mirror of
https://github.com/BlackLight/nash.git
synced 2024-12-27 09:35:11 +01:00
63 lines
2.4 KiB
Text
63 lines
2.4 KiB
Text
|
This is a small software that simulates the behaviour of a set of individuals
|
||
|
|
placed (for sake of simplicity) over a matrix where each individual can choose
|
||
|
|
between two strategies:
|
||
|
|
|
||
|
|
- Being cooperative with the other individuals
|
||
|
|
- Being in competition with the other individuals
|
||
|
|
|
||
|
|
From a certain starting point, in which each individuals has its own strategy
|
||
|
|
independantly from the one chosen by the others, the algorithm goes on, and a
|
||
|
|
certain individual x changes its strategy if there is a neighbour having a
|
||
|
|
different strategy and a higher "gain" value (i.e. that strategy takes more
|
||
|
|
benefit). The algorithm is repeated as long as an equilibrium point is reached
|
||
|
|
(Nash's equilibrium) in which no individual will change its strategy anymore as
|
||
|
|
no change is convenient anymore. This balance point won't be always reached
|
||
|
|
anyway, and the algorithm recognizes a scenario that has no Nash's equilibrium
|
||
|
|
point when a loop occurs (i.e. when it takes in exam a configuration that was
|
||
|
|
already met).
|
||
|
|
|
||
|
|
Usage of the program: compile simply issuing `make', then start it with
|
||
|
|
./nash <environment_file> <coop_coop_gain> <coop_comp_gain> <comp_coop_gain> <comp_comp_gain>
|
||
|
|
|
||
|
|
where
|
||
|
|
|
||
|
|
- environment_file is a file containing the starting configuration of the
|
||
|
|
environment (an example is included in the file `environment'). In this file the
|
||
|
|
collaborating individuals are marked by a dot `.', and the ones in competition
|
||
|
|
are marked by a `X'. Starting from here you can easily create your environment
|
||
|
|
file;
|
||
|
|
|
||
|
|
- coop_coop_gain: Score gained when the individual x cooperates and its neighbour
|
||
|
|
cooperates as well;
|
||
|
|
|
||
|
|
- coop_comp_gain: Score gained when the individual x cooperates and its neighbour
|
||
|
|
is in competition;
|
||
|
|
|
||
|
|
- comp_coop_gain: Score gained when the individual x is in competition and its
|
||
|
|
neighbour cooperates;
|
||
|
|
|
||
|
|
- comp_comp_gain: Score gained when both the individual x and its neighbour are
|
||
|
|
in competition.
|
||
|
|
|
||
|
|
An example is the problem of the two prisoners:
|
||
|
|
|
||
|
|
- When A doesn't confess and B doesn't confess too, they both get 8 years of
|
||
|
|
prison (coop_coop_gain = -8);
|
||
|
|
|
||
|
|
- When A doesn't confess and B confesses, A gets 20 years of prison and B is
|
||
|
|
free (coop_comp_gain = -20);
|
||
|
|
|
||
|
|
- When A confesses and B doesn't, A is free and B gets 20 years of prison
|
||
|
|
(comp_coop_gain = 0);
|
||
|
|
|
||
|
|
- When both A and B confess, they both get 14 years of prison (comp_comp_gain =
|
||
|
|
-14).
|
||
|
|
|
||
|
|
For running a simulation of the two prisoners' problem over the example
|
||
|
|
environment just type
|
||
|
|
|
||
|
|
./nash environment -8 -20 0 -14
|
||
|
|
|
||
|
|
Have fun.
|
||
|
|
|