sim_EWA() simulates plays of a normal-form game expected by an experienced weighted attraction (EWA) model.

sim_EWA(
  game,
  n_periods,
  lambda = 1,
  delta = 0.5,
  rho = 0.5,
  phi = 0.5,
  A1_init = 0,
  A2_init = 0,
  N_init = 0
)

Arguments

game

An object of normal_form class defined by normal_form().

n_periods

A positive integer specifying how many times the game is played within each sample.

lambda

A positive real value representing the players' sensitivity to attraction values of strategies. As lambda gets larger, the choice will be dependent on attraction values more heavily. As lambda gets close to 0, a strategy will tend to be chosen randomly.

delta

A real number between 0 and 1. This parameter controls how fast attraction values of strategies that are not chosen are updated. If delta = 0, attraction is updated only for the strategy that is selected at the given period (i.e., reinforcement learning is implemented). If delta = 1, attraction is updated equally for all strategies (i.e., belief-based learning model is applied).

rho

A real value between 0 and 1. This parameter controls the learning speed. rho = 0 for "reinforcement" leaning and "belief" based learning.

phi

A real value between 0 and 1. This parameter controls how much attraction values at the current period are constrained by the past attraction values. If phi = 0, the past attraction values are ignored. phi = 1 for "reinforcement" leaning and "belief" based learning.

A1_init

An initial value of Player 1's attraction for each strategy.

A2_init

An initial value of Player 2's attraction for each strategy.

N_init

An initial value of N.

Details

Simulate plays of a normal-form game defined by normal_form() in a way expected by an EWA model.

Author

Yoshio Kamijo and Yuki Yanai yanai.yuki@kochi-tech.ac.jp