/*
A -> B
~A
~B (conclusion)
*/
func SatInvalid(t *testing.T) {
na := literal.Literal{"A", true}
b := literal.Literal{"B", false}
one := clause.Clause{}
one.Append(na)
two := clause.Clause{}
two.Append(b)
three := clause.Clause{}
three.Append(na)
three.Append(b)
CS := clauseset.ClauseSet{}
CS.Append(one)
CS.Append(two)
CS.Append(three)
CS.Indent = 0
sat, _ := Satisfiable(CS)
if !sat {
t.Errorf("ClauseSet %q was not Satisfiable, so it is a valid argument (it should be invalid)", CS)
}
}
//Satisfiable implements above function
func Satisfiable(CS clauseset.ClauseSet) (bool, Tree) {
tree := Tree{Name: CS.String(), Split: ""}
fmt.Printf("\n%sSatisfiable(%s)\n", strings.Repeat(" ", CS.Indent), CS)
CS.Indent += 2
//if CS = {} : return true
if CS.Len() == 0 {
fmt.Printf("%sEmpty ClauseSet, returning true\n", strings.Repeat(" ", CS.Indent))
openTree := Tree{Name: "O", Split: ""}
tree.Children = append(tree.Children, openTree)
return true, tree
}
//if {} in CS : return false
firstElement, err := CS.FirstElement()
if err != nil {
log.Fatal(err)
}
if clause.Len(firstElement) == 0 {
fmt.Printf("%s{} found in ClauseSet, returning false\n", strings.Repeat(" ", CS.Indent))
closedTree := Tree{Name: "X", Split: ""}
tree.Children = append(tree.Children, closedTree)
return false, tree
}
//select L in lit(CS): return Satisfiable(CS_L) || Satisfiable(CS_L')
nextLiteral, err2 := CS.NextLiteral()
if err2 != nil {
log.Fatal(err2)
}
fmt.Printf("%sSpliting on %s\n", strings.Repeat(" ", CS.Indent), nextLiteral)
CSL := CS.Reduce(nextLiteral)
CSL.Indent = CS.Indent
CSR := CS.Reduce(nextLiteral.Negation())
CSR.Indent = CS.Indent
left, tree_l := Satisfiable(CSL)
right, tree_r := Satisfiable(CSR)
tree_l.Split = nextLiteral.String()
tree_r.Split = nextLiteral.Negation().String()
tree.Children = append(tree.Children, tree_l)
tree.Children = append(tree.Children, tree_r)
return left || right, tree
}
//FindValidity finds the validity of the argument (given as a ClauseSet)
func FindValidity(CS clauseset.ClauseSet, filename string) {
fmt.Printf("Starting ClauseSet: %s\n", CS)
CS.Indent = 0
sat, tree := Satisfiable(CS)
treeJson, _ := json.Marshal(tree)
f, _ := os.Create(filename)
f.WriteString(string(treeJson))
fmt.Print("Conclusion: ")
if sat {
fmt.Printf("Satisfiable(%s) == %t; INVALID\n", CS, sat)
} else {
fmt.Printf("Satisfiable(%s) == %t; VALID\n", CS, sat)
}
}
