Preflop expert system

When it is Loki's (either Loki-1 or Loki-2) first chance to act in the preflop, Loki uses a rule-based expert system to select one of four defined preflop strategies (or six if Loki is the small blind). These strategies determine the number of bets Loki will call and under which conditions it will bet/raise. The selection of the preflop betting strategy is based on the average return on investment (income rate) of Loki's hole cards, and thresholds defined by linear formulas using expert values. The income rate of all the two-card hands was determined with off-line simulations. The linear formulas take into account the expected number of players (players who will play the hand), Loki's position on the table, and the tightness of Loki. The tightness is a parameter that specifies the percentage of hands that Loki will play. There are three settings for this parameter: tight, moderate and loose. The most aggressive strategy whose threshold is less than or equal to the income rate of Loki's hand is selected.

For example, assume that Loki's is in the dealer's position (last player to act) and its hole cards are A $\heartsuit$-8 $\heartsuit$. There are four players still active in the game and Loki's tightness has been defined as moderate. The income rate value of Loki's hand obtained by a table lookup is 338. By using the linear formulas, we calculate that the thresholds for the four strategies from the most aggressive to the most passive one are $[M4=580, M2=200, M1=50, M0=-\infty]$. Thus, Loki's preflop strategy in this case is M2, since $200 \leq 338 < 580$. With the M2 preflop strategy, Loki will raise if there have been less than two bet/raises in the round, otherwise it will call.