mirror of
https://github.com/osmarks/random-stuff
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174 lines
4.3 KiB
Scheme
174 lines
4.3 KiB
Scheme
;; prisond.scm: iterated prisoner's dilemma simulation
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;; by matt
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;; this program is in the public domain
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(define strategies '())
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(define add-strategy
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(lambda (x y)
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(set! strategies (cons (cons x y) strategies))))
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(define angel
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(lambda (x y) 0))
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(define devil
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(lambda (x y) 1))
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(define tat-for-tit
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(lambda (x y)
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(if (null? x)
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1
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(if (= (car x) 0)
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1
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0))))
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(define tit-for-tat
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(lambda (x y)
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(if (null? x)
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0
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(car x))))
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(define time-machine
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(lambda (x y)
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(if (> 3 (length x))
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0
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(caddr x))))
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(define random-choice
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(lambda (x y)
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(random 2)))
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(define grudger
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(lambda (x y)
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(if (memq 1 x)
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1
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0)))
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(define angry-tit-for-tat
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(lambda (x y)
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(if (null? x)
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1
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(car x))))
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(define apl
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(lambda (x y)
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(if (null? x)
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1
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(if (= ( car y) 0)
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1
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0))))
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(define forgiving-grudge
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(lambda (x y) (let* (
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(defection-count (length (filter (lambda (m) (= m 1)) x)))
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(result (if (> defection-count 3) 1 0))
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) result)))
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(define (take n xs)
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(let loop ((n n) (xs xs) (zs (list)))
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(if (or (zero? n) (null? xs))
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(reverse zs)
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(loop (- n 1) (cdr xs)
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(cons (car xs) zs)))))
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(define (zip . xss) (apply map list xss))
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(define actually-forgiving-grudge
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(lambda (x y) (let* (
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(defection-count (length (filter (lambda (m) (= m 1)) x)))
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; TODO: tune 1.8 there, or maybe entirely switch out formula
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(lookback (+ 1 (inexact->exact (floor (expt 1.8 defection-count)))))
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; should maybe be (zip (append x '(-1)) (cons -1 y)) - current version compares actions at the same time, but it may not be "betrayal" unless the defecting by the opponent comes AFTER our cooperating
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; this does seem to worsen its score so maybe not
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(result (if (member '(1 0) (take lookback (zip x y))) 1 0))
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) result)))
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(define apiomemetics
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(lambda (x y) (random-seed 334278294) ; NOTE TO SELF: 3227883998 (0/2) or 2324865786 (48/50)
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(if (null? x)
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(begin 0)
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(if (> (length x) 93)
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1
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(car x)))))
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(define meapiometics
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(lambda (x y)
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(if (null? x)
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0
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(if (> (length x) 97)
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1
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(car x)))))
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(define prisond
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(lambda (x y)
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(if (= x y)
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(if (= x 1)
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'(-2 -2)
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'(-1 -1))
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(if (= x 1)
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'(0 -3)
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'(-3 0)))))
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(define iter-prisond
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(lambda (x y z)
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(define scores '(0 0))
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(define moves-x '())
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(define moves-y '())
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(define current-moves '())
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(define helper
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(lambda (x y z)
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(if (= z 0)
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scores
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(begin
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(set! current-moves (list (x moves-x moves-y) (y moves-y moves-x)))
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(set! moves-x (cons (cadr current-moves) moves-x))
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(set! moves-y (cons (car current-moves) moves-y))
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(set! scores (map + scores (prisond (car current-moves) (cadr current-moves))))
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(helper x y (- z 1)))))) (helper x y z)))
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(define get-strategy-scores
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(lambda (x)
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(define score 0)
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(define iters (+ 100 (random 50)))
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(define helper
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(lambda (y)
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(if (eqv? (car x) (car y))
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0
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(set! score (+ score (car (iter-prisond (cdr x) (cdr y) iters)))))))
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(map helper strategies)
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score))
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(define get-repeated-score
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(lambda (strategy accumulator counter)
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(if (= counter 0) accumulator
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(get-repeated-score strategy
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(+ accumulator (get-strategy-scores strategy))
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(- counter 1)))))
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(define get-all-scores
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(lambda ()
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(define helper
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(lambda (x)
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(write (list (car x) (get-repeated-score x 0 50)))
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(newline)))
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(map helper strategies)))
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(add-strategy 'angel angel)
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(add-strategy 'devil devil)
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(add-strategy 'tit-for-tat tit-for-tat)
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(add-strategy 'tat-for-tit tat-for-tit)
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(add-strategy 'time-machine time-machine)
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(add-strategy 'random-choice random-choice)
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(add-strategy 'grudger grudger)
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(add-strategy 'angry-tit-for-tat angry-tit-for-tat)
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(add-strategy 'apl apl)
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(add-strategy 'meapiometics meapiometics)
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(add-strategy 'apiomemetics apiomemetics)
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(add-strategy 'forgiving-grudge forgiving-grudge)
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(add-strategy 'actually-forgiving-grudge actually-forgiving-grudge)
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(random-seed (time-second (current-time)))
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(get-all-scores)
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(exit)
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