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.OutOfResource || 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.OutOfResource || outcome == ProverInterface.Outcome.Undetermined) { break; } unsatisfiedSoftAssumptions2.Iter(i => reason.Remove(softAssumptions2[i].ToString())); var reason1 = new HashSet <string>(); //these are the reasons for inconsistency unsatisfiedSoftAssumptions2.Iter(i => reason1.Add(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); } //also add the removed reasons using dotted edges (requires- x != 0, requires- x == 0 ==> assert x != 0) foreach (var r in reason1) { Houdini.explainHoudiniDottyFile.WriteLine("{0} -> {1} [ label = \"{2}\" color=blue style=dotted ];", refutedConstant.Name, r, descriptiveName); } } while (false); if (outcome == ProverInterface.Outcome.TimeOut || outcome == ProverInterface.Outcome.OutOfMemory || outcome == ProverInterface.Outcome.OutOfResource || 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); } }