private double EvaluateDiscards(int cards)
{
Debug.Assert(BitwiseCardHelper.GetCardCount(cards) == 12);
var values = new List <double>();
var enumerator = new TwoCardsEnumerator(cards);
while (enumerator.MoveNext())
{
int cardsAfterDiscarding = cards & ~enumerator.Current;
double value = EvaluateCards(cardsAfterDiscarding, enumerator.Current);
values.Add(value);
}
return(values.Max());
}
protected override double EvaluateCards(int cards, int discards)
{
Debug.Assert(BitwiseCardHelper.GetCardCount(cards) == 10);
int trumpCount = BitwiseCardHelper.GetSuitCount(cards, mTrumpSuit);
// Don't consider trump game if the number of trumps is less than 4.
// TODO Consider 3-3-3-1.
if (trumpCount < 4)
{
return(double.MinValue);
}
IEnumerable <TrickProbability> totalProbabilities = Enumerable.Empty <TrickProbability>();
// Calculate sum of tricks with corresponding probabilities in all suits.
for (var suit = CardSuit.Spades; suit <= CardSuit.Hearts; suit++)
{
int cardSet = BitwiseCardHelper.GetCardSet(cards, suit);
IEnumerable <TrickProbability> probabilities = TrickPlayProbabilities.GetTrickProbabilities(cardSet);
// Combine probabilities..
totalProbabilities = totalProbabilities.Combine(probabilities);
}
bool isEasyLevel = (Game.Options.DifficultyLevel == GameDifficultyLevel.Beginner) ||
(Game.Options.DifficultyLevel == GameDifficultyLevel.Amateur);
// The following stuff is too complex for weak players.
if (!isEasyLevel)
{
totalProbabilities = ConsiderTrumpAdvancing(totalProbabilities);
totalProbabilities = ConsiderTrickTaking(totalProbabilities);
}
return(totalProbabilities.Expectation(
tricks => Game.Rules.GetGameCost(
GameType.TrickPlay,
Game.Options.NumberOfPlayers,
DeclaredTricks,
tricks)));
}
/// <summary>
/// Calculates a mathematical expectation of the active hand for a certain game type.
/// Uses the expecti-max algorithm to compute the value among all possible widow cards and further discards.
/// Updates the <see cref="Expectation"/> property.
/// </summary>
/// <returns></returns>
internal void Evaluate()
{
int ownCards = BitwiseCardHelper.CardCollectionToBits(mGame.ActiveHand.Cards);
int unknownCards = ~ownCards;
Debug.Assert(BitwiseCardHelper.GetCardCount(unknownCards) == 22);
var values = new List <double>();
var enumerator = new TwoCardsEnumerator(unknownCards);
while (enumerator.MoveNext())
{
int ownCardsWithWidow = ownCards | enumerator.Current;
double value = EvaluateDiscards(ownCardsWithWidow);
values.Add(value);
}
Expectation = values.Average();
}
internal void RemoveCards(int cards)
{
mCards &= ~cards;
mCount = BitwiseCardHelper.GetCardCount(mCards);
}
internal CardSet(int cards)
{
mCards = cards;
mCount = BitwiseCardHelper.GetCardCount(cards);
}