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