/// <summary>
/// Stores information about state pairs and its transitions.
/// Used by HSI method to generate harmonized sets.
/// </summary>
/// <summary>
/// Apply fsm inputs and set points from a state-pair to another one.
/// </summary>
public List <FailnessRecord> GetFailnessTable()
{
//if (this.failnessTable != null)
// return this.failnessTable;
this.failnessTable = new List <FailnessRecord>();
StatePair[] pairs = this.GetStatePairGroup();
for (int i = 0; i < pairs.Length; i++)
{
StatePair pair = pairs[i];
for (int j = 0; j < this.fsm.InputAlphabet.Count; j++)
{
FailnessRecord record = new FailnessRecord();
record.SourcePair = pair;
record.Input = this.fsm.InputAlphabet[j];
String outputA = String.Empty, outputB = String.Empty;
State targetA = null, targetB = null;
//gets record target
foreach (Transition t in this.fsm.Transitions.Where(x => x.Input == record.Input))
{
if (t.SourceState == pair.StateA)
{
targetA = t.TargetState;
outputA = t.Output;
}
else if (t.SourceState == pair.StateB)
{
targetB = t.TargetState;
outputB = t.Output;
}
}
if (targetA == null || targetB == null)
{
record.Status = Failness.Invalid;
}
else if (outputA != outputB)
{
record.Status = Failness.Fail;
}
else
{
record.Status = Failness.Valid;
}
record.TargetPair = pairs.Where(x => (x.StateA == targetA && x.StateB == targetB) || (x.StateB == targetA && x.StateA == targetB)).FirstOrDefault();
this.failnessTable.Add(record);
}
}
return(failnessTable);
}
/// <summary>
/// Returns input which made state pair failed. If current
/// State pair is not fail, locate the shortest sequence to
/// reach a failed state pair.
/// </summary>
private String[] FindShortestInputToFail(List <FailnessRecord> failnessTable, StatePair[] statePairGroup, StatePair sp)
{
IEnumerable <FailnessRecord> foundRecords = from FailnessRecord f in failnessTable
where f.SourcePair.Equals(sp) && f.Status == Failness.Fail
select f;
//it is fail. get input which made it fail
if (foundRecords.Count() > 0)
{
FailnessRecord record = foundRecords.First(); //will never be null
return(new String[] { record.Input });
}
else //is invalid or valid
{
//make a new query, so we can proceed on the valid way
foundRecords = from FailnessRecord f in failnessTable
where f.SourcePair.Equals(sp) && f.Status == Failness.Valid
select f;
//find available sequences to fail
List <String[]> foundSequences = new List <String[]>();
foreach (FailnessRecord f in foundRecords)
{
String[] sequence = FindShortestInputToFail(failnessTable, statePairGroup, f.TargetPair);
if (sequence != null)
{
List <String> newSequence = new List <String>();
newSequence.Add(f.Input);
newSequence.AddRange(sequence);
foundSequences.Add(newSequence.ToArray());
}
}
//return the shortest sequence
String[] bestFit = null;
foreach (String[] sequence in foundSequences)
{
if (sequence.Length < 2)
{
continue;
}
if (bestFit == null || bestFit.Length > sequence.Length)
{
bestFit = sequence;
}
}
return(bestFit);
}
}
