public Assignment(Variable var,OverFloorType val)
{
this.variable = var;
this.value = val;
this.nConflicts = 0;
domainPrune = new Dictionary<Vector2, List<OverFloorType>> ();
}
private static List<OverFloorType> MAC3HeadTailChecker(Variable headVar, Variable tailVar, CSP problem)
{
var ret = new List<OverFloorType>();
//Loop remaining domain values
var remainingDomains = tailVar.remDomain.ToList();
foreach (var remDomTail in remainingDomains)
{
int validTailValue = 0;
problem.AssignValue(tailVar, remDomTail, false);
var remDomainHead = headVar.remDomain.ToList();
foreach (var remDomHead in remDomainHead)
{
var alreadyAssigned = problem.IsVariableAssigned(headVar);
if(!alreadyAssigned)problem.AssignValue(headVar, remDomHead, false);
bool valid = problem.ValidateConstraints();
if (!valid)
{
validTailValue++;
break;
}
if (!alreadyAssigned) problem.RemoveValue(headVar);
}
if (validTailValue == remDomainHead.Count())
ret.Add(remDomTail);
problem.RemoveValue(tailVar);
}
return ret;
}
/// <summary>
/// Removes an assignment and recover pruned variables
/// </summary>
/// <param name="var">Removes the assignment for this variable and adds pruned variables.</param>
public void RemoveValue(Variable var)
{
Vector2 varPos = var.pos;
Assignment assign = assignments.First (a => a.variable.pos == varPos);
foreach (var varPrune in assign.domainPrune.Keys) {
List<OverFloorType> valuesPruned = assign.domainPrune[varPrune];
Variable varToUnprune = vars.First(v=>v.pos == varPrune);
foreach(var vPrune in valuesPruned)
{
varToUnprune.addDomainElement(vPrune);
}
}
assignments.Remove (assign);
}
/// <summary>
/// Removes a available value from a variable
/// </summary>
/// <param name="var"></param>
/// <param name="value"></param>
public void RemoveDomainElementFromVariable(Variable var, OverFloorType value)
{
this.vars.First(v=>v.pos == var.pos).removeDomainElement(value);
}
/// <summary>
/// Return the value that will restrict less the assignment of future variables
/// </summary>
/// <param name="var">Variable to get possible assignments from</param>
/// <returns>List with all possible assignments for the variable order by least restraining value</returns>
public List<Assignment> OrderAssignmentsByLeastRestrictingValues(Variable var)
{
List<Assignment> remAssignments = new List<Assignment>();
foreach (var remValue in var.remDomain)
{
remAssignments.Add(new Assignment(var, remValue));
}
remAssignments.ForEach(a => a.nConflicts = ConflictAssignment(a));
return remAssignments.Where(a => a.validAssignment).OrderByDescending(a => a.nConflicts).ToList();
}
/// <summary>
/// Return if a variable has some assignment
/// </summary>
/// <param name="var"></param>
/// <returns></returns>
public bool IsVariableAssigned(Variable var)
{
return assignments.Any(a => a.variable.pos == var.pos);
}
public OverFloorType GetVariableValue(Variable var)
{
return assignments.FirstOrDefault(a => a.variable.pos == var.pos).value;
}
/// <summary>
/// Return the list of neighbours of a variable
/// </summary>
/// <param name="var">Variable to get neighbours from</param>
/// <returns>List of neighbours</returns>
public List<Variable> GetNeighbours(Variable var)
{
return neighbours[var.pos];
}
/// <summary>
/// Creates the assignment and prunes other variables
/// </summary>
/// <param name="var">Variable.</param>
/// <param name="val">Value.</param>
/// <returns>True if the assignment is legal</returns>
public bool AssignValue(Variable var,OverFloorType val, bool inference = true)
{
//Create a new assignment
Assignment assign = new Assignment (var, val);
//Get current domain before MAC3 to store posible values to prune
List<OverFloorType> domainBeformMAC = var.remDomain.ToList();
//Get variable prunes
var validAssignment = true;
if (inference)
validAssignment = Search.MAC3(ref assign, new CSP(this) );
if (validAssignment)
{
//Prune all values that are not a variable
assign.domainPrune.Add(var.pos, domainBeformMAC.Where(r => r != val).ToList());
//Go over variable domain prunes to remove from variables
foreach (var varPrune in assign.domainPrune.Keys)
{
List<OverFloorType> valuesToPrune = assign.domainPrune[varPrune];
Variable varToPrune = vars.First(v => v.pos == varPrune);
foreach (var vPrune in valuesToPrune)
{
varToPrune.removeDomainElement(vPrune);
}
}
//Save the assignment
assignments.Add(assign);
}
return validAssignment;
}
