/// <summary>
/// Produces a witness body given input restrictions, output
/// restrictions and a transform.
/// </summary>
/// <param name="inputBodyRestriction"></param>
/// <param name="bodyTransform"></param>
/// <param name="outputBodyRestriction"></param>
/// <returns></returns>
public static Z3Body GenerateWitness(
CompositeBodyRestriction inputBodyRestriction,
BodyTransform bodyTransform,
CompositeBodyRestriction outputBodyRestriction)
{
var body = Z3Body.MkZ3Const();
var transformedBody = bodyTransform.Transform(body);
var expr1 = inputBodyRestriction.Evaluate(body);
var expr2 = outputBodyRestriction.Evaluate(transformedBody);
var expr = Z3.Context.MkAnd(expr1, expr2);
var evaluatedJoints =
JointTypeHelper.MergeJointTypeLists(
inputBodyRestriction.GetJointTypes(),
bodyTransform.GetJointTypes(),
outputBodyRestriction.GetJointTypes());
var checkResult = CheckStatus(expr);
if (checkResult.Status == Status.SATISFIABLE)
{
var witness = CreateBodyWitness(
body,
checkResult.Model,
evaluatedJoints,
JointTypeHelper.CreateDefaultZ3Body());
return(witness);
}
else
{
return(null);
}
}
/// <summary>
/// Generates a witness body tha matches the restrictions that
/// are passed in.
/// </summary>
/// <param name="bodyRestriction"></param>
/// <returns></returns>
public static Z3Body GenerateWitness(IBodyRestriction bodyRestriction)
{
var body = Z3Body.MkZ3Const();
var expr = bodyRestriction.Evaluate(body);
var checkResult = CheckStatus(expr);
var witness = CreateBodyWitness(
body,
checkResult.Model,
bodyRestriction.GetJointTypes(),
JointTypeHelper.CreateDefaultZ3Body());
return(witness);
}
/// <summary>
/// Checks if the pose is within default safety
/// restrictions when the transform and restrictions
/// are applied.
/// </summary>
/// <returns>True if it's safe</returns>
public static bool IsWithinSafetyRestrictions(Pose pose, out Z3Body witness)
{
Z3Body input = Z3Body.MkZ3Const();
Z3Body transformed = pose.Transform.Transform(input);
IBodyRestriction safe = Safety.DefaultSafetyRestriction();
BoolExpr inputSafe = safe.Evaluate(input);
BoolExpr transformedRestricted = pose.Restriction.Evaluate(transformed);
// Try to generate a unsafe witness using the transform
BoolExpr outputUnsafe = Z3.Context.MkNot(safe.Evaluate(transformed));
// Put together all expressions and search for unsat
BoolExpr expr = Z3.Context.MkAnd(inputSafe, transformedRestricted, outputUnsafe);
SolverCheckResult solverResult = Z3AnalysisInterface.CheckStatus(expr);
if (solverResult.Status == Status.SATISFIABLE)
{
//Z3Body
witness =
Z3AnalysisInterface.CreateBodyWitness(
transformed,
solverResult.Model,
pose.GetAllJointTypes(),
JointTypeHelper.CreateDefaultZ3Body());
return(false);
}
else if (solverResult.Status == Status.UNKNOWN)
{
//Z3Body
witness = JointTypeHelper.CreateDefaultZ3Body();
return(false);
}
else
{
Contract.Assert(solverResult.Status == Status.UNSATISFIABLE);
witness = null;
return(true);
}
}
/// <summary>
/// Check for pairwise ambiguity
/// </summary>
/// <returns></returns>
public static bool HasPairwiseConflicts(App app, out List <PairwiseConflictException> allExceptions, out List <AmbiguityTime> ambiguityTimes, int precision = 15)
{
List <Gesture> conflictGestures = (List <Gesture>)app.Gestures;
bool result = false;
allExceptions = new List <PairwiseConflictException>();
ambiguityTimes = new List <AmbiguityTime>();
for (int i = 0; i < conflictGestures.Count - 1; i++)
{
for (int j = i + 1; j < conflictGestures.Count; j++)
{
var gesture1 = conflictGestures[i];
var gesture2 = conflictGestures[j];
// Create const input body
var input = Z3Body.MkZ3Const();
var allJoints = EnumUtil.GetValues <JointType>().ToList();
Z3Body transformed1 = null;
Z3Body transformed2 = null;
BoolExpr evaluation1 = Z3Math.True;
BoolExpr evaluation2 = Z3Math.True;
// Pass input through both gestures
gesture1.FinalResult(input, out transformed1, out evaluation1);
gesture2.FinalResult(input, out transformed2, out evaluation2);
// Check if it is possible that both outputs are equals
// This is performed by checking if is possible that all expressions are true
var isNearExpr = transformed1.IsNearerThan(
transformed2, precision);
var expr = Z3.Context.MkAnd(isNearExpr, evaluation1, evaluation2);
// If we are dumping Z3 constraints, then convert the expression to a SMTLIB formatted string
// and dump it to disk. Note this is not included in the timing for the individual pair of gestures,
// but it _is_ included in the timing for the app overall.
if (DumpZ3Constraints)
{
string exprName = String.Join("X", gesture1.Name, gesture2.Name);
string exprPath = exprName + ".smt2";
Z3AnalysisInterface.WriteExprToDisk(expr, exprName, exprPath);
}
// Check if we have an ambiguity conflict. Record the time it takes.
var stopwatch = new Stopwatch();
stopwatch.Start();
var checkResult = Z3AnalysisInterface.CheckStatus(expr);
stopwatch.Stop();
if (checkResult.Status == Status.SATISFIABLE)
{
var witness = Z3AnalysisInterface.CreateBodyWitness(
input,
checkResult.Model,
allJoints,
JointTypeHelper.CreateDefaultZ3Body());
var exception = new PairwiseConflictException(
"Conflict detected between pair of gestures",
gesture1,
gesture2,
witness);
allExceptions.Add(exception);
result = true;
}
// TODO the witness here should exist, this case shouldn't be needed
else if (checkResult.Status == Status.UNKNOWN)
{
var witness = JointTypeHelper.CreateDefaultZ3Body();
var exception = new PairwiseConflictException(
"Conflict detected between pair of gestures, the reason is unknown",
gesture1,
gesture2,
witness);
allExceptions.Add(exception);
result = true;
}
ambiguityTimes.Add(new AmbiguityTime
{
Gesture1 = gesture1,
Gesture2 = gesture2,
Time = stopwatch.ElapsedMilliseconds,
Conflict = result,
CheckResult = checkResult
});
}
}
return(result);
}
