public void UpdateUnsatCore(ProverInterface proverInterface, Dictionary<Variable, bool> assignment)
{
DateTime now = DateTime.UtcNow;
Boogie2VCExprTranslator exprTranslator = proverInterface.Context.BoogieExprTranslator;
proverInterface.Push();
proverInterface.Assert(conjecture, false);
foreach (var v in assignment.Keys) {
if (assignment[v]) continue;
proverInterface.Assert(exprTranslator.LookupVariable(v), false);
}
List<Variable> assumptionVars = new List<Variable>();
List<VCExpr> assumptionExprs = new List<VCExpr>();
foreach (var v in assignment.Keys) {
if (!assignment[v]) continue;
assumptionVars.Add(v);
assumptionExprs.Add(exprTranslator.LookupVariable(v));
}
List<int> unsatCore;
ProverInterface.Outcome tmp = proverInterface.CheckAssumptions(assumptionExprs, out unsatCore, handler);
System.Diagnostics.Debug.Assert(tmp == ProverInterface.Outcome.Valid);
unsatCoreSet = new HashSet<Variable>();
foreach (int i in unsatCore)
unsatCoreSet.Add(assumptionVars[i]);
proverInterface.Pop();
double unsatCoreQueryTime = (DateTime.UtcNow - now).TotalSeconds;
stats.unsatCoreProverTime += unsatCoreQueryTime;
stats.numUnsatCoreProverQueries++;
}
// MAXSAT
public void Explain(ProverInterface proverInterface,
Dictionary<Variable, bool> assignment, Variable refutedConstant)
{
Contract.Assert(CommandLineOptions.Clo.ExplainHoudini);
collector.examples.Clear();
// debugging
houdiniAssertConstants.Iter(v => System.Diagnostics.Debug.Assert(assignment.ContainsKey(v)));
houdiniAssumeConstants.Iter(v => System.Diagnostics.Debug.Assert(assignment.ContainsKey(v)));
Contract.Assert(assignment.ContainsKey(refutedConstant));
Contract.Assert(houdiniAssertConstants.Contains(refutedConstant));
var hardAssumptions = new List<VCExpr>();
var softAssumptions = new List<VCExpr>();
Boogie2VCExprTranslator exprTranslator = proverInterface.Context.BoogieExprTranslator;
VCExpressionGenerator exprGen = proverInterface.VCExprGen;
var controlExpr = VCExpressionGenerator.True;
foreach (var tup in assignment)
{
Variable constant = tup.Key;
VCExprVar exprVar = exprTranslator.LookupVariable(constant);
var val = tup.Value;
if (houdiniAssumeConstants.Contains(constant))
{
if (tup.Value)
hardAssumptions.Add(exprVar);
else
// Previously removed assumed candidates are the soft constraints
softAssumptions.Add(exprVar);
}
else if (houdiniAssertConstants.Contains(constant))
{
if (constant == refutedConstant)
hardAssumptions.Add(exprVar);
else
hardAssumptions.Add(exprGen.Not(exprVar));
}
else
{
if (tup.Value)
hardAssumptions.Add(exprVar);
else
hardAssumptions.Add(exprGen.Not(exprVar));
}
// For an asserted condition (c ==> \phi),
// ExplainHoudini's extra control constants (c_pos, c_neg) are used as follows:
// (true, true): "assert \phi"
// (false, _): "assert false"
// (true, false): "assert true"
if (constant != refutedConstant && constantToControl.ContainsKey(constant.Name))
{
var posControl = constantToControl[constant.Name].Item1;
var negControl = constantToControl[constant.Name].Item2;
// Handle self-recursion
if (houdiniAssertConstants.Contains(constant) && houdiniAssumeConstants.Contains(constant))
{
// disable this assert
controlExpr = exprGen.And(controlExpr, exprGen.And(exprTranslator.LookupVariable(posControl), exprGen.Not(exprTranslator.LookupVariable(negControl))));
}
else
{
// default values for control variables
controlExpr = exprGen.And(controlExpr, exprGen.And(exprTranslator.LookupVariable(posControl), exprTranslator.LookupVariable(negControl)));
}
}
}
hardAssumptions.Add(exprGen.Not(conjecture));
// default values for control variables
Contract.Assert(constantToControl.ContainsKey(refutedConstant.Name));
var pc = constantToControl[refutedConstant.Name].Item1;
var nc = constantToControl[refutedConstant.Name].Item2;
var controlExprNoop = exprGen.And(controlExpr,
exprGen.And(exprTranslator.LookupVariable(pc), exprTranslator.LookupVariable(nc)));
var controlExprFalse = exprGen.And(controlExpr,
exprGen.And(exprGen.Not(exprTranslator.LookupVariable(pc)), exprGen.Not(exprTranslator.LookupVariable(nc))));
if (CommandLineOptions.Clo.Trace)
{
Console.WriteLine("Verifying (MaxSat) " + descriptiveName);
}
DateTime now = DateTime.UtcNow;
var el = CommandLineOptions.Clo.ProverCCLimit;
CommandLineOptions.Clo.ProverCCLimit = 1;
var outcome = ProverInterface.Outcome.Undetermined;
do
{
List<int> unsatisfiedSoftAssumptions;
hardAssumptions.Add(controlExprNoop);
outcome = proverInterface.CheckAssumptions(hardAssumptions, softAssumptions, out unsatisfiedSoftAssumptions, handler);
hardAssumptions.RemoveAt(hardAssumptions.Count - 1);
if (outcome == ProverInterface.Outcome.TimeOut || outcome == ProverInterface.Outcome.OutOfMemory || outcome == ProverInterface.Outcome.Undetermined)
break;
var reason = new HashSet<string>();
unsatisfiedSoftAssumptions.Iter(i => reason.Add(softAssumptions[i].ToString()));
if (CommandLineOptions.Clo.Trace)
{
Console.Write("Reason for removal of {0}: ", refutedConstant.Name);
reason.Iter(r => Console.Write("{0} ", r));
Console.WriteLine();
}
// Get rid of those constants from the "reason" that can even make
// "assert false" pass
hardAssumptions.Add(controlExprFalse);
var softAssumptions2 = new List<VCExpr>();
for (int i = 0; i < softAssumptions.Count; i++)
{
if (unsatisfiedSoftAssumptions.Contains(i))
{
softAssumptions2.Add(softAssumptions[i]);
continue;
}
hardAssumptions.Add(softAssumptions[i]);
}
var unsatisfiedSoftAssumptions2 = new List<int>();
outcome = proverInterface.CheckAssumptions(hardAssumptions, softAssumptions2, out unsatisfiedSoftAssumptions2, handler);
if (outcome == ProverInterface.Outcome.TimeOut || outcome == ProverInterface.Outcome.OutOfMemory || outcome == ProverInterface.Outcome.Undetermined)
break;
unsatisfiedSoftAssumptions2.Iter(i => reason.Remove(softAssumptions2[i].ToString()));
if (CommandLineOptions.Clo.Trace)
{
Console.Write("Revised reason for removal of {0}: ", refutedConstant.Name);
reason.Iter(r => Console.Write("{0} ", r));
Console.WriteLine();
}
foreach (var r in reason)
{
Houdini.explainHoudiniDottyFile.WriteLine("{0} -> {1} [ label = \"{2}\" color=red ];", refutedConstant.Name, r, descriptiveName);
}
} while (false);
if (outcome == ProverInterface.Outcome.TimeOut || outcome == ProverInterface.Outcome.OutOfMemory || outcome == ProverInterface.Outcome.Undetermined)
{
Houdini.explainHoudiniDottyFile.WriteLine("{0} -> {1} [ label = \"{2}\" color=red ];", refutedConstant.Name, "TimeOut", descriptiveName);
}
CommandLineOptions.Clo.ProverCCLimit = el;
double queryTime = (DateTime.UtcNow - now).TotalSeconds;
stats.proverTime += queryTime;
stats.numProverQueries++;
if (CommandLineOptions.Clo.Trace)
{
Console.WriteLine("Time taken = " + queryTime);
}
}