public ArithmeticLanguage CheckUnaryConstraints()
{
if (!constraint.isSatisfiable())
{
throw new PumpingLemmaException("Constraints of Arithmentic Language are not satisfiable");
}
//makes all constraints unary if possible and returns the resulting language
//throws PumpingLemmaException if not possible
HashSet <ComparisonExpression> allExpr = getComparisonExpressions(constraint);
HashSet <VariableType> VarsSeen = new HashSet <VariableType>();
HashSet <string> variables = new HashSet <string>();
//enumerate all variables
foreach (ComparisonExpression constr in allExpr)
{
HashSet <VariableType> varTypeSet = new HashSet <VariableType>(constr.arithmetic_operand1.GetVariables());
varTypeSet.UnionWith(constr.arithmetic_operand1.GetVariables());
foreach (VariableType t in varTypeSet)
{
variables.Add(t.ToString());
}
/*
* if (constr.arithmetic_operand1.GetVariables().Count == 1 || constr.arithmetic_operand2.GetVariables().Count > 1)
* {
*
* }
*/
if (constr.arithmetic_operand1.GetVariables().Count > 1 || constr.arithmetic_operand2.GetVariables().Count > 1)
{
throw new PumpingLemmaException("Cannot make constraints unary - several variables on one side of the comparison");
}
//if there it is an comparison with a constant, we are done
if (!constr.isUnary())
{
VariableType v1 = constr.arithmetic_operand1.GetVariables().First();
VariableType v2 = constr.arithmetic_operand2.GetVariables().First();
IEnumerable <ComparisonExpression> comparisonsContainingSecondVar = allExpr.Where(comp => comp.containsVariable(v2));
//try to substitute second variable
bool substituted = false;
foreach (ComparisonExpression cexp in comparisonsContainingSecondVar)
{
if (cexp.comparison_operator == ComparisonExpression.ComparisonOperator.EQ && cexp.isUnary())
{
//unfinished
}
}
}
}
foreach (string v in variables)
{
}
throw new NotImplementedException();
}
public static string NonRegularGetRandomWord(ArithmeticLanguage language, int n)
{
HashSet <Dictionary <VariableType, int> > usedAssigments = new HashSet <Dictionary <VariableType, int> >();
HashSet <VariableType> vars = language.constraint.GetVariables();
for (int i = 0; i < Math.Pow(n, vars.Count); i++)
{
Dictionary <VariableType, int> newAssigment = new Dictionary <VariableType, int>();
foreach (VariableType v in vars)
{
newAssigment.Add(v, randInt(0, n));
}
if (usedAssigments.Contains(newAssigment))
{
i--;
}
else
{
usedAssigments.Add(newAssigment);
//check sat
HashSet <BooleanExpression> ops = new HashSet <BooleanExpression>();
ops.Add(language.constraint);
foreach (var entry in newAssigment)
{
ops.Add(ComparisonExpression.Equal(LinearIntegerExpression.Variable(entry.Key.ToString()), entry.Value));
}
BooleanExpression expr = LogicalExpression.And(ops);
if (expr.isSatisfiable())
{
return(pumpedWord(language.symbolic_string, newAssigment));
}
}
}
return(wordError());
}