// --------------------------------------------------------------------------------------------------------
// ------------------ support routines --------------------------------------------------------------------
// --------------------------------------------------------------------------------------------------------
/// <summary>
/// Returns a set of constraints that is the given set of constraints with dimension "dim"
/// projected out. See Cousot and Halbwachs, section 3.3.1.1.
/// </summary>
/// <param name="dim"></param>
/// <param name="constraints"></param>
/// <returns></returns>
static ArrayList /*LinearConstraint!*//*!*/ Project(IVariable/*!*/ dim, ArrayList /*LinearConstraint!*//*!*/ constraints) {
Contract.Requires(constraints != null);
Contract.Requires(dim != null);
Contract.Ensures(Contract.Result<ArrayList>() != null);
// Sort the inequality constaints into ones where dimension "dim" is 0, negative, and
// positive, respectively. Put equality constraints with a non-0 "dim" into "eq".
ArrayList /*LinearConstraint!*//*!*/ final = new ArrayList /*LinearConstraint!*/ ();
ArrayList /*LinearConstraint!*//*!*/ negative = new ArrayList /*LinearConstraint!*/ ();
ArrayList /*LinearConstraint!*//*!*/ positive = new ArrayList /*LinearConstraint!*/ ();
ArrayList /*LinearConstraint!*//*!*/ eq = new ArrayList /*LinearConstraint!*/ ();
foreach (LinearConstraint/*!*/ cc in constraints) {
Contract.Assert(cc != null);
Rational coeff = cc[dim];
if (coeff.IsZero) {
LinearConstraint lc = cce.NonNull(cc.Clone());
if (!lc.IsConstant()) {
lc.RemoveDimension(dim);
final.Add(lc);
}
} else if (cc.Relation == LinearConstraint.ConstraintRelation.EQ) {
eq.Add(cc);
} else if (coeff.IsNegative) {
negative.Add(cc);
} else {
System.Diagnostics.Debug.Assert(coeff.IsPositive);
positive.Add(cc);
}
}
if (eq.Count != 0) {
LinearConstraint eqConstraint = (LinearConstraint/*!*/)cce.NonNull(eq[eq.Count - 1]);
eq.RemoveAt(eq.Count - 1);
Rational eqC = -eqConstraint[dim];
foreach (ArrayList /*LinearConstraint!*/ list in new ArrayList[] { eq, negative, positive }) {
Contract.Assert(list != null);
foreach (LinearConstraint/*!*/ lcX in list) {
Contract.Assert(lcX != null);
LinearConstraint lc = cce.NonNull(lcX.Clone());
lc.AddMultiple(lc[dim] / eqC, eqConstraint);
System.Diagnostics.Debug.Assert(lc[dim].IsZero);
if (!lc.IsConstant()) {
lc.RemoveDimension(dim);
final.Add(lc);
} else {
System.Diagnostics.Debug.Assert(lc.IsConstantSatisfiable());
}
}
}
} else {
// Consider all pairs of constraints with (negative,positive) coefficients of "dim".
foreach (LinearConstraint/*!*/ cn in negative) {
Contract.Assert(cn != null);
Rational dn = -cn[dim];
System.Diagnostics.Debug.Assert(dn.IsNonNegative);
foreach (LinearConstraint/*!*/ cp in positive) {
Contract.Assert(cp != null);
Rational dp = cp[dim];
LinearConstraint lc = new LinearConstraint(LinearConstraint.ConstraintRelation.LE);
lc.AddMultiple(dn, cp);
lc.AddMultiple(dp, cn);
System.Diagnostics.Debug.Assert(lc[dim].IsZero);
if (!lc.IsConstant()) {
lc.RemoveDimension(dim);
final.Add(lc);
} else {
System.Diagnostics.Debug.Assert(lc.IsConstantSatisfiable());
}
}
}
}
return final;
}
public LinearConstraintSystem(ArrayList /*LinearConstraint!*//*!*/ cs) {
Contract.Requires(cs != null);
#if BUG_159_HAS_BEEN_FIXED
Contract.Requires(Contract.ForAll(cs) , cc=> cc.coefficients.Count != 0);
#endif
ArrayList constraints = new ArrayList /*LinearConstraint!*/ (cs.Count);
foreach (LinearConstraint/*!*/ cc in cs) {
Contract.Assert(cc != null);
constraints.Add(cc);
}
Constraints = constraints;
FrameDimensions = new HashSet /*IVariable!*/ (); // to please compiler; this value will be overridden in the call to GenerateFrameConstraints below
//:base();
GenerateFrameFromConstraints();
SimplifyConstraints();
CheckInvariant();
#if DEBUG_PRINT
Console.WriteLine("LinearConstraintSystem: constructor produced:");
Dump();
#endif
}
LinearConstraintSystem(FrameElement/*!*/ v) {
Contract.Requires(v != null);
IMutableSet/*!*/ frameDims = v.GetDefinedDimensions();
Contract.Assert(frameDims != null);
ArrayList /*LinearConstraint!*/ constraints = new ArrayList /*LinearConstraint!*/ ();
foreach (IVariable/*!*/ dim in frameDims) {
Contract.Assert(dim != null);
LinearConstraint lc = new LinearConstraint(LinearConstraint.ConstraintRelation.EQ);
lc.SetCoefficient(dim, Rational.ONE);
lc.rhs = v[dim];
constraints.Add(lc);
}
FrameDimensions = frameDims;
Constraints = constraints;
ArrayList /*FrameElement*/ frameVertices = new ArrayList /*FrameElement*/ ();
frameVertices.Add(v);
FrameVertices = frameVertices;
FrameRays = new ArrayList /*FrameElement*/ ();
FrameLines = new ArrayList /*FrameElement*/ ();
//:base();
CheckInvariant();
}
