internal void Solve(Z3BaseParams parameters, IEnumerable <IGoal> modelGoals,
Action <int> addRow, Func <int, ArithExpr> mkGoalRow, Action <Z3Result> setResult)
{
_variables.Clear();
_goals.Clear();
try
{
// Mark that we are in solving phase
_isSolving = true;
// Construct Z3
ConstructSolver(parameters);
// Add all the variables
foreach (int vid in _model.VariableIndices)
{
AddVariable(vid);
}
// Add all the rows
foreach (int rid in _model.RowIndices)
{
addRow(rid);
}
// Add enabled goals to optimization problem
foreach (IGoal g in modelGoals)
{
if (!g.Enabled)
{
continue;
}
ArithExpr gr = mkGoalRow(g.Index);
if (g.Minimize)
{
_goals.Add(g, _optSolver.MkMinimize(gr));
}
else
{
_goals.Add(g, _optSolver.MkMaximize(gr));
}
}
if (_goals.Any() && parameters.SMT2LogFile != null)
{
Debug.WriteLine("Dumping SMT2 benchmark to log file...");
File.WriteAllText(parameters.SMT2LogFile, _optSolver.ToString());
}
bool aborted = parameters.QueryAbort();
if (!aborted)
{
// Start the abort thread
AbortWorker abortWorker = new AbortWorker(_context, parameters.QueryAbort);
Thread abortThread = new Thread(abortWorker.Start);
abortThread.Start();
// Now solve the problem
Status status = _optSolver.Check();
// Stop the abort thread
abortWorker.Stop();
abortThread.Join();
switch (status)
{
case Status.SATISFIABLE:
Microsoft.Z3.Model model = _optSolver.Model;
Debug.Assert(model != null, "Should be able to get Z3 model.");
// Remember the solution values
foreach (KeyValuePair <int, Expr> pair in _variables)
{
var value = Utils.ToRational(model.Eval(pair.Value, true));
_model.SetValue(pair.Key, value);
}
// Remember all objective values
foreach (var pair in _goals)
{
var optimalValue = Utils.ToRational(pair.Value.Upper);
_model.SetValue(pair.Key.Index, optimalValue);
}
model.Dispose();
setResult(_goals.Any() ? Z3Result.Optimal : Z3Result.Feasible);
break;
case Status.UNSATISFIABLE:
setResult(Z3Result.Infeasible);
break;
case Status.UNKNOWN:
if (abortWorker.Aborted)
{
Microsoft.Z3.Model subOptimalModel = _optSolver.Model;
if (subOptimalModel != null && subOptimalModel.NumConsts != 0)
{
// Remember the solution values
foreach (KeyValuePair <int, Expr> pair in _variables)
{
var value = Utils.ToRational(subOptimalModel.Eval(pair.Value, true));
_model.SetValue(pair.Key, value);
}
// Remember all objective values
foreach (var pair in _goals)
{
var optimalValue = Utils.ToRational(pair.Value.Upper);
_model.SetValue(pair.Key.Index, optimalValue);
}
subOptimalModel.Dispose();
setResult(Z3Result.LocalOptimal);
}
else
{
setResult(Z3Result.Infeasible);
}
}
else
{
setResult(Z3Result.Interrupted);
}
break;
default:
Debug.Assert(false, "Unrecognized Z3 Status");
break;
}
}
}
finally
{
_isSolving = false;
}
// Now kill Z3
DestructSolver(true);
}
