protected virtual bool FilterOutDomains(S current, ref bool[][] currentDomainsState, IVariableSelectionHeuristics <T, S> variableSelectionHeuristics)
{
bool reducedToZero = false;
var currentVariableConstraints = VariablesWithConstraints[current.Index].Item3;
for (int i = 0; i < currentVariableConstraints.Count; i++)
{
var pairVariable = VariablesWithConstraints[currentVariableConstraints[i].Id2].Item1;
var constraint = currentVariableConstraints[i];
if (variableSelectionHeuristics.IsBefore(current, pairVariable))
{
var pairVariableDomain = VariablesWithConstraints[pairVariable.Index].Item2;
var domainArray = pairVariableDomain.AsArray();
var domainMask = currentDomainsState[pairVariable.Index];
int domainSize = domainArray.Length;
for (int j = 0; j < domainSize; j++)
{
if (!constraint.Check(current.Value, domainArray[j]))
{
currentDomainsState[pairVariable.Index][j] = true;
domainSize--;
}
}
if (domainSize == 0)
{
reducedToZero = true;
break;
}
}
}
return(reducedToZero);
}
public virtual void BacktrackingAlgorithmForwardCheck(bool printSolutions = false)
{
int alreadySet = 0;
_timeToFirst = new Stopwatch();
_timeToComplete = new Stopwatch();
_foundSolutions = new List <S[]>();
S current = null;
bool backtrack = false;
_timeToFirst.Start();
_timeToComplete.Start();
var domainsStateStack = new Stack <bool[][]>();
bool[][] domainsState = new bool[VariablesWithConstraints.Length][];
for (int i = 0; i < VariablesWithConstraints.Length; i++)
{
domainsState[i] = new bool[VariablesWithConstraints[i].Item2.Size];
}
domainsStateStack.Push(domainsState);
bool[][] currentDomainsState = domainsStateStack.Peek();
Domain <T> currentVariableDomain = null;
while (true)
{
if (current == null)
{
current = _variableSelectionHeuristics.StartVariable();
}
else
{
if (backtrack)
{
if (_variableSelectionHeuristics.HasPrev())
{
current = _variableSelectionHeuristics.Prev();
backtrack = false;
domainsStateStack.Pop();
currentDomainsState = domainsStateStack.Peek();
}
else
{
_timeToComplete.Stop();
break;
}
}
else
{
if (_variableSelectionHeuristics.HasNext())
{
current = _variableSelectionHeuristics.Next();
}
else
{
_hasSolution = true;
if (_foundSolutionsNumber == 0)
{
_visitedNodesToFirst = _visitedNodes;
_timeToFirst.Stop();
_backtracksNumberToFirstSolution = _backtracksNumber;
}
_foundSolutionsNumber++;
_foundSolutions.Add(SaveSolution());
domainsStateStack.Pop();
domainsStateStack.Pop();
currentDomainsState = domainsStateStack.Peek();
currentVariableDomain = VariablesWithConstraints[current.Index].Item2;
current.Value = currentVariableDomain.Default;
current = _variableSelectionHeuristics.Prev();
_backtracksNumber++;
}
}
}
currentVariableDomain = VariablesWithConstraints[current.Index].Item2;
ValueSelectionHeuristics.RegisterDomain(current, currentVariableDomain, ref currentDomainsState[current.Index]);
bool constraintsSatisfied = false;
if (!ValueSelectionHeuristics.HasNext())
{
current.Value = currentVariableDomain.Default;
backtrack = true;
_backtracksNumber++;
}
else
{
while (ValueSelectionHeuristics.HasNext())
{
var currentDomainValue = ValueSelectionHeuristics.Next();
current.Value = currentDomainValue;
_visitedNodes++;
bool[][] temp = new bool[currentDomainsState.Length][];
int tempSize = temp.Length;
for (int i = 0; i < tempSize; i++)
{
if (_variableSelectionHeuristics.IsBefore(VariablesWithConstraints[i].Item1, current))
{
temp[i] = currentDomainsState[i];
}
else
{
int newSize = currentDomainsState[i].Length;
var tempArr = new bool[newSize];
temp[i] = new bool[newSize];
for (int j = 0; j < newSize; j++)
{
temp[i][j] = currentDomainsState[i][j];
}
}
}
domainsStateStack.Push(temp);
currentDomainsState = domainsStateStack.Peek();
if (!FilterOutDomains(current, ref currentDomainsState, _variableSelectionHeuristics))
{
constraintsSatisfied = true;
break;
}
domainsStateStack.Pop();
currentDomainsState = domainsStateStack.Peek();
_backtracksNumber++;
}
if (!constraintsSatisfied)
{
current.Value = currentVariableDomain.Default;
backtrack = true;
}
}
}
if (printSolutions)
{
PrintSolutionsInfo();
}
}