/// <summary>
/// Returns a new table that is the union of the input tables.
/// </summary>
/// <param name="parameters">The model's parameters</param>
/// <param name="first">First table</param>
/// <param name="second">Second table</param>
/// <param name="newState">Function to calculate state of merged value combinations</param>
/// <returns>The new table</returns>
public static ParameterInteraction Merge <T>(IList <ParameterBase> parameters, ParameterInteraction first, ParameterInteraction second, Func <ValueCombinationState, ValueCombinationState, ValueCombinationState> newState)
where T : new()
{
List <int> parameterIndices = first.Parameters.Union(second.Parameters).ToList();
parameterIndices.Sort();
var mergedInteraction = new ParameterInteraction(parameterIndices);
var valueTable = ParameterInteractionTable <T> .GenerateValueTable(parameters, mergedInteraction);
foreach (var value in valueTable)
{
mergedInteraction.Combinations.Add(new ValueCombination(value, mergedInteraction));
}
foreach (var combination in mergedInteraction.Combinations)
{
var firstMatch = first.Combinations.First((c) => ParameterInteractionTable <T> .MatchCombination(c, combination));
var secondMatch = second.Combinations.First((c) => ParameterInteractionTable <T> .MatchCombination(c, combination));
combination.State = newState(firstMatch.State, secondMatch.State);
}
return(mergedInteraction);
}
// helper to implement Constraint.SatisfiesConstraint
internal static ConstraintSatisfaction SatisfiesContraint <T>(Model <T> model, ValueCombination combination, ParameterInteraction interaction) where T : new()
{
Debug.Assert(model != null && combination != null && interaction != null);
var parameterMap = combination.ParameterToValueMap;
for (int i = 0; i < interaction.Parameters.Count; i++)
{
if (!parameterMap.ContainsKey(interaction.Parameters[i]))
{
return(ConstraintSatisfaction.InsufficientData);
}
}
for (int i = 0; i < interaction.Combinations.Count; i++)
{
if (ParameterInteractionTable <T> .MatchCombination(interaction.Combinations[i], combination))
{
if (interaction.Combinations[i].State == ValueCombinationState.Excluded)
{
return(ConstraintSatisfaction.Unsatisfied);
}
}
}
return(ConstraintSatisfaction.Satisfied);
}
// helper to implement Constraint.SatisfiesConstraint
internal static ConstraintSatisfaction SatisfiesContraint(Model model, ValueCombination combination, ParameterInteraction interaction)
{
Debug.Assert(model != null && combination != null && interaction != null);
if (!interaction.Parameters.All((i) => combination.ParameterToVaueMap.ContainsKey(i)))
{
return(ConstraintSatisfaction.InsufficientData);
}
var matches = interaction.Combinations.Where((c) => ParameterInteractionTable.MatchCombination(c, combination));
if (matches.Any((c) => c.State == ValueCombinationState.Excluded))
{
return(ConstraintSatisfaction.Unsatisfied);
}
return(ConstraintSatisfaction.Satisfied);
}
private void GenerateHigherOrderDependentExclusions(Model <T> model, int order, List <int> parameterInteractionCounts, ParameterInteraction completeInteraction, IEnumerable <ValueCombination> allowedCombinations)
{
// generate the combinations for orders between order and completerInteraction.Parameters.Count
foreach (var count in parameterInteractionCounts)
{
IList <int[]> parameterCombinations = GenerateCombinations(completeInteraction.Parameters.Count, count);
foreach (var combinations in parameterCombinations)
{
var interaction = new ParameterInteraction(combinations.Select((i) => completeInteraction.Parameters[i]));
var possibleValues = ParameterInteractionTable <T> .GenerateValueTable(model.Parameters, interaction);
foreach (var value in possibleValues)
{
interaction.Combinations
.Add(new ValueCombination(value, interaction)
{
State = ValueCombinationState.Covered
});
}
// find combinations that should be excluded
var excludedCombinations = new List <ValueCombination>();
foreach (var combination in interaction.Combinations)
{
if (!combination.ParameterToValueMap.Any((p) => !completeInteraction.Parameters.Contains(p.Key)) &&
!allowedCombinations.Any((c) => MatchCombination(combination, c)))
{
excludedCombinations.Add(combination);
}
}
if (excludedCombinations.Count() > 0)
{
foreach (var combination in excludedCombinations)
{
combination.State = ValueCombinationState.Excluded;
}
MergeConstraintInteraction(order, interaction);
}
}
}
}
// helper to implement Constraint.GetExcludeCombinations
internal static ParameterInteraction GetExcludedCombinations <T>(Model model, Constraint constraint, Parameter first, Parameter second, T value, Func <T, T, bool> comparison)
{
Debug.Assert(first != null && model != null && constraint != null && comparison != null);
List <int> parameterIndices = new List <int>();
parameterIndices.Add(model.Parameters.IndexOf(first));
if (second != null)
{
parameterIndices.Add(model.Parameters.IndexOf(second));
}
parameterIndices.Sort();
ParameterInteraction interaction = new ParameterInteraction(parameterIndices);
List <int[]> valueTable = ParameterInteractionTable.GenerateValueTable(model.Parameters, interaction);
foreach (var valueIndices in valueTable)
{
T value1, value2;
value1 = (T)first[valueIndices[0]];
if (second == null)
{
value2 = value;
}
else
{
value2 = (T)second[valueIndices[1]];
}
ValueCombinationState comboState = comparison(value1, value2) ? ValueCombinationState.Covered : ValueCombinationState.Excluded;
interaction.Combinations.Add(new ValueCombination(valueIndices, interaction)
{
State = comboState
});
}
return(interaction);
}
// for the following system:
// if A == 0 then B == 0
// if B == 0 then C == 0
// if C == 0 then A == 1
// all combinations with A == 0 need to be excluded, but this is impossible to determine when looking at individual constraints
// to do this:
// - create groups of constraints where all members have a parameter that overlaps with another constraint
// - create ParameterInteraction for each group of constraints
// - for the existing uncovered combinations, if they excluded in every matching combination in the group interaction, mark excluded
// - higher order combinations that match the order of a constraint's interaction can also need to be exculded
private void GenerateDependentConstraintInteractions(Model model, int order, List <ParameterInteraction> constraintInteractions)
{
// group all the constraint parameter interactions that share parameters
var dependentConstraintSets = new List <List <ParameterInteraction> >();
while (constraintInteractions.Count > 0)
{
var dependentConstraintSet = new List <ParameterInteraction>();
var interactionsToExplore = new List <ParameterInteraction>();
interactionsToExplore.Add(constraintInteractions[0]);
constraintInteractions.RemoveAt(0);
while (interactionsToExplore.Count > 0)
{
ParameterInteraction current = interactionsToExplore[0];
interactionsToExplore.RemoveAt(0);
dependentConstraintSet.Add(current);
var dependentInteractions =
(from constraint in constraintInteractions
where constraint.Parameters.Any((i) => current.Parameters.Contains(i))
select constraint).ToList();
foreach (var dependentInteraction in dependentInteractions)
{
constraintInteractions.Remove(dependentInteraction);
}
interactionsToExplore.AddRange(dependentInteractions);
}
dependentConstraintSets.Add(dependentConstraintSet);
}
// walk over the groups of constraints
foreach (var dependentConstraintSet in dependentConstraintSets)
{
// if there's only one constraint no more processing is necessary
if (dependentConstraintSet.Count <= 1)
{
continue;
}
// merge the interactions of all the constraints
var uniqueParameters = new Dictionary <int, bool>();
var parameterInteractionCounts = new List <int>();
for (int i = 0; i < dependentConstraintSet.Count; i++)
{
foreach (var parameter in dependentConstraintSet[i].Parameters)
{
uniqueParameters[parameter] = true;
}
if (dependentConstraintSet[i].Parameters.Count > order)
{
parameterInteractionCounts.Add(dependentConstraintSet[i].Parameters.Count);
}
}
var sortedParameters = uniqueParameters.Keys.ToList();
sortedParameters.Sort();
ParameterInteraction completeInteraction = new ParameterInteraction(sortedParameters);
var valueTable = ParameterInteractionTable.GenerateValueTable(model.Parameters, completeInteraction);
foreach (var value in valueTable)
{
completeInteraction.Combinations
.Add(new ValueCombination(value, completeInteraction)
{
State = ValueCombinationState.Covered
});
}
// calculate the excluded combinations in the new uber interaction
var completeInteractionExcludedCombinations = new List <ValueCombination>();
// find the combinations from the uber interaction that aren't excluded
// if a combination is a subset of any of these it is not excluded
var allowedCombinations = new List <ValueCombination>();
foreach (var combination in completeInteraction.Combinations)
{
bool exclude = false;
foreach (var constraint in completeConstraints)
{
if (constraint.SatisfiesContraint(model, combination) == ConstraintSatisfaction.Unsatisfied)
{
exclude = true;
break;
}
}
if (exclude)
{
combination.State = ValueCombinationState.Excluded;
completeInteractionExcludedCombinations.Add(combination);
}
else
{
allowedCombinations.Add(combination);
}
}
// find the existing combinations that are never allowed in the uber interaction
var individualInteractionExcludedCombinations =
from interaction in Interactions
from combination in interaction.Combinations
where !combination.ParameterToValueMap.Any((p) => !completeInteraction.Parameters.Contains(p.Key)) &&
!allowedCombinations.Any((c) => MatchCombination(combination, c))
select combination;
// mark the combinations in the table as excluded
foreach (var combination in individualInteractionExcludedCombinations)
{
combination.State = ValueCombinationState.Excluded;
}
GenerateHigherOrderDependentExclusions(model, order, parameterInteractionCounts, completeInteraction, allowedCombinations);
}
}
// this is the actual generation function
// returns a list of indices that allow lookup of the actual value in the model
private static IList <VariationIndexTagPair> GenerateVariationIndices <T>(ParameterInteractionTable <T> interactions, int variationSize, int seed, long maxVariations, object defaultTag) where T : new()
{
Random random = new Random(seed);
List <VariationIndexTagPair> variations = new List <VariationIndexTagPair>();
// while there a uncovered values
while (!interactions.IsCovered())
{
int[] candidate = new int[variationSize];
object variationTag = defaultTag;
// this is a scatch variable so new arrays won't be allocated for every candidate
int[] proposedCandidate = new int[variationSize];
for (int i = 0; i < candidate.Length; i++)
{
// -1 indicates an empty slot
candidate[i] = -1;
}
IEnumerable <ParameterInteraction> candidateInteractions = interactions.Interactions;
// while there are empty slots
while (candidate.Any((i) => i == -1))
{
// if all the slots are empty
if (candidate.All((i) => i == -1))
{
// then pick the first uncovered combination from the most uncovered parameter interaction
int mostUncovered =
interactions.Interactions.Max((i) => i.GetUncoveredCombinationsCount());
var interaction = interactions.Interactions.First((i) => i.GetUncoveredCombinationsCount() == mostUncovered);
var combination = interaction.Combinations.First((c) => c.State == ValueCombinationState.Uncovered);
foreach (var valuePair in combination.ParameterToValueMap)
{
candidate[valuePair.Key] = valuePair.Value;
}
variationTag = combination.Tag == null || combination.Tag == defaultTag ? variationTag : combination.Tag;
combination.State = ValueCombinationState.Covered;
}
else
{
// find interactions that aren't covered by the current candidate variation
var incompletelyCoveredInteractions =
from interaction in candidateInteractions
where interaction.Parameters.Any((i) => candidate[i] == -1)
select interaction;
candidateInteractions = incompletelyCoveredInteractions;
// find values that can be added to the current candidate
var compatibleValues = new List <ValueCombination>();
foreach (var interaction in incompletelyCoveredInteractions)
{
foreach (var combination in interaction.Combinations)
{
if (IsCompatibleValue(combination, candidate))
{
compatibleValues.Add(combination);
}
}
}
// get the uncovered values
var uncoveredValues = compatibleValues.Where((v) => v.State == ValueCombinationState.Uncovered).ToList();
// calculate what the candidate will look like if add an uncovered value
var proposedCandidates = new List <CandidateCoverage>();
foreach (var uncoveredValue in uncoveredValues)
{
CreateProposedCandidate(uncoveredValue, candidate, proposedCandidate);
if (!IsExcluded(interactions.ExcludedCombinations, proposedCandidate))
{
var coverage = new CandidateCoverage
{
Value = uncoveredValue,
CoverageCount = uncoveredValues.Count((v) => IsCovered(v, proposedCandidate)),
};
proposedCandidates.Add(coverage);
}
}
// if any of the proposed candidates isn't exclude
if (proposedCandidates.Count > 0)
{
// find the value that will cover the most combinations
int maxCovered = proposedCandidates.Max((c) => c.CoverageCount);
double maxWeight = proposedCandidates.Where((c) => c.CoverageCount == maxCovered).Max((c) => c.Value.Weight);
ValueCombination proposedValue = proposedCandidates.First((c) => c.CoverageCount == maxCovered && c.Value.Weight == maxWeight).Value;
// add this value to candidate and mark all values as such
foreach (var valuePair in proposedValue.ParameterToValueMap)
{
candidate[valuePair.Key] = valuePair.Value;
}
variationTag = proposedValue.Tag == null || proposedValue.Tag == defaultTag ? variationTag : proposedValue.Tag;
// get the newly covered values so they can be marked
var newlyCoveredValue = uncoveredValues.Where((v) => IsCovered(v, candidate)).ToList();
foreach (var value in newlyCoveredValue)
{
value.State = ValueCombinationState.Covered;
}
}
else
{
// no uncovered values can be added with violating a constraint, add a random covered value
var compatibleWeightBuckets = compatibleValues.GroupBy((v) => v.Weight).OrderByDescending((v) => v.Key);
ValueCombination value = null;
bool combinationFound = false;
foreach (var bucket in compatibleWeightBuckets)
{
int count = bucket.Count();
int attempts = 0;
do
{
value = bucket.ElementAt(random.Next(count - 1));
CreateProposedCandidate(value, candidate, proposedCandidate);
if (!interactions.ExcludedCombinations.Any((c) => IsCovered(c, proposedCandidate)))
{
combinationFound = true;
}
attempts++;
// this is a heuristic, since we're pulling random values just going to count probably
// means we've attempted duplicates, going to 2 * count means we've probably tried
// everything at least once
if (attempts > count * 2)
{
break;
}
}while (!combinationFound);
if (combinationFound)
{
break;
}
}
if (!combinationFound)
{
throw new InternalVariationGenerationException("Unable to find candidate with no exclusions.");
}
// add this value to candidate and mark all values as such
foreach (var valuePair in value.ParameterToValueMap)
{
candidate[valuePair.Key] = valuePair.Value;
}
variationTag = value.Tag == null || value.Tag == defaultTag ? variationTag : value.Tag;
}
}
}
variations.Add(new VariationIndexTagPair {
Indices = candidate, Tag = variationTag
});
// more variations than are need to exhaustively test the model have been adde
if (variations.Count > maxVariations)
{
throw new InternalVariationGenerationException("More variations than an exhaustive suite produced.");
}
}
return(variations);
}
// this is the actual generation function
// returns a list of indices that allow lookup of the actual value in the model
private static IList <int[]> GenerateVariationIndices(ParameterInteractionTable interactions, int variationSize, int seed, int maxVariations)
{
Random random = new Random(seed);
List <int[]> variations = new List <int[]>();
// while there a uncovered values
while (!interactions.IsCovered())
{
int[] candidate = new int[variationSize];
for (int i = 0; i < candidate.Length; i++)
{
// -1 indicates an empty slot
candidate[i] = -1;
}
// while there are empty slots
while (candidate.Any((i) => i == -1))
{
// if all the slots are empty
if (candidate.All((i) => i == -1))
{
// then pick the first uncovered combination from the most uncovered parameter interaction
int mostUncovered =
interactions.Interactions.Max((i) => i.GetUncoveredCombinationsCount());
var interaction = interactions.Interactions.First((i) => i.GetUncoveredCombinationsCount() == mostUncovered);
var combination = interaction.Combinations.First((c) => c.State == ValueCombinationState.Uncovered);
foreach (var valuePair in combination.ParameterToVaueMap)
{
candidate[valuePair.Key] = valuePair.Value;
}
combination.State = ValueCombinationState.Covered;
}
else
{
// find interactions that aren't covered by the current candidate variation
var incompletelyCoveredInteractions =
from interaction in interactions.Interactions
where interaction.Parameters.Any((i) => candidate[i] == -1)
select interaction;
// find values that can be added to the current candidate
var compatibleValues =
from interaction in incompletelyCoveredInteractions
from combination in interaction.Combinations
where IsCompatibleValue(combination, candidate)
select combination;
// get the uncovered values
var uncoveredValues = compatibleValues.Where((v) => v.State == ValueCombinationState.Uncovered).ToList();
// calculate what the candidate will look like if add an uncovered value
var proposedCandidates =
from value in uncoveredValues
select new
{
Value = value,
Candidate = CreateProposedCandidate(value, candidate)
};
// if any of the proposed candidates isn't exclude
if (proposedCandidates.Any((a) => !IsExcluded(interactions.ExcludedCombinations(), a.Candidate)))
{
// find the value that will cover the most combinations
int maxCovered = proposedCandidates.Max(
(a) => uncoveredValues.Count(
(v) => IsCovered(v, a.Candidate) &&
!IsExcluded(interactions.ExcludedCombinations(), a.Candidate)));
ValueCombination proposedValue = proposedCandidates.First(
(a) => uncoveredValues.Count(
(v) => IsCovered(v, a.Candidate) &&
!IsExcluded(interactions.ExcludedCombinations(), a.Candidate)) == maxCovered).Value;
// add this value to candidate and mark all values as such
foreach (var valuePair in proposedValue.ParameterToVaueMap)
{
candidate[valuePair.Key] = valuePair.Value;
}
// get the newly covered values so they can be marked
var newlyCoveredValue = uncoveredValues.Where((v) => IsCovered(v, candidate)).ToList();
foreach (var value in newlyCoveredValue)
{
value.State = ValueCombinationState.Covered;
}
}
else
{
// no uncovered values can be added with violating a constraint, add a random covered value
int count = compatibleValues.Count();
int attempts = 0;
ValueCombination value;
int[] proposedCandidate;
do
{
value = compatibleValues.ElementAt(random.Next(count - 1));
proposedCandidate = CreateProposedCandidate(value, candidate);
// this is a heuristic, since we're pulling random values just going to count probably
// means we've attempted duplicates, going to 2 * count means we've probably tried
// everything at least once
if (attempts > count * 2)
{
throw new InternalVariationGenerationException("Unable to find candidate with no exclusions.");
}
attempts++;
}while (interactions.ExcludedCombinations().Any((c) => IsCovered(c, CreateProposedCandidate(value, candidate))));
// add this value to candidate and mark all values as such
foreach (var valuePair in value.ParameterToVaueMap)
{
candidate[valuePair.Key] = valuePair.Value;
}
}
}
}
variations.Add(candidate);
// more variations than are need to exhaustively test the model have been adde
if (variations.Count > maxVariations)
{
throw new InternalVariationGenerationException("More variations than an exhaustive suite produced.");
}
}
return(variations);
}
