private bool SelectNextValuesForCurrentDimensionCombination(DimensionValueIndexCombination currentCombination,
ReadOnlyCollection <int> currentDimensionsToCover)
{
int currentIndex = currentDimensionsToCover.Count - 1;
bool selectNext = true;
// Continue enumerating pairwise indices until a value is selected (!selectNext)
// or we exhaust all possibilities for the current pairwise combination
// (selectNext) && (currentIndex == -1)
while ((selectNext) && (currentIndex >= 0))
{
Debug.Assert(currentCombination[currentDimensionsToCover[currentIndex]] < currentCombination.GetDimensionSize(currentDimensionsToCover[currentIndex]));
if (currentCombination[currentDimensionsToCover[currentIndex]] == currentCombination.GetDimensionSize(currentDimensionsToCover[currentIndex]) - 1)
{
currentCombination[currentDimensionsToCover[currentIndex]] = 0;
selectNext = true;
currentIndex--;
}
else
{
currentCombination[currentDimensionsToCover[currentIndex]]++;
selectNext = false;
}
}
return(!selectNext || (currentIndex != -1));
}
/// <summary>
/// Gets the allowed values for a given target dimension, given the values that have been set so far for other dimensions.
/// </summary>
/// <param name="targetDimension">The index of the target dimension (index is relative to the dimensionValues collection passed in at construction).</param>
/// <param name="setDimensionIndexes">The indexes of the dimensions where we have chosen values.</param>
/// <param name="currentCombination">The chosen values for the dimensions.</param>
/// <returns>A list of indexes refering to values from the dimensionValues collection passed in at construction that are valid according to constraints.</returns>
public ReadOnlyCollection<int> GetAllowedValueIndexesForDimension(int targetDimension, IEnumerable<int> setDimensionIndexes,
DimensionValueIndexCombination currentCombination)
{
List<int> ret = new List<int>(Enumerable.Range(0, _dimensionValues[targetDimension].Values.Count));
foreach (PossiblyExtendedConstraint constraint in _extendedConstraints.Where(c => c.IsRelevantConstraint(targetDimension, setDimensionIndexes)))
{
ret.RemoveAll(vi => !constraint.IsValid(currentCombination, targetDimension, vi));
}
return ret.AsReadOnly();
}
/// <summary>
/// Adds all the combinations of the given order as covered.
/// </summary>
/// <param name="combination">The combination to cover.</param>
/// <param name="dimensionIndexGenerator">The dimension index generator to use for getting all dimension index combinations we care about.</param>
public void AddCoveredPairwiseCombinations(DimensionValueIndexCombination combination, DimensionIndexCombinationGenerator dimensionIndexGenerator)
{
foreach (ReadOnlyCollection <int> dimensionsOfInterest in dimensionIndexGenerator.Generate())
{
if (!IsCombinationCovered(dimensionsOfInterest, combination))
{
_coveredCombinations.Add(EncodeCombination(dimensionsOfInterest, combination));
}
}
}
/// <summary>
/// Gets the allowed values for a given target dimension, given the values that have been set so far for other dimensions.
/// </summary>
/// <param name="targetDimension">The index of the target dimension (index is relative to the dimensionValues collection passed in at construction).</param>
/// <param name="setDimensionIndexes">The indexes of the dimensions where we have chosen values.</param>
/// <param name="currentCombination">The chosen values for the dimensions.</param>
/// <returns>A list of indexes refering to values from the dimensionValues collection passed in at construction that are valid according to constraints.</returns>
public ReadOnlyCollection <int> GetAllowedValueIndexesForDimension(int targetDimension, IEnumerable <int> setDimensionIndexes,
DimensionValueIndexCombination currentCombination)
{
List <int> ret = new List <int>(Enumerable.Range(0, _dimensionValues[targetDimension].Values.Count));
foreach (PossiblyExtendedConstraint constraint in _extendedConstraints.Where(c => c.IsRelevantConstraint(targetDimension, setDimensionIndexes)))
{
ret.RemoveAll(vi => !constraint.IsValid(currentCombination, targetDimension, vi));
}
return(ret.AsReadOnly());
}
/// <summary>
/// Determines whether the given combination has already been covered.
/// </summary>
/// <param name="dimensionsOfInterest">The dimensions of interest.</param>
/// <param name="combination">The combination.</param>
/// <returns>
/// <c>true</c> if the given combination is already covered; otherwise, <c>false</c>.
/// </returns>
public bool IsCombinationCovered(ICollection <int> dimensionsOfInterest, DimensionValueIndexCombination combination)
{
List <int> encodedCombination = EncodeCombination(dimensionsOfInterest, combination);
foreach (List <int> covered in _coveredCombinations)
{
if (AreEqual(covered, encodedCombination))
{
return(true);
}
}
return(false);
}
public bool IsValid(DimensionValueIndexCombination combination)
{
return IsValid(GetValueIndexes(combination));
}
public bool IsValid(DimensionValueIndexCombination combination, int targetDimensionIndex, int targetDimensionIndexValue)
{
return IsValid(GetValueIndexes(combination, targetDimensionIndex, targetDimensionIndexValue));
}
private bool SelectNextValuesForCurrentDimensionCombination(DimensionValueIndexCombination currentCombination,
ReadOnlyCollection<int> currentDimensionsToCover)
{
int currentIndex = currentDimensionsToCover.Count - 1;
bool selectNext = true;
// Continue enumerating pairwise indices until a value is selected (!selectNext)
// or we exhaust all possibilities for the current pairwise combination
// (selectNext) && (currentIndex == -1)
while ((selectNext) && (currentIndex >= 0))
{
Debug.Assert(currentCombination[currentDimensionsToCover[currentIndex]] < currentCombination.GetDimensionSize(currentDimensionsToCover[currentIndex]));
if (currentCombination[currentDimensionsToCover[currentIndex]] == currentCombination.GetDimensionSize(currentDimensionsToCover[currentIndex]) - 1)
{
currentCombination[currentDimensionsToCover[currentIndex]] = 0;
selectNext = true;
currentIndex--;
}
else
{
currentCombination[currentDimensionsToCover[currentIndex]]++;
selectNext = false;
}
}
return !selectNext || (currentIndex != -1);
}
public bool IsValid(DimensionValueIndexCombination combination, int targetDimensionIndex, int targetDimensionIndexValue)
{
return(IsValid(GetValueIndexes(combination, targetDimensionIndex, targetDimensionIndexValue)));
}
private IEnumerable <int> GetValueIndexes(DimensionValueIndexCombination combination, int targetDimensionIndex, int targetDimensionIndexValue)
{
return(Enumerable.Range(0, _dimensionIndexes.Count).Select(i => GetValueIndex(i, combination, targetDimensionIndex, targetDimensionIndexValue)));
}
/// <summary>
/// Explores the input (sub-)space. Each invocation may return a different set.
/// </summary>
/// <returns>
/// A (reasonably-sized) stream of vectors/values from the (sub-)space.
/// </returns>
public override IEnumerable <Vector> Explore()
{
if (TargetMatrix.Dimensions.Count == 0)
{
// No dimensions to explore, then yield one empty vector.
yield return(new Vector());
yield break;
}
ReadOnlyCollection <DimensionWithValues> dimensionValues = GetAllDimensionValues();
if (dimensionValues.Any(dim => dim.Values.Count == 0))
{
yield break; // One of the dimensions is empty
}
if (dimensionValues.Count < _order)
{
// This is really non-sensical to ask for an n-wise strategy for a matrix with less than n dimensions
// but I'd rather return a good default than throw. So I'll just cheat and do an exhaustive strategy instead
ExhaustiveCombinatorialStrategy exhaustiveStrategy = new ExhaustiveCombinatorialStrategy(this);
foreach (Vector v in exhaustiveStrategy.Explore())
{
yield return(v);
}
yield break;
}
CoveredPairwiseCombinations coveredCombinations = new CoveredPairwiseCombinations();
DimensionValueIndexCombination currentCombination = new DimensionValueIndexCombination(dimensionValues);
DimensionIndexCombinationGenerator dimensionIndexGenerator = CreateDimensionIndexCombinationGenerator(dimensionValues);
Vector currentVector = currentCombination.GenerateVector();
if (IsValidVector(currentVector))
{
coveredCombinations.AddCoveredPairwiseCombinations(currentCombination, dimensionIndexGenerator);
yield return(currentVector);
}
PartialVectorConstraintChecker partialConstraintChecker = UsePartialConstraintChecker ?
new PartialVectorConstraintChecker(dimensionValues, Constraints) : null;
foreach (ReadOnlyCollection <int> currentDimensionsToCover in dimensionIndexGenerator.Generate())
{
// Initialize the selection of values in the newly selected pairwise combination
for (int i = 0; i < currentDimensionsToCover.Count; i++)
{
currentCombination[currentDimensionsToCover[i]] = 0;
}
while (true)
{
bool selectionSucceeded = SelectNextValuesForCurrentDimensionCombination(currentCombination, currentDimensionsToCover);
if (!selectionSucceeded)
{
// We exhausted all combinations of values for the current pairwise combination
// select the next pairwise combination
break;
}
if (coveredCombinations.IsCombinationCovered(currentDimensionsToCover, currentCombination))
{
continue;
}
if (partialConstraintChecker != null &&
!partialConstraintChecker.IsValidForApplicableConstraints(currentCombination, currentDimensionsToCover))
{
// This combination is forbidden by constraints - carry on
continue;
}
// Randomize other values, try at most MAXTRIES since we might hit invalid combinations
for (int i = 0; i < MAXTRIES; i++)
{
List <int> remainingDimensionIndexes = Enumerable.Range(0, dimensionValues.Count)
.Where(di => !currentDimensionsToCover.Contains(di)) // Don't randomize the pair currently worked on
.ToList();
RandomUtilities.ShuffleList(remainingDimensionIndexes, _nextInt);
List <int> setDimensionIndexes = new List <int>(currentDimensionsToCover);
foreach (int dimensionIndex in remainingDimensionIndexes)
{
ReadOnlyCollection <int> allowedValueIndexes = UsePartialConstraintChecker ?
partialConstraintChecker.GetAllowedValueIndexesForDimension(dimensionIndex, setDimensionIndexes, currentCombination) :
Enumerable.Range(0, currentCombination.GetDimensionSize(dimensionIndex)).ToList().AsReadOnly();
if (allowedValueIndexes.Count == 0)
{
break;
}
currentCombination[dimensionIndex] = allowedValueIndexes[_nextInt(allowedValueIndexes.Count)];
setDimensionIndexes.Add(dimensionIndex);
}
if (setDimensionIndexes.Count < dimensionValues.Count)
{
// Couldn't set all dimension values, try again (or quit)
continue;
}
currentVector = currentCombination.GenerateVector();
if (partialConstraintChecker != null || IsValidVector(currentVector))
{
coveredCombinations.AddCoveredPairwiseCombinations(currentCombination, dimensionIndexGenerator);
yield return(currentVector);
break; // Out of the MAXTRIES loop
}
}
}
}
}
/// <summary>
/// Encodes the given combination as a list of integers
/// </summary>
/// <param name="dimensionsOfInterest"></param>
/// <param name="combination"></param>
/// <returns></returns>
/// <remarks>
/// I'll just encode a covered combination like: {D4:2,D1:10} as {1,10,4,2} (sort on dimension index first).
/// </remarks>
private static List<int> EncodeCombination(ICollection<int> dimensionsOfInterest, DimensionValueIndexCombination combination)
{
List<int> sortedDimensions = new List<int>(dimensionsOfInterest);
sortedDimensions.Sort();
List<int> ret = new List<int>(dimensionsOfInterest.Count * 2);
foreach (int dimension in sortedDimensions)
{
ret.Add(dimension);
ret.Add(combination[dimension]);
}
return ret;
}
/// <summary>
/// Adds all the combinations of the given order as covered.
/// </summary>
/// <param name="combination">The combination to cover.</param>
/// <param name="dimensionIndexGenerator">The dimension index generator to use for getting all dimension index combinations we care about.</param>
public void AddCoveredPairwiseCombinations(DimensionValueIndexCombination combination, DimensionIndexCombinationGenerator dimensionIndexGenerator)
{
foreach (ReadOnlyCollection<int> dimensionsOfInterest in dimensionIndexGenerator.Generate())
{
if (!IsCombinationCovered(dimensionsOfInterest, combination))
_coveredCombinations.Add(EncodeCombination(dimensionsOfInterest, combination));
}
}
/// <summary>
/// Determines whether the given combination has already been covered.
/// </summary>
/// <param name="dimensionsOfInterest">The dimensions of interest.</param>
/// <param name="combination">The combination.</param>
/// <returns>
/// <c>true</c> if the given combination is already covered; otherwise, <c>false</c>.
/// </returns>
public bool IsCombinationCovered(ICollection<int> dimensionsOfInterest, DimensionValueIndexCombination combination)
{
List<int> encodedCombination = EncodeCombination(dimensionsOfInterest, combination);
foreach (List<int> covered in _coveredCombinations)
{
if (AreEqual(covered, encodedCombination))
return true;
}
return false;
}
/// <summary>
/// Checks if the vector so far is valid according to constraints.
/// </summary>
/// <param name="combination">The combination with the values chosen so far.</param>
/// <param name="setDimensionIndexes">The indexes of the dimensions where we have chosen values.</param>
/// <returns><c>true</c></returns>
public bool IsValidForApplicableConstraints(DimensionValueIndexCombination combination, IEnumerable<int> setDimensionIndexes)
{
return _extendedConstraints.Where(c => c.IsRelevantConstraint(setDimensionIndexes)).All(c => c.IsValid(combination));
}
/// <summary>
/// Encodes the given combination as a list of integers
/// </summary>
/// <param name="dimensionsOfInterest"></param>
/// <param name="combination"></param>
/// <returns></returns>
/// <remarks>
/// I'll just encode a covered combination like: {D4:2,D1:10} as {1,10,4,2} (sort on dimension index first).
/// </remarks>
private static List <int> EncodeCombination(ICollection <int> dimensionsOfInterest, DimensionValueIndexCombination combination)
{
List <int> sortedDimensions = new List <int>(dimensionsOfInterest);
sortedDimensions.Sort();
List <int> ret = new List <int>(dimensionsOfInterest.Count * 2);
foreach (int dimension in sortedDimensions)
{
ret.Add(dimension);
ret.Add(combination[dimension]);
}
return(ret);
}
private int GetValueIndex(int dimensionIndexIndex, DimensionValueIndexCombination combination, int targetDimensionIndex, int targetDimensionIndexValue)
{
return(_dimensionIndexes[dimensionIndexIndex] == targetDimensionIndex ? targetDimensionIndexValue : combination[_dimensionIndexes[dimensionIndexIndex]]);
}
private int GetValueIndex(int dimensionIndexIndex, DimensionValueIndexCombination combination, int targetDimensionIndex, int targetDimensionIndexValue)
{
return _dimensionIndexes[dimensionIndexIndex] == targetDimensionIndex ? targetDimensionIndexValue : combination[_dimensionIndexes[dimensionIndexIndex]];
}
private IEnumerable <int> GetValueIndexes(DimensionValueIndexCombination combination)
{
return(_dimensionIndexes.Select(d => combination[d]));
}
private IEnumerable<int> GetValueIndexes(DimensionValueIndexCombination combination, int targetDimensionIndex, int targetDimensionIndexValue)
{
return Enumerable.Range(0, _dimensionIndexes.Count).Select(i => GetValueIndex(i, combination, targetDimensionIndex, targetDimensionIndexValue));
}
public bool IsValid(DimensionValueIndexCombination combination)
{
return(IsValid(GetValueIndexes(combination)));
}
private IEnumerable<int> GetValueIndexes(DimensionValueIndexCombination combination)
{
return _dimensionIndexes.Select(d => combination[d]);
}
/// <summary>
/// Checks if the vector so far is valid according to constraints.
/// </summary>
/// <param name="combination">The combination with the values chosen so far.</param>
/// <param name="setDimensionIndexes">The indexes of the dimensions where we have chosen values.</param>
/// <returns><c>true</c></returns>
public bool IsValidForApplicableConstraints(DimensionValueIndexCombination combination, IEnumerable <int> setDimensionIndexes)
{
return(_extendedConstraints.Where(c => c.IsRelevantConstraint(setDimensionIndexes)).All(c => c.IsValid(combination)));
}
/// <summary>
/// Explores the input (sub-)space. Each invocation may return a different set.
/// </summary>
/// <returns>
/// A (reasonably-sized) stream of vectors/values from the (sub-)space.
/// </returns>
public override IEnumerable<Vector> Explore()
{
if (TargetMatrix.Dimensions.Count == 0)
{
// No dimensions to explore, then yield one empty vector.
yield return new Vector();
yield break;
}
ReadOnlyCollection<DimensionWithValues> dimensionValues = GetAllDimensionValues();
if (dimensionValues.Any(dim => dim.Values.Count == 0))
{
yield break; // One of the dimensions is empty
}
if (dimensionValues.Count < _order)
{
// This is really non-sensical to ask for an n-wise strategy for a matrix with less than n dimensions
// but I'd rather return a good default than throw. So I'll just cheat and do an exhaustive strategy instead
ExhaustiveCombinatorialStrategy exhaustiveStrategy = new ExhaustiveCombinatorialStrategy(this);
foreach (Vector v in exhaustiveStrategy.Explore())
yield return v;
yield break;
}
CoveredPairwiseCombinations coveredCombinations = new CoveredPairwiseCombinations();
DimensionValueIndexCombination currentCombination = new DimensionValueIndexCombination(dimensionValues);
DimensionIndexCombinationGenerator dimensionIndexGenerator = CreateDimensionIndexCombinationGenerator(dimensionValues);
Vector currentVector = currentCombination.GenerateVector();
if (IsValidVector(currentVector))
{
coveredCombinations.AddCoveredPairwiseCombinations(currentCombination, dimensionIndexGenerator);
yield return currentVector;
}
PartialVectorConstraintChecker partialConstraintChecker = UsePartialConstraintChecker ?
new PartialVectorConstraintChecker(dimensionValues, Constraints) : null;
foreach (ReadOnlyCollection<int> currentDimensionsToCover in dimensionIndexGenerator.Generate())
{
// Initialize the selection of values in the newly selected pairwise combination
for (int i = 0; i < currentDimensionsToCover.Count; i++)
{
currentCombination[currentDimensionsToCover[i]] = 0;
}
while (true)
{
bool selectionSucceeded = SelectNextValuesForCurrentDimensionCombination(currentCombination, currentDimensionsToCover);
if (!selectionSucceeded)
{
// We exhausted all combinations of values for the current pairwise combination
// select the next pairwise combination
break;
}
if (coveredCombinations.IsCombinationCovered(currentDimensionsToCover, currentCombination))
{
continue;
}
if (partialConstraintChecker != null &&
!partialConstraintChecker.IsValidForApplicableConstraints(currentCombination, currentDimensionsToCover))
{
// This combination is forbidden by constraints - carry on
continue;
}
// Randomize other values, try at most MAXTRIES since we might hit invalid combinations
for (int i = 0; i < MAXTRIES; i++)
{
List<int> remainingDimensionIndexes = Enumerable.Range(0, dimensionValues.Count)
.Where(di => !currentDimensionsToCover.Contains(di)) // Don't randomize the pair currently worked on
.ToList();
RandomUtilities.ShuffleList(remainingDimensionIndexes, _nextInt);
List<int> setDimensionIndexes = new List<int>(currentDimensionsToCover);
foreach (int dimensionIndex in remainingDimensionIndexes)
{
ReadOnlyCollection<int> allowedValueIndexes = UsePartialConstraintChecker ?
partialConstraintChecker.GetAllowedValueIndexesForDimension(dimensionIndex, setDimensionIndexes, currentCombination) :
Enumerable.Range(0, currentCombination.GetDimensionSize(dimensionIndex)).ToList().AsReadOnly();
if (allowedValueIndexes.Count == 0)
{
break;
}
currentCombination[dimensionIndex] = allowedValueIndexes[_nextInt(allowedValueIndexes.Count)];
setDimensionIndexes.Add(dimensionIndex);
}
if (setDimensionIndexes.Count < dimensionValues.Count)
{
// Couldn't set all dimension values, try again (or quit)
continue;
}
currentVector = currentCombination.GenerateVector();
if (partialConstraintChecker != null || IsValidVector(currentVector))
{
coveredCombinations.AddCoveredPairwiseCombinations(currentCombination, dimensionIndexGenerator);
yield return currentVector;
break; // Out of the MAXTRIES loop
}
}
}
}
}