/*
A -> (N v Q)
~(N v ~A)
A -> Q (conclusion)
*/
func SatValid(t *testing.T) {
a := literal.Literal{"A", false}
na := a.Negation()
n := literal.Literal{"N", false}
nn := n.Negation()
q := literal.Literal{"Q", false}
nq := q.Negation()
one := clause.Clause{}
one.Append(a)
two := clause.Clause{}
two.Append(nq)
three := clause.Clause{}
three.Append(nn)
four := clause.Clause{}
four.Append(na)
four.Append(n)
four.Append(q)
CS := clauseset.ClauseSet{}
CS.Append(one)
CS.Append(two)
CS.Append(three)
CS.Append(four)
sat, _ := Satisfiable(CS)
if sat {
t.Errorf("ClauseSet %q was Satisfiable, so it is an invalid argument (it should be valid)", CS)
}
}
//Reduce transforms S by removing any clauses that contain the literal L1
// and removing L2 (i.e. ~L1) from any clauses that contain it
func (c ClauseSet) Reduce(l1 literal.Literal) ClauseSet {
cs := c.Copy()
l2 := l1.Negation()
newClauseSet := ClauseSet{}
for _, clause := range cs.clauses {
i := clause.Contains(l1)
if i != -1 {
continue
}
j := clause.Contains(l2)
if j != -1 {
clause.RemoveIndex(j)
}
//tautological elemination
if !clause.Tautology() {
newClauseSet.Append(clause)
}
}
return newClauseSet
}
