Usage

Installation

To use stratpy, first install it using pip:

$ pip install stratpy

Creating games

To create a new game use the Game() constructor:

Optional parameters:

title: title of the game which will be used during export.

players: number of players in the game (default is 2)

Example:

>>> from stratpy import *
>>> my_game = Game(title="My Game", players=2)
>>> game2 = Game("Prisoner's Dilemma")

Players

When the game is created the amount of players specified (default 2) are created as a vector in the game object.

You can access these players with my_game.player[1]

my_game.player[0] is reserved for Nature.

Player 1 is thus: my_game.player[1] and

Player 2 is: my_game.player[2]

these references can also be store in variables for convenience:

>>> nature = game.player[0]
>>> p1 = game.player[1]
>>> p2 = game.player[2]

Further names can be set using the names field:

>>> p1.name = "Japan"
>>> game.player[2].name = "South Korea"

Decision Nodes

Decision nodes are created with the Decision(player, name) constructor:

parameters:

player: The player the decision belongs to

name: the name of the decision (used when displaying the game)

utility: Used for endnodes to set the players’ utility as a tuple of floats

variable: Used for endnodes to set the players’ utility as a tuple of variables

Example:

>>> d1 = Decision(p1, "Commit")
>>> d2 = Decision(game.player[2], "Renege")
>>> d3 = Decision(p1, "Retaliate", utility=(3,3))
>>> v1, v2 = Variable("C_1"), Variable("C_2")
>>> d3 = Decision(p1, "Cooperate", utility=(v1,v2))

Variables

To create variables to be used for the players utility, use the Variable() constructor.

Variables require a name parameter used when displaying the payout.

name: name of the variable as a string (e.x. “X”)

If exporting to latex you can use latex syntax such as “C_2” to get C₂

Preference between variable utility can be ordered using the ‘>’ and ‘==’ operators.

Example:

>>> a = Variable("A")
>>> b = Variable("B")
>>> c = Variable("C")
>>> a > b == c

This results in players preferring a over b and c, and being indifferent to b and c.