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
-8
.
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
.
Thus, Loki's preflop strategy in
this case
is *M*2, since
.
With the *M*2 preflop strategy,
Loki will raise if there have been less than two bet/raises in the round, otherwise it will call.