes
          * @param link Link; the link
          * @param stream StreamInterface; stream
          * @param laneBiases LaneBiases; lane biases
          * @param weight double; weight for drawing this link
          * @param viaNode Node; node by which a connector connects
          */
         GeneratorLinkPosition(final List<GeneratorLanePosition> positions, final Link link, final StreamInterface stream,
                 final LaneBiases laneBiases, final double weight, final Node viaNode)
         {
             this.positions = positions;
             this.link = link;
             this.stream = stream;
             this.laneBiases = laneBiases;
             this.weight = weight;
             this.viaNode = viaNode;
         }
 
         /**
          * Return the link.
          * @return CrossSectionLink; link
          */
         Link getLink()
         {
             return this.link;
         }
 
         /**
          * Returns the weight for this link. This is either a predefined weight, or the number of lanes for the GTU type.
          * @param gtuType GtuType; GTU type
          * @return double; weight for this link
          */
         double getWeight(final GtuType gtuType)
         {
             if (this.weight < 0.0)
             {
                 return getNumberOfLanes(gtuType);
             }
             return this.weight;
         }
 
         /**
          * Returns the node by which a connector connects.
          * @return the node by which a connector connects
          */
         Node getViaNode()
         {
             return this.viaNode;
         }
 
         /**
          * Returns the number of accessible lanes for the GTU type.
          * @param gtuType GtuType; GTU type
          * @return int; number of accessible lanes for the GTU type
          */
         int getNumberOfLanes(final GtuType gtuType)
         {
             int numberOfLanes = 0;
             for (GeneratorLanePosition lanePosition : this.positions)
             {
                 if (lanePosition.allows(gtuType))
                 {
                     numberOfLanes++;
                 }
             }
             return numberOfLanes;
         }
 
         /**
          * Draws a specific GeneratorLanePosition utilizing lane biases of GTU types.
          * @param gtuType GtuType; GTU type
          * @param unplaced Map&lt;Integer, Integer&gt;; number of unplaced GTUs per lane. The lane number should match with
          *            {@code GeneratorLanePosition.getLaneNumber()}, where 1 is the right-most lane. Missing lanes are assumed
          *            to have no queue.
          * @param desiredSpeed Speed; desired speed, possibly used to determine the biased road position
          * @return GeneratorLanePosition; specific GeneratorLanePosition utilizing lane biases of GTU types
          */
         GeneratorLanePosition draw(final GtuType gtuType, final Map<Integer, Integer> unplaced, final Speed desiredSpeed)
         {
             Map<GeneratorLanePosition, Double> map = new LinkedHashMap<>();
             for (int i = 0; i < this.positions.size(); i++)
             {
                 GeneratorLanePosition lanePosition = this.positions.get(i);
                 if (lanePosition.allows(gtuType))
                 {
                     GtuType type = gtuType;
                     boolean found = false;
                     while (this.laneBiases != null && !found && type != null)
                     {
                         if (this.laneBiases.contains(type))
                         {
                             found = true;
                             int laneNum = lanePosition.getLaneNumber();
                             int unplacedTemplates = unplaced == null ? 0 : unplaced.getOrDefault(laneNum, 0);
                             double w = this.laneBiases.getBias(type).calculateWeight(laneNum, getNumberOfLanes(gtuType),
                                     unplacedTemplates, desiredSpeed);
                             map.put(lanePosition, w);
                         }
                         type = type.getParent();
                     }
                     if (!found)
                     {
                         map.put(lanePosition, 1.0);
                     }
                 }
             }
             if (0 == map.size())
             {
                 System.err.println("This really, really can't work...");
             }
             return Draw.drawWeighted(map, this.stream);
         }
 
         /** {@inheritDoc} */
         @Override
         public String toString()
         {
             return "GeneratorLinkPosition [positions=" + this.positions + "]";
         }
 
         /**
          * @param gtuType GtuType; GTU type
          * @return Speed; speed limit
          */
         public Speed speedLimit(final GtuType gtuType)
         {
             Speed speedLimit = null;
             for (GeneratorLanePosition pos : this.positions)
             {
                 try
                 {
                     Speed limit = pos.getPosition().lane().getSpeedLimit(gtuType);
                     if (speedLimit == null || limit.lt(speedLimit))
                     {
                         speedLimit = limit;
                     }
                 }
                 catch (NetworkException exception)
                 {
                     // ignore
                 }
             }
             Throw.when(speedLimit == null, IllegalStateException.class, "No speed limit could be determined for GtuType %s.",
                     gtuType);
             return speedLimit;
         }
 
     }
 
     /**
      * Class representing a vehicle generation zone to provide individual generation positions.
      * <p>
      * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
      * <br>
      * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
      * </p>
      * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
      * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
      */
     final class GeneratorZonePosition
     {
 
         /** Contained links. */
         private final List<GeneratorLinkPosition> positions;
 
         /**
          * Constructor.
          * @param positions List&lt;GeneratorLinkPosition&gt;; contained links
          */
         GeneratorZonePosition(final List<GeneratorLinkPosition> positions)
         {
             this.positions = positions;
         }
 
         /**
          * Draws a GeneratorLinkPosition using number of accessible lanes for the GtuType as weight, and a GeneratorLanePosition
          * from that.
          * @param gtuType GtuType; GTU type
          * @param stream StreamInterface; stream for random numbers
          * @param destination Node; destination node
          * @param route Route; route, may be {@code null}
          * @return GeneratorLanePosition; draws a LinkPosition using number of accessible lanes for the GtuType as weight, and a
          *         GeneratorLanePosition from that
          */
         GeneratorLinkPosition draw(final GtuType gtuType, final StreamInterface stream, final Node destination,
                 final Route route)
         {
             Map<GeneratorLinkPosition, Double> map = new LinkedHashMap<>();
             for (int i = 0; i < this.positions.size(); i++)
             {
                 GeneratorLinkPosition glp = this.positions.get(i);
                 Link link = glp.getLink();
                 if (route != null)
                 {
                     int from = route.indexOf(link.getStartNode());
                     int to = route.indexOf(link.getEndNode());
                     if (from > -1 && to > -1 && to - from == 1)
                     {
                         map.put(glp, glp.getWeight(gtuType));
                     }
                 }
                 else
                 {
                     // let's check whether any route is possible over this link
                     if (glp.getViaNode() != null)
                     {
                         Route r;
                         try
                         {
                             r = glp.getViaNode().getNetwork().getShortestRouteBetween(gtuType, glp.getViaNode(), destination);
                         }
                         catch (NetworkException exception)
                         {
                             r = null;
                         }
                         if (r != null)
                         {
                             map.put(glp, glp.getWeight(gtuType));
                         }
                     }
                     else
                     {
                         map.put(glp, glp.getWeight(gtuType));
                     }
                 }
             }
             return Draw.drawWeighted(map, stream);
         }
 
         /** {@inheritDoc} */
         @Override
         public String toString()
         {
             return "GeneratorZonePosition [positions=" + this.positions + "]";
         }
 
     }
 
     /**
      * Set of lane biases per GTU type.
      * <p>
      * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
      * <br>
      * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
      * </p>
      * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
      * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
      */
     final class LaneBiases
     {
 
         /** Biases per GTU type. */
         private final Map<GtuType, LaneBias> biases = new LinkedHashMap<>();
 
         /**
          * Adds a GTU bias for randomly drawing a lane.
          * @param gtuType GtuType; gtu type
          * @param bias LaneBias; bias
          * @return LaneBiases; lane biases for method chaining
          */
         public LaneBiases addBias(final GtuType gtuType, final LaneBias bias)
         {
             Throw.whenNull(gtuType, "GTU type may not be null.");
             Throw.whenNull(bias, "Bias may not be null.");
             this.biases.put(gtuType, bias);
             return this;
         }
 
         /**
          * Whether a bias is defined for the given type.
          * @param gtuType GtuType; GTU type
          * @return whether a bias is defined for the given type
          */
         public boolean contains(final GtuType gtuType)
         {
             return this.biases.containsKey(gtuType);
         }
 
         /**
          * Returns the bias of given GTU type, or {@code Bias.None} if none defined for the GTU type.
          * @param gtuType GtuType; GTU type
          * @return Bias; bias of the GTU type
          */
         public LaneBias getBias(final GtuType gtuType)
         {
             return this.biases.getOrDefault(gtuType, LaneBias.NONE);
         }
 
         /** {@inheritDoc} */
         @Override
         public String toString()
         {
             return "LaneBiases [" + this.biases + "]";
         }
 
     }
 
     /**
      * Vehicle generation lateral bias. Includes a lane maximum, e.g. trucks only on 2 right-hand lanes.
      * <p>
      * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
      * <br>
      * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
      * </p>
      * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
      * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
      */
     final class LaneBias
     {
 
         /** No bias. */
         public static final LaneBias NONE = new LaneBias(new ByValue(0.0), 0.0, Integer.MAX_VALUE);
 
         /** Weak left-hand bias, 2nd left lane contains 50% relative to left most lane, in free traffic. */
         public static final LaneBias WEAK_LEFT = new LaneBias(new ByValue(1.0), 1.0, Integer.MAX_VALUE);
 
         /** Left-hand bias, 2nd left lane contains 25% relative to left most lane, in free traffic. */
         public static final LaneBias LEFT = new LaneBias(new ByValue(1.0), 2.0, Integer.MAX_VALUE);
 
         /** Strong left-hand bias, 2nd left lane contains 3.125% relative to left most lane, in free traffic. */
         public static final LaneBias STRONG_LEFT = new LaneBias(new ByValue(1.0), 5.0, Integer.MAX_VALUE);
 
         /** Weak middle bias, 2nd left lane contains 50% relative to left most lane, in free traffic. */
         public static final LaneBias WEAK_MIDDLE = new LaneBias(new ByValue(0.5), 1.0, Integer.MAX_VALUE);
 
         /** Middle bias, 2nd left lane contains 25% relative to left most lane, in free traffic. */
         public static final LaneBias MIDDLE = new LaneBias(new ByValue(0.5), 2.0, Integer.MAX_VALUE);
 
         /** Strong middle bias, 2nd left lane contains 3.125% relative to left most lane, in free traffic. */
         public static final LaneBias STRONG_MIDDLE = new LaneBias(new ByValue(0.5), 5.0, Integer.MAX_VALUE);
 
         /** Weak right-hand bias, 2nd right lane contains 50% relative to right most lane, in free traffic. */
         public static final LaneBias WEAK_RIGHT = new LaneBias(new ByValue(0.0), 1.0, Integer.MAX_VALUE);
 
         /** Right-hand bias, 2nd right lane contains 25% relative to right most lane, in free traffic. */
         public static final LaneBias RIGHT = new LaneBias(new ByValue(0.0), 2.0, Integer.MAX_VALUE);
 
         /** Strong right-hand bias, 2nd right lane contains 3.125% relative to right most lane, in free traffic. */
         public static final LaneBias STRONG_RIGHT = new LaneBias(new ByValue(0.0), 5.0, Integer.MAX_VALUE);
 
         /** Strong right-hand bias, limited to a maximum of 2 lanes. */
         public static final LaneBias TRUCK_RIGHT = new LaneBias(new ByValue(0.0), 5.0, 2);
 
         /**
          * Returns a bias by speed with normal extent.
          * @param leftSpeed Speed; desired speed for full left bias
          * @param rightSpeed Speed; desired speed for full right bias
          * @return bias by speed with normal extent
          */
         public static LaneBias bySpeed(final Speed leftSpeed, final Speed rightSpeed)
         {
             return new LaneBias(new BySpeed(leftSpeed, rightSpeed), 2.0, Integer.MAX_VALUE);
         }
 
         /**
          * Returns a bias by speed with normal extent. Convenience km/h input.
          * @param leftSpeedKm double; desired speed for full left bias
          * @param rightSpeedKm double; desired speed for full right bias
          * @return bias by speed with normal extent
          */
         public static LaneBias bySpeed(final double leftSpeedKm, final double rightSpeedKm)
         {
             return bySpeed(new Speed(leftSpeedKm, SpeedUnit.KM_PER_HOUR), new Speed(rightSpeedKm, SpeedUnit.KM_PER_HOUR));
         }
 
         /** Provider of position on the road (0 = full left, 1 = full right). */
         private final RoadPosition roadPosition;
 
         /** Bias extent. */
         private final double bias;
 
         /** Number of lanes to consider in either direction, including the preferred lane. */
         private final double stickyLanes;
 
         /**
          * Constructor.
          * @param roadPosition RoadPosition; lateral position on the road (0 = right, 0.5 = middle, 1 = left)
          * @param bias double; bias extent, lower values create more spread traffic, 0.0 causes no lane preference
          * @param stickyLanes double; number of lanes to consider in either direction, including the preferred lane
          */
         public LaneBias(final RoadPosition roadPosition, final double bias, final double stickyLanes)
         {
             Throw.when(bias < 0.0, IllegalArgumentException.class, "Bias should be positive or 0.");
             Throw.when(stickyLanes < 1.0, IllegalArgumentException.class, "Sticky lanes should be 1.0 or larger.");
             this.roadPosition = roadPosition;
             this.bias = bias;
             this.stickyLanes = stickyLanes;
         }
 
         /**
          * Returns a random draw weight for given lane. The weight is calculated as:
          * 
          * <pre>
          * weight = { 0,                               d &gt;= number of sticky lanes
          *          { 1 / ((d + 1)^bias * (m + 1)),    otherwise
          * 
          * where,
          *      d:      lane deviation from lateral bias position
          *      bias:   bias extent
          *      m:      number of unplaced GTU's
          * </pre>
          * 
          * The formula makes sure that all lanes have equal weight for <i>bias</i> &#61; 0, given an equal number of unplaced
          * GTU's <i>m</i>. The bias can be seen to result in this: for each GTU on the 2nd lane, there are 2^(<i>bias</i> - 1)
          * GTU's on the 1st lane. In numbers: 1 vs. 1 for <i>bias</i> &#61; 0, 1 vs. 2 for <i>bias</i> &#61; 1, 1 vs. 4 for
          * <i>bias</i> &#61; 2, 1 vs. 8 for <i>bias</i> &#61; 3, etc.<br>
          * <br>
          * Division by <i>m</i> + 1 makes sure traffic distributes over the lanes in case of spillback, or otherwise too high
          * demand on a particular lane. The weight for lanes with more unplaced GTU's simply reduces. This effect balances out
          * with the bias, meaning that for a strong bias, GTU's are still likely to be generated on the biased lanes. Given a
          * relatively strong bias of <i>bias</i> &#61; 5, the weight for the 1st and 2nd lane becomes equal if the 2nd lane has
          * no unplaced GTU's, while the 1st lane has 31 unplaced GTU's.<br>
          * <br>
          * Lane deviation <i>d</i> is calculated as <i>d</i> &#61; abs(<i>latBiasLane</i> - <i>laneNumFromRight</i>). Here,
          * <i>latBiasLane</i> &#61; 1 + <i>roadPosition</i>*(<i>numberOfLanes</i> - 1), i.e. ranging from 1 to 4 on a 4-lane
          * road. For lanes that are beyond the number of sticky lanes, the weight is always 0.<br>
          * <br>
          * @param laneNumFromRight int; number of lane counted from right to left
          * @param numberOfLanes int; total number of lanes
          * @param numberOfUnplacedGTUs int; number of GTU's in the generation queue
          * @param desiredSpeed Speed; desired speed, possibly used to determine the biased road position
          * @return double; random draw weight for given lane
          */
         public double calculateWeight(final int laneNumFromRight, final int numberOfLanes, final int numberOfUnplacedGTUs,
                 final Speed desiredSpeed)
         {
             double d = Math.abs((1.0 + this.roadPosition.getValue(desiredSpeed) * (numberOfLanes - 1.0)) - laneNumFromRight);
             if (d >= this.stickyLanes)
             {
                 return 0.0;
             }
             return 1.0 / (Math.pow(d + 1.0, this.bias) * (numberOfUnplacedGTUs + 1.0));
         }
 
         /** {@inheritDoc} */
         @Override
         public int hashCode()
         {
             final int prime = 31;
             int result = 1;
             long temp;
             temp = Double.doubleToLongBits(this.bias);
             result = prime * result + (int) (temp ^ (temp >>> 32));
             result = prime * result + ((this.roadPosition == null) ? 0 : this.roadPosition.hashCode());
             temp = Double.doubleToLongBits(this.stickyLanes);
             result = prime * result + (int) (temp ^ (temp >>> 32));
             return result;
         }
 
         /** {@inheritDoc} */
         @Override
         public boolean equals(final Object obj)
         {
             if (this == obj)
             {
                 return true;
             }
             if (obj == null)
             {
                 return false;
             }
             if (getClass() != obj.getClass())
             {
                 return false;
             }
             LaneBias other = (LaneBias) obj;
             if (Double.doubleToLongBits(this.bias) != Double.doubleToLongBits(other.bias))
             {
                 return false;
             }
             if (this.roadPosition == null)
             {
                 if (other.roadPosition != null)
                 {
                     return false;
                 }
             }
             else if (!this.roadPosition.equals(other.roadPosition))
             {
                 return false;
             }
             if (Double.doubleToLongBits(this.stickyLanes) != Double.doubleToLongBits(other.stickyLanes))
             {
                 return false;
             }
             return true;
         }
 
         /** {@inheritDoc} */
         @Override
         public String toString()
         {
             return "Bias [roadPosition=" + this.roadPosition + ", bias=" + this.bias + ", stickyLanes=" + this.stickyLanes
                     + "]";
         }
 
     }
 
     /**
      * Interface for preferred road position for a lane bias.
      * <p>
      * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
      * <br>
      * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
      * </p>
      * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
      * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
      */
     public interface RoadPosition
     {
 
         /**
          * Returns the road position (0.0 = right, 1.0 = left).
          * @param desiredSpeed Speed; desired speed at the generator
          * @return road position (0.0 = right, 1.0 = left)
          */
         double getValue(Speed desiredSpeed);
 
         /**
          * Fixed road position.
          * <p>
          * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights
          * reserved. <br>
          * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
          * <p>
          * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
          * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
          * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
          */
         class ByValue implements RoadPosition
         {
 
             /** Road position. */
             private double value;
 
             /**
              * Constructor.
              * @param value double; road position
              */
             public ByValue(final double value)
             {
                 Throw.when(value < 0.0 || value > 1.0, IllegalArgumentException.class,
                         "Road position value should be in the range [0...1].");
                 this.value = value;
             }
 
             /** {@inheritDoc} */
             @Override
             public double getValue(final Speed desiredSpeed)
             {
                 return this.value;
             }
 
             /** {@inheritDoc} */
             @Override
             public int hashCode()
             {
                 final int prime = 31;
                 int result = 1;
                 long temp;
                 temp = Double.doubleToLongBits(this.value);
                 result = prime * result + (int) (temp ^ (temp >>> 32));
                 return result;
             }
 
             /** {@inheritDoc} */
             @Override
             public boolean equals(final Object obj)
             {
                 if (this == obj)
                 {
                     return true;
                 }
                 if (obj == null)
                 {
                     return false;
                 }
                 if (getClass() != obj.getClass())
                 {
                     return false;
                 }
                 ByValue other = (ByValue) obj;
                 if (Double.doubleToLongBits(this.value) != Double.doubleToLongBits(other.value))
                 {
                     return false;
                 }
                 return true;
             }
 
         }
 
         /**
          * Road position based on desired speed.
          * <p>
          * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights
          * reserved. <br>
          * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
          * <p>
          * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
          * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
          * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
          */
         class BySpeed implements RoadPosition
         {
 
             /** Desired speed at left side of the road. */
             private Speed leftSpeed;
 
             /** Desired speed at the right side of the road. */
             private Speed rightSpeed;
 
             /**
              * Constructor.
              * @param leftSpeed Speed; desired speed at left side of the road
              * @param rightSpeed Speed; desired speed at right side of the road
              */
             public BySpeed(final Speed leftSpeed, final Speed rightSpeed)
             {
                 Throw.when(leftSpeed.eq(rightSpeed), IllegalArgumentException.class,
                         "Left speed and right speed may not be equal. Use LaneBias.NONE.");
                 this.leftSpeed = leftSpeed;
                 this.rightSpeed = rightSpeed;
             }
 
             /** {@inheritDoc} */
             @Override
             public double getValue(final Speed desiredSpeed)
             {
                 Throw.whenNull(desiredSpeed, "Peeked desired speed from a strategical planner factory is null, "
                         + "while a lane bias depends on desired speed.");
                 double value = (desiredSpeed.si - this.rightSpeed.si) / (this.leftSpeed.si - this.rightSpeed.si);
                 return value < 0.0 ? 0.0 : (value > 1.0 ? 1.0 : value);
             }
 
             /** {@inheritDoc} */
             @Override
             public int hashCode()
             {
                 final int prime = 31;
                 int result = 1;
                 result = prime * result + ((this.leftSpeed == null) ? 0 : this.leftSpeed.hashCode());
                 result = prime * result + ((this.rightSpeed == null) ? 0 : this.rightSpeed.hashCode());
                 return result;
             }
 
             /** {@inheritDoc} */
             @Override
             public boolean equals(final Object obj)
             {
                 if (this == obj)
                 {
                     return true;
                 }
                 if (obj == null)
                 {
                     return false;
                 }
                 if (getClass() != obj.getClass())
                 {
                     return false;
                 }
                 BySpeed other = (BySpeed) obj;
                 if (this.leftSpeed == null)
                 {
                     if (other.leftSpeed != null)
                     {
                         return false;
                     }
                 }
                 else if (!this.leftSpeed.equals(other.leftSpeed))
                 {
                     return false;
                 }
                 if (this.rightSpeed == null)
                 {
                     if (other.rightSpeed != null)
                     {
                         return false;
                     }
                 }
                 else if (!this.rightSpeed.equals(other.rightSpeed))
                 {
                     return false;
                 }
                 return true;
             }
 
         }
 
     }
 
 }