ttsolver.heuristics
Class PlacementSelection

java.lang.Object
  ttsolver.heuristics.PlacementSelection

All Implemented Interfaces:

ValueSelection

public class PlacementSelection
extends Object
implements ValueSelection

Placement (value) selection.

We have implemented a hierarchical handling of the value selection criteria (see HeuristicSelector).

The value selection heuristics also allow for random selection of a value with a given probability (random walk, e.g., 2%) and, in the case of MPP, to select the initial value (if it exists) with a given probability (e.g., 70%).

Parameters (general):

Parameter	Type	Comment
Placement.RandomWalkProb	Double	Random walk probability
Placement.GoodSelectionProb	Double	Good value (not removed from domain) selection probability (MAC related)
Placement.TabuLength	Integer	Tabu-list length (-1 means do not use tabu-list)
Placement.MPP_InitialProb	Double	MPP initial selection probability
Placement.MPP_Limit	Integer	MPP: limit on the number of perturbations (-1 for no limit)
Placement.MPP_PenaltyLimit	Double	MPP: limit on the perturbations penalty (-1 for no limit)

Parameters (for each level of selection):

Parameter	Type	Comment
Placement.NrAssignmentsWeight1 Placement.NrAssignmentsWeight2 Placement.NrAssignmentsWeight3	Double	Number of previous assignments of the value weight
Placement.NrConflictsWeight1,2,3	Double	Number of conflicts weight
Placement.WeightedConflictsWeight1,2,3	Double	Weighted conflicts weight (Conflict-based Statistics related)
Placement.NrPotentialConflictsWeight1,2,3	Double	Number of potential conflicts weight (Conflict-based Statistics related)
Placement.MPP_DeltaInitialAssignmentWeight1,2,3	Double	Delta initial assigments weight (MPP, violated initials related)
Placement.NrHardStudConfsWeight1,2,3	Double	Hard student conflicts weight (student conflicts between single-section classes)
Placement.NrStudConfsWeight1,2,3	Double	Student conflicts weight
Placement.TimePreferenceWeight1,2,3	Double	Time preference weight
Placement.DeltaTimePreferenceWeight1,2,3	Double	Time preference delta weight (difference between before and after assignemnt of the value)
Placement.ConstrPreferenceWeight1,2,3	Double	Constraint preference weight
Placement.RoomPreferenceWeight1,2,3	Double	Room preference weight
Placement.UselessSlotsWeight1,2,3	Double	Useless slot weight
Placement.TooBigRoomWeight1,2,3	Double	Too big room weight
Placement.DistanceInstructorPreferenceWeight1,2,3	Double	Distance (of the rooms of the back-to-back classes) based instructor preferences weight
Placement.DeptSpreadPenaltyWeight1,2,3	Double	Department spreading: penalty of when a slot over initial allowance is used
Placement.ThresholdKoef1,2	Double	Threshold koeficient of the level

Version:

1.0

Author:

Tomáš Müller

See Also:

PlacementSelection

Field Summary

static String	DELTA_INITIAL_ASSIGNMENT_WEIGHT
static String	DELTA_TIME_PREFERENCE_WEIGHT
static String	DEPT_SPREAD_WEIGHT
static String	DISTANCE_INSTRUCTOR_PREFERENCE_WEIGHT
static String	GOOD_SELECTION_PROB
static String	INITIAL_SELECTION_PROB
static String	NR_ASSIGNMENTS_WEIGHT
static String	NR_CONFLICTS_WEIGHT
static String	NR_HARD_STUDENT_CONF_WEIGHT
static String	NR_MPP_LIMIT
static String	NR_MPP_PENALTY_LIMIT
static String	NR_POTENTIAL_CONFLICTS_WEIGHT
static String	NR_STUDENT_CONF_WEIGHT
static String	NR_THRESHOLD_KOEF
static String	RW_SELECTION_PROB
static String	SUM_CONSTR_PREFERENCE_WEIGHT
static String	SUM_ROOM_PREFERENCE_WEIGHT
static String	SUM_TIME_PREFERENCE_WEIGHT
static String	TABU_LENGTH
static String	TOO_BIG_ROOM_WEIGHT
static String	USELESS_SLOTS_WEIGHT
static String	WEIGHTED_CONFLICTS_WEIGHT

Constructor Summary

PlacementSelection(DataProperties properties)

Method Summary

void	init(Solver solver) Initialization
static Vector	parameters()
Value	selectValue(Solution solution, Variable selectedVariable) Value selection

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

GOOD_SELECTION_PROB

public static final String GOOD_SELECTION_PROB

See Also:

Constant Field Values

RW_SELECTION_PROB

public static final String RW_SELECTION_PROB

See Also:

Constant Field Values

INITIAL_SELECTION_PROB

public static final String INITIAL_SELECTION_PROB

See Also:

Constant Field Values

NR_MPP_LIMIT

public static final String NR_MPP_LIMIT

See Also:

Constant Field Values

NR_MPP_PENALTY_LIMIT

public static final String NR_MPP_PENALTY_LIMIT

See Also:

Constant Field Values

NR_CONFLICTS_WEIGHT

public static final String NR_CONFLICTS_WEIGHT

See Also:

Constant Field Values

NR_POTENTIAL_CONFLICTS_WEIGHT

public static final String NR_POTENTIAL_CONFLICTS_WEIGHT

See Also:

Constant Field Values

WEIGHTED_CONFLICTS_WEIGHT

public static final String WEIGHTED_CONFLICTS_WEIGHT

See Also:

Constant Field Values

DELTA_TIME_PREFERENCE_WEIGHT

public static final String DELTA_TIME_PREFERENCE_WEIGHT

See Also:

Constant Field Values

DELTA_INITIAL_ASSIGNMENT_WEIGHT

public static final String DELTA_INITIAL_ASSIGNMENT_WEIGHT

See Also:

Constant Field Values

NR_STUDENT_CONF_WEIGHT

public static final String NR_STUDENT_CONF_WEIGHT

See Also:

Constant Field Values

NR_HARD_STUDENT_CONF_WEIGHT

public static final String NR_HARD_STUDENT_CONF_WEIGHT

See Also:

Constant Field Values

USELESS_SLOTS_WEIGHT

public static final String USELESS_SLOTS_WEIGHT

See Also:

Constant Field Values

SUM_CONSTR_PREFERENCE_WEIGHT

public static final String SUM_CONSTR_PREFERENCE_WEIGHT

See Also:

Constant Field Values

SUM_ROOM_PREFERENCE_WEIGHT

public static final String SUM_ROOM_PREFERENCE_WEIGHT

See Also:

Constant Field Values

SUM_TIME_PREFERENCE_WEIGHT

public static final String SUM_TIME_PREFERENCE_WEIGHT

See Also:

Constant Field Values

NR_ASSIGNMENTS_WEIGHT

public static final String NR_ASSIGNMENTS_WEIGHT

See Also:

Constant Field Values

NR_THRESHOLD_KOEF

public static final String NR_THRESHOLD_KOEF

See Also:

Constant Field Values

TOO_BIG_ROOM_WEIGHT

public static final String TOO_BIG_ROOM_WEIGHT

See Also:

Constant Field Values

DEPT_SPREAD_WEIGHT

public static final String DEPT_SPREAD_WEIGHT

See Also:

Constant Field Values

DISTANCE_INSTRUCTOR_PREFERENCE_WEIGHT

public static final String DISTANCE_INSTRUCTOR_PREFERENCE_WEIGHT

See Also:

Constant Field Values

TABU_LENGTH

public static final String TABU_LENGTH

See Also:

Constant Field Values

Constructor Detail

PlacementSelection

public PlacementSelection(DataProperties properties)

Method Detail

parameters

public static Vector parameters()

init

public void init(Solver solver)

Description copied from interface: ValueSelection

Initialization

Specified by:

init in interface ValueSelection

selectValue

public Value selectValue(Solution solution,
                         Variable selectedVariable)

Description copied from interface: ValueSelection

Value selection

Specified by:

selectValue in interface ValueSelection

Parameters:

solution - current solution

selectedVariable - selected variable