/// <summary>
/// Given an array of predidates {p_1, p_2, ..., p_n} where n>=0,
/// enumerate all satisfiable Boolean combinations Tuple({b_1, b_2, ..., b_n}, p)
/// where p is satisfiable and equivalent to p'_1 & p'_2 & ... & p'_n,
/// where p'_i = p_i if b_i = true and p'_i is Not(p_i). Otherwise, if n=0
/// return Tuple({},True).
/// </summary>
/// <param name="preds">array of predicates</param>
/// <returns>all minterms of the given predicate sequence</returns>
public List <TPredicate> GenerateMinterms(params TPredicate[] preds)
{
if (preds.Length == 0)
{
return(new List <TPredicate> {
_algebra.True
});
}
// The minterms will be solved using non-equivalent predicates, i.e., the equivalence classes of preds. The
// following code maps each predicate to an equivalence class and also stores for each equivalence class the
// predicates belonging to it, so that a valuation for the original predicates may be reconstructed.
var tree = new PartitionTree(_algebra);
var seen = new HashSet <EquivalenceClass>();
for (int i = 0; i < preds.Length; i++)
{
// Use a wrapper that overloads Equals to be logical equivalence as the key
if (seen.Add(new EquivalenceClass(_algebra, preds[i])))
{
// Push each equivalence class into the partition tree
tree.Refine(preds[i]);
}
}
// Return all minterms as the leaves of the partition tree
return(tree.GetLeafPredicates());
}
/// <summary>
/// Given an array of predidates {p_1, p_2, ..., p_n} where n>=0,
/// enumerate all satisfiable Boolean combinations Tuple({b_1, b_2, ..., b_n}, p)
/// where p is satisfiable and equivalent to p'_1 & p'_2 & ... & p'_n,
/// where p'_i = p_i if b_i = true and p'_i is Not(p_i). Otherwise, if n=0
/// return Tuple({},True).
/// </summary>
/// <param name="preds">array of predicates</param>
/// <returns>all minterms of the given predicate sequence</returns>
public List <TPredicate> GenerateMinterms(IEnumerable <TPredicate> preds)
{
var tree = new PartitionTree(_algebra.True);
foreach (TPredicate pred in preds)
{
// Push each predicate into the partition tree
tree.Refine(_algebra, pred);
}
// Return all minterms as the leaves of the partition tree
return(tree.GetLeafPredicates());
}