public static Expr toExpr(List<List<Expr>> ors) {
List<Expr> tmpOrs = new ArrayList<Expr>();
for (List<Expr> ands : ors) {
Expr and = ExprUtils.andifyBalanced(ands);
tmpOrs.add(and);
}
if (ors.size() == 0) {
return NodeValue.FALSE;
}
Expr result = ExprUtils.orifyBalanced(tmpOrs);
return result;
}
// FIXME This method removes redundant TRUEs from clauses
public static Expr dnfToExpr(Set<Set<Expr>> dnf, boolean skipUnsatisfiable) {
Set<Expr> exprs = new HashSet<Expr>();
for (Set<Expr> clause : dnf) {
if (clause.size() > 1 && clause.contains(NodeValue.TRUE)) {
clause.remove(NodeValue.TRUE);
}
if (skipUnsatisfiable) {
if (!ClauseUtils.isSatisfiable(clause)) {
continue;
}
}
exprs.add(ExprUtils.andifyBalanced(clause));
}
Expr result = ExprUtils.orifyBalanced(exprs);
return result != null ? result : NodeValue.FALSE;
}
/**
* For each clause determine the constant constraints, and return those, that are common to all
* clauses.
*
* @param dnf
*/
public static Map<Var, NodeValue> extractConstantConstraints(Set<Set<Expr>> dnf) {
Map<Var, NodeValue> result = new HashMap<Var, NodeValue>();
Iterator<Set<Expr>> clauseIt = dnf.iterator();
if (!clauseIt.hasNext()) {
return result;
}
Set<Expr> firstClause = clauseIt.next();
for (Expr expr : firstClause) {
Pair<Var, NodeValue> constraint = ExprUtils.extractConstantConstraint(expr);
addConstantConstraint(result, constraint);
}
Set<Var> seenVars = new HashSet<Var>();
while (clauseIt.hasNext()) {
if (result.isEmpty()) {
return result;
}
Set<Expr> clause = clauseIt.next();
for (Expr expr : clause) {
Pair<Var, NodeValue> constraint = ExprUtils.extractConstantConstraint(expr);
if (constraint == null || !result.containsKey(constraint.getKey())) {
continue;
}
addConstantConstraint(result, constraint);
seenVars.add(constraint.getKey());
}
result.keySet().retainAll(seenVars);
seenVars.clear();
}
return result;
}
public SortCondition(Node var, int dir) {
this(ExprUtils.nodeToExpr(var), dir);
}
public static List<ExprList> toClauses(ExprList exprs) {
Expr evaluated = eval(ExprUtils.andifyBalanced(exprs));
return evaluated == null ? null : dnfToClauses(Collections.singleton(evaluated));
}
