////////////////////////////////////////////////////////////
public static PropositionalFormula operator &(PropositionalFormula x, PropositionalFormula y)
{
var result = new PropositionalFormula(x);
result.andWith(y);
return(result);
}
public PropositionalFormula(PropositionalFormula other)
: this()
{
foreach (var d in other.myDisjuncts)
{
myDisjuncts.Add(new Conjunction(d));
}
}
////////////////////////////////////////////////////////////
public void orWith(PropositionalFormula other)
{
if (ReferenceEquals(this, other))
{
return;
}
// Console.Write("{0} || {1}", this.ToString(), other.ToString());
bool b = isFalse || other.isFalse;
foreach (var c in other.myDisjuncts)
{
checkAddDisjunct(new Conjunction(c));
}
Debug.Assert(b || !isFalse);
// Console.WriteLine(" = {0}", this.ToString());
}
////////////////////////////////////////////////////////////
public void andWith(PropositionalFormula other)
{
List <Conjunction> oldDisjuncts = myDisjuncts;
myDisjuncts = new List <Conjunction>();
foreach (var cx in oldDisjuncts)
{
foreach (var cy in other.myDisjuncts)
{
Conjunction a = cx & cy;
if (a != null)
{
checkAddDisjunct(a);
}
}
}
}
public static PropositionalFormula or(IEnumerable <PropositionalFormula> others)
{
Debug.Assert(others != null);
// Debug.Assert(predecessors.Count > 0);
var result = new PropositionalFormula(false);
foreach (var o in others)
{
result.orWith(o);
}
/* if (predecessors.Count()==1)
* {
* var of = predecessors.First();
* var nof = !of;
* var nr = !result;
* Debug.Assert((result & nof).isFalse);
* Debug.Assert((nr & of).isFalse);
* Debug.Assert((result | nof).isTrue);
* Debug.Assert((nr | of ).isTrue);
* }
* */
return(result);
}
////////////////////////////////////////////////////////////
public static PropositionalFormula operator !(PropositionalFormula x)
{
// Console.WriteLine("!{0}", x.ToString());
PropositionalFormula result;
if (x.isTrue)
{
result = new PropositionalFormula(false);
}
else if (x.isFalse)
{
result = new PropositionalFormula(true);
}
else
{
result = new PropositionalFormula(false);
var indices = new int[x.myDisjuncts.Count];
for (int i = 0; i < indices.Length; i++)
{
indices[i] = 0;
}
do
{
{
var pos = new HashSet <int>();
var neg = new HashSet <int>();
for (int i = 0; i < indices.Length; i++)
{
Tuple <bool, int> t = x.disjuncts.ElementAt(i).conjuncts.ElementAt(indices[i]);
if (t.Item1)
{
neg.Add(t.Item2);
}
else
{
pos.Add(t.Item2);
}
}
if (pos.Intersect(neg).Count() == 0)
{
var disjunct = new Conjunction(pos, neg);
// Console.WriteLine("\t{0}", disjunct.ToString());
result.checkAddDisjunct(disjunct);
if (result.isTrue)
{
return(result);
}
}
}
int j = indices.Length - 1;
do
{
indices[j]++;
if (indices[j] < x.disjuncts.ElementAt(j).conjuncts.Count())
{
break;
}
if (j == 0)
{
break;
}
indices[j] = 0;
j--;
} while (true);
if (j == 0 && indices[j] == x.disjuncts.ElementAt(j).conjuncts.Count())
{
break;
}
} while (true);
// Console.WriteLine("{0} ==> {1}", x.ToString(), result.ToString());
}
/* {
* var m = (x & result);
* var b = (x | result);
* Debug.Assert(m.isFalse);
* Debug.Assert(b.isTrue);
* }*/
return(result);
}
