public override Element /*!*/ Constrain(Element /*!*/ e, IExpr /*!*/ expr)
{
//Contract.Requires(expr != null);
//Contract.Requires(e != null);
Contract.Ensures(Contract.Result <Element>() != null);
log.DbgMsg(string.Format("Constraining with {0} into {1} ...", expr, this.ToString(e)));
PolyhedraLatticeElement ple = (PolyhedraLatticeElement)e;
if (ple.lcs.IsBottom())
{
return(ple);
}
LinearCondition le = LinearExpressionBuilder.AsCondition(expr);
if (le != null)
{
// update the polyhedron according to the linear expression
Contract.Assume(ple.lcs.Constraints != null);
ArrayList /*LinearConstraint*/ clist = (ArrayList /*!*/ /*LinearConstraint*/)cce.NonNull(ple.lcs.Constraints.Clone());
le.AddToConstraintSystem(clist);
LinearConstraintSystem newLcs = new LinearConstraintSystem(clist);
return(new PolyhedraLatticeElement(newLcs));
}
return(ple);
}
public override Answer CheckVariableDisequality(Element /*!*/ e, IVariable /*!*/ var1, IVariable /*!*/ var2)
{
//Contract.Requires(var2 != null);
//Contract.Requires(var1 != null);
//Contract.Requires(e != null);
PolyhedraLatticeElement /*!*/ ple = (PolyhedraLatticeElement)cce.NonNull(e);
Contract.Assume(ple.lcs.Constraints != null);
ArrayList /*LinearConstraint!*//*!*/ clist = (ArrayList /*LinearConstraint!*/)cce.NonNull(ple.lcs.Constraints.Clone());
LinearConstraint /*!*/ lc = new LinearConstraint(LinearConstraint.ConstraintRelation.EQ);
Contract.Assert(lc != null);
lc.SetCoefficient(var1, Rational.ONE);
lc.SetCoefficient(var2, Rational.MINUS_ONE);
clist.Add(lc);
LinearConstraintSystem newLcs = new LinearConstraintSystem(clist);
if (newLcs.IsBottom())
{
return(Answer.Yes);
}
else
{
return(Answer.Maybe);
}
}
/// <summary>
/// Creates a top or bottom elements, according to parameter "top".
/// </summary>
public PolyhedraLatticeElement(bool top)
{
if (top)
{
lcs = new LinearConstraintSystem(new ArrayList/*LinearConstraint*/ ());
}
else
{
lcs = new LinearConstraintSystem();
}
}
public override Lattice.Element /*!*/ Widen(Element /*!*/ first, Element /*!*/ second)
{
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result <Lattice.Element>() != null);
log.DbgMsg("Widening ...");
log.DbgMsgIndent();
PolyhedraLatticeElement aa = (PolyhedraLatticeElement)first;
PolyhedraLatticeElement bb = (PolyhedraLatticeElement)second;
LinearConstraintSystem lcs = aa.lcs.Widen(bb.lcs);
PolyhedraLatticeElement result = new PolyhedraLatticeElement(lcs);
log.DbgMsg(string.Format("{0} |_| {1} --> {2}", this.ToString(first), this.ToString(second), this.ToString(result)));
log.DbgMsgUnindent();
return(result);
}
public PolyhedraLatticeElement(LinearConstraintSystem /*!*/ lcs)
{
Contract.Requires(lcs != null);
this.lcs = lcs;
}
