/// <summary>
/// Get corresponding Z3 formula of a MSF row.
/// </summary>
/// <param name="rid">The MSF row id</param>
private ArithExpr MkGoalRow(int rid)
{
// Start with the 0 term
List <ArithExpr> row = new List <ArithExpr>();
// Now, add all the entries of this row
foreach (LinearEntry entry in GetRowEntries(rid))
{
// Get the variable and constant in the row
ArithExpr e = _solver.GetVariable(entry.Index);
if (!entry.Value.IsOne)
{
e = _solver.Context.MkMul(_solver.GetNumeral(entry.Value, e.Sort), e);
}
row.Add(e);
}
switch (row.Count)
{
case 0: return(_solver.GetNumeral(new Rational()));
case 1: return(row[0]);
default: return(_solver.Context.MkAdd(row.ToArray()));
}
}
private BoolExpr MkBool(int rid)
{
var context = _solver.Context;
if (IsConstant(rid))
{
Rational lower, upper;
GetBounds(rid, out lower, out upper);
Debug.Assert(lower == upper);
if (lower.IsZero)
{
return(context.MkFalse());
}
return(context.MkTrue());
}
if (IsOperation(rid))
{
BoolExpr[] children;
ArithExpr[] operands;
TermModelOperation op = GetOperation(rid);
switch (op)
{
case TermModelOperation.And:
Debug.Assert(GetOperandCount(rid) >= 2, "Conjunction requires at least two operands.");
children = (GetOperands(rid)).Select(x => MkBool(x)).ToArray();
return(context.MkAnd(children));
case TermModelOperation.Or:
Debug.Assert(GetOperandCount(rid) >= 2, "Disjunction requires at least two operands.");
children = (GetOperands(rid)).Select(x => MkBool(x)).ToArray();
return(context.MkOr(children));
case TermModelOperation.Not:
Debug.Assert(GetOperandCount(rid) == 1, "Negation is unary.");
return(context.MkNot(MkBool(GetOperand(rid, 0))));
case TermModelOperation.If:
Debug.Assert(GetOperandCount(rid) == 3, "If is ternary.");
BoolExpr b = MkBool(GetOperand(rid, 0));
Expr x1 = MkBool(GetOperand(rid, 1));
Expr x2 = MkBool(GetOperand(rid, 2));
return((BoolExpr)context.MkITE(b, x1, x2));
case TermModelOperation.Unequal:
Debug.Assert(GetOperandCount(rid) >= 2, "Distinct should have at least two operands.");
return(context.MkDistinct((GetOperands(rid)).Select(x => MkTerm(x)).ToArray()));
case TermModelOperation.Greater:
case TermModelOperation.Less:
case TermModelOperation.GreaterEqual:
case TermModelOperation.LessEqual:
case TermModelOperation.Equal:
Debug.Assert(GetOperandCount(rid) >= 2, "Comparison should have at least two operands.");
operands = (GetOperands(rid)).Select(x => MkTerm(x)).ToArray();
return(ReduceComparison(GetOperation(rid), operands));
case TermModelOperation.Identity:
Debug.Assert(GetOperandCount(rid) == 1, "Identity takes exactly one operand.");
return(MkBool(GetOperand(rid, 0)));
default:
return(context.MkEq(MkTerm(rid), _solver.GetNumeral(Rational.One)));
}
}
return(context.MkEq(MkTerm(rid), _solver.GetNumeral(Rational.One)));
}