Flibs'NFarol
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;; _________________________________________________________________________________________________________________ ;; ;; -------------------- FlibsN'Farol --------------------------------------------------------- FlibsN'Farol ;; FlibsN'Farol --------------------------------------------------------- FlibsN'Farol ----------------------- ;; _________________________________________________________________________________________________________________ breed [flibs flib] ;; FLiBs (finite living blobs) are the agents of the model: they are structured as ;; finite automata. They have "a finite number of states; an input signal ;; causes it to change automatically from one state to another. The kind of automaton ;; used in a flib also generates signals. Incoming and outgoing signals are represented ;; within the automaton by symbols. When a signal is received, the automaton changes ;; state and emits a second signal" (A. K. Dewdney, 1985) flibs-own [chromosome ;; every flib owns a chromosome, that is a string codifying its state transitions schema state ;; the current inner state of the flib choice ;; choice/prevision expressed by the flib regarding to go or not to go to the bar fitness ;; a measure of flibs' prevision ability to forestall if the bar will be crowded or not ] globals [tot_attend ;; total of attendances during one season to "El Farol" bar (i.e. 100 cycles tournement) sigma_attend ;; an accumulator for the previous variable crowded ;; a switch recording the state of the bar: 1 if overcrowded, 0 if not lorenz-points ;; list of the Lorenz curve ordinates gini-index-reserve;; counter functional to the calculation of the Gini index sigma-gini ;; an accumulator for the previous variable diversity ;; the number of the different chromosomes in the flibs population sigma_divers ;; an accumulator for the previous variable best ;; the best flibs fitness value worst ;; the worst flibs fitness value donor ;; one of best-performing flibs sharing part of its genes recipient ;; one flib acquiring genes from the donor flib a-split ;; the first cut in the recipient's chromosome b-split ;; the second cut in the recipient's chromosome locus ;; pointer/counter of chromosome loci ] ;; ---------- SETUP PROCEDURES ---------------------------------------------------------------------------------- ;; ------------------------------------------------------------------------------------------------------------------ to setup ;; initializing the model clear-all ;; create the bar area (yellow) and an elsewhere (blue) ask patches [set pcolor blue - 3] ask patches with [abs pxcor < 10 and abs pycor < 7] [set pcolor yellow] ask patches with [pxcor = 9 and pycor = 7] [set plabel ["El Farol Bar"]] ask patches with [pxcor = 21 and pycor = -21] [set plabel ["Elsewhere"]] ;; create the flibs and give them a random chromosome ask n-of num-flibs patches [sprout-flibs 1 [ set shape "flib" set color white set size 1.2 set chromosome "" ] ] set locus 0 ask flibs [chromosome-genesis] reset-ticks end ;; Chromosomes are strings randomly built through an iterative procedure. The content of even string positions ;; are 1 or 0: they are the flib's outgoing signals representing respectively the intention to go or not to go ;; to the bar. Odd string positions are occupied by the numerical code of one state. to chromosome-genesis set chromosome word chromosome (word (random 2) (random num-states)) set locus locus + 1 if locus < num-states * 2 [chromosome-genesis] set locus 0 end ;; ---------- RUNTIME PROCEDURES -------------------------------------------------------------------------------- ;; ------------------------------------------------------------------------------------------------------------------ to go set tot_attend 0 ask flibs [set fitness 0 set state 0] repeat 100 [el-farol] ;; a 100 cycles tournament could be seen as a season to "El Farol" bar (i.e. 100 evenings) if sum [fitness] of flibs = 0 [ ;; no fitness no progress show "fitness null for every flibs" stop ] analyse ;; some relevant "El Farol" seasonal results are picked and processed ask flibs [move] ;; the world displays a snapshot of the bar after the last evening of the season ;; after every season, one breeding and one mutational event occurs if best > worst [ if selective_reproduction = "by cloning" [cloning] if selective_reproduction = "by conjugation" [conjugation] ] ask one-of flibs [mutate] tick end ;; Operator 1: A SEASON TO EL FAROL BAR ;; ------------------------------------------------------------------------------------------------------------------- to el-farol let attendance 0 ;; the variable records the fraction of agents attending the bar during one evening flibs-behaviour ;; bar attendance is the sum of every flibs' choices set attendance sum [choice] of flibs / num-flibs ;; comparing the attendance and the threshold value, the (over)crowded state of the bar is determined if attendance >= threshold [set crowded 1 ;; if the bar is crowded, reward the flibs that are elsewhere ask flibs with [choice = 0] [set fitness fitness + 1] ] if attendance < threshold [set crowded 0 ;; if the bar is not crowded, reward the flibs that are attending ask flibs with [choice = 1] [set fitness fitness + 1] ] set tot_attend tot_attend + attendance ;; the results of every evening of a season is added up end to flibs-behaviour ask flibs [ ;; the flibs state is updated set state read-from-string item (4 * state + 2 * crowded + 1) chromosome ;; each flib processes its choice (to go or not to go) set choice read-from-string item (4 * state + 2 * crowded) chromosome ] end to analyse set best max [fitness] of flibs set worst min [fitness] of flibs ask flibs [set color scale-color red fitness 100 0] set sigma_attend sigma_attend + tot_attend / 100 update-lorenz-and-gini diversity-assessment set sigma_divers sigma_divers + diversity end to update-lorenz-and-gini ;; borrowed from Wilensky's model "Wealth Distribution" let sorted-comfort sort [fitness] of flibs let total-comfort sum sorted-comfort let comfort-sum-so-far 0 let index 0 set gini-index-reserve 0 set lorenz-points [] repeat num-flibs [ set comfort-sum-so-far (comfort-sum-so-far + item index sorted-comfort) set lorenz-points lput ((comfort-sum-so-far / total-comfort) * 100) lorenz-points set index (index + 1) set gini-index-reserve gini-index-reserve + (index / num-flibs) - (comfort-sum-so-far / total-comfort) ] set sigma-gini sigma-gini + ((gini-index-reserve / num-flibs) * 2) end to diversity-assessment ;; the value of genomic diversity inside the flibs population is evaluated as the number of different chromosomes let sort-chrom sort [chromosome] of flibs let index 1 set diversity 1 repeat num-flibs - 1 [ if item index sort-chrom != item (index - 1) sort-chrom [set diversity diversity + 1] set index (index + 1) ] end to move ifelse choice = 0 [move-to one-of patches with [pcolor = blue - 3]] [move-to one-of patches with [pcolor = yellow]] end ;; Operator 2: REPRODUCTION ;; ------------------------------------------------------------------------------------------------------------------- to conjugation ;; the conjugation process requires two flibs' chromosomes: the donor and the recipient: ;; just the second one will undergo to hybridization select-flibs ask flib recipient [ genetic-shuffling set fitness 0 ] end to cloning select-flibs ;; the conjugation process requires two flibs' chromosomes: the donor and the recipient ;; the genome of the first one will entirely replace the genome of the second one ask flib recipient [ set chromosome [chromosome] of flib donor set fitness 0 ] end to select-flibs set donor [who] of one-of flibs with [fitness = best] set recipient [who] of one-of flibs if donor = recipient [select-flibs] end to genetic-shuffling ;; a sequence included between two restriction sites (named a-split and b-split) is randomly chosen set a-split random (num-states * 4) set b-split random (num-states * 4) set locus 0 hybridization end to hybridization ;; the chromosome's sequence included between a-split and b-split restriction sites on a random ;; flib is replaced by the corresponding sequence on one of the most performing flibs; ;; chromosomes are treated as circular if a-split < b-split [ set chromosome replace-item (a-split + locus) chromosome (item (a-split + locus) [chromosome] of flib donor) set locus (locus + 1) if locus < b-split - a-split [hybridization] ] if a-split > b-split [ set chromosome replace-item ((a-split + locus) mod (num-states * 4)) chromosome (item ((a-split + locus) mod (num-states * 4)) [chromosome] of flib donor) set locus (locus + 1) if locus < (num-states * 4) - (a-split - b-split) [hybridization] ] set locus 0 end ;; Operator 3: MUTAGENESIS ;; ------------------------------------------------------------------------------------------------------------------- to mutate ;; mutations occur randomly at a given frequency on one locus only let dice random length chromosome let muton read-from-string item dice chromosome ifelse dice mod 2 = 0 [set chromosome replace-item dice chromosome word ((muton + 1) mod 2) ""] [set chromosome replace-item dice chromosome word ((muton + 1) mod num-states) ""] set fitness 0 end ; Copyright 2023 Cosimo Leuci. ; See Info tab for full copyright and license.
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Flibs'NFarol.png | preview | preview image | about 1 year ago, by Cosimo Leuci | Download |
READ_ME.txt | data | attachment | about 1 year ago, by Cosimo Leuci | Download |