Computer Explorations of Fractals, Chaos,Complex Systems, and Adaptation

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 EIPD Documentation

```

```

#### NAME

```       eipd - simulate the ecological iterated Prisoner's Dilemma

```

#### SYNOPSIS

```       eipd -help
or
eipd   [-steps integer] [-rounds integer] [-seed  integer]
[-CC double] [-CD double] [-DC double] [-DD double]
[-Iallc  double]  [-Itft  double]  [-Irand  double]
[-Ipav   double]   [-Ialld  double]  [-rcp  double]
[-noise double]

```

#### DESCRIPTION

```       The ecological iterated Prisoner's  Dilemma  is  simulated
over time according to the specified parameters.  At every
time step the population of each strategy is calculated as
a  function  of  the  expected  scores  earned against all
strategies weighted by the populations of  the  opponents.
Possible  strategies  include  'Always Cooperate,' 'Always
Defect,'

```

#### OPTIONS

```       -steps integer
Number of steps to simulate.

-rounds integer
Number of rounds per step.

-seed integer
Random seed for initial state.

-CC double
Reward Payoff.

-CD double
Sucker Payoff.

-DC double
Temptation Payoff.

-DD double
Punish Payoff.

-Iallc double
Initial population of All-C.

-Itft double
Initial population of TFT.

-Irand double
Initial population of Random.

-Ipav double
Initial population of Pavlov.

-Ialld double
Initial population of All-D.

-rcp double
Probability of C for Random strategy.

-noise double
Probability of noise.

```

#### PAYOFFS

```       The payoff matrix for the Prisoner's Dilemma game is  usu-
ally expressed as:
Player B's Move
+-----------+-----------+
Player A's Move | cooperate |  defect   |
+-----------+-----------+-----------+
| cooperate |  CC, CC   |  CD, DC   |
+-----------+-----------+-----------+
|    defect |  DC, CD   |  DD, DD   |
+-----------+-----------+-----------+

where  the  table entries are (A's payoff, B's payoff) and
CC, CD, DC, and DD are the reward, sucker, temptation, and
punish payoffs, respectively.  For each of these four out-
comes you will probably want the payoffs  to  reflect  the
relationships:

(DC > CC > DD > CD) and ((CD + DC) / 2 < CC).

```

#### MISCELLANY

```       random noise (via the -noise option) manifests itself as a
cell making a randomly selected move in  a  single  round.
In  this  case,  both the cell whose action was altered as
well as that cell's opponents "remember" what  the  random
move was on the next round.

During  each time step, every strategy plays against every
other strategy as well as against itself.

The initial population levels for all strategies  will  be
normalized, so the scaling of the option values is irrele-
vant.

```

#### BUGS

```       No sanity checks are performed to make sure  that  any  of
the options make sense.

```

#### AUTHOR

```       Copyright (c) 1997, Gary William Flake.

Permission  granted  for any use according to the standard
GNU ``copyleft'' agreement provided that the author's com-
ments  are  neither  modified nor removed.  No warranty is
given or implied.
```