Netlogo Exercises

8/22/2019 Netlogo Exercises

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Un exemplu de program care creaza un numar de turtles si le misca intr-un loc cu iarba

verde, din care mananca.

Sunt doar doua butoane Setup si Go

turtles-own[energy] ;;variabila globalato Setup ;; to si end definesc functia (procedura)

clear-all

setup-patches

setup-turtles

reset-ticks

end

to setup-patches

ask patches [ set pcolor green ]

end

to setup-turtlescreate-turtles 25

ask turtles [ setxy random-xcor random-ycor ]

end

to Go

move-turtles

eat-grass

tick

end

to eat-grass

ask turtles

[if pcolor = green

[

set pcolor black

set energy energy + 10

]

]

end

to move-turtles

ask turtles

[right random 360

forward 1

set energy energy - 1

]

end

Programul poate fi dezvoltata prin adaugarea de monitoare, slidere, butoane si plot-uri.


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Monitoarele sunt campuri destinate sa afiseze o variabila globala.

Codul asociat cu monitorul e inclus in campul Reporter

Switch-urile se asociaza cu o variabila globala, definita chiar la nivelul switch-ului

Dar aceasta variabila trebuie testata undeva in program.

In cazul nostru, asta se face in functia eat-grass


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to eat-grass

ask turtles

[

if pcolor = green

[set pcolor black


]

ifelse show-energy?

[ set label energy ] ;; if show-energy switch is on (condition TRUE)

[ set label "" ] ;; is switch is off

]

end

Interesanta instructiunea ifelse care specifica ambele optiuni si pentru if si pentru else.Interesant si modul de folosire a proprietatii labela obiectelor din clasa turtle.

O varianta si mai complexa, in care agentii mananca se inmultesc sau mor, iar iarba

creste la loc dupa un timp.

Se modifica functia go, astfel:

to gomove-turtleseat-grassreproduce

check-deathregrow-grasstick ;; sa nu uitam acest tick!!!

end

Se observa ca au aparaut niste functii noi:

to reproduceask turtles[

if energy > 50[set energy energy - 50hatch 1 [ set energy 50 ]

]]

end

to check-deathask turtles[

if energy


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to regrow-grass

ask patches[if random 100 < 3 [ set pcolor green ]]

end

Observatii:

hatch ( a cloci, a scoate pui) este o primitiva Netlogo

hatch number [commands]

Se pare ca pozitia puiului este implict setata ca random (desi probabil este posibil ca in

secventa de comenzi asociata cu hatch sa se specifice si pozitia puiului.

die comanda omorarea turtles

Plotting

Nota: actualizarea plot-urilor se face la tick

Vrem sa adaugam o fereastra de plotting in care sa vizualizam evolutia unor variabile.

Incepem cu Add plot si definim axele si pen-urile pltului:

Apoi modificam functiile setup si go ca sa apeleze o functie noua do-plots.


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turtles-own[energy]

to Setup

clear-all

setup-patches

setup-turtlesreset-ticks

do-plots

end

to setup-patches

ask patches [ set pcolor green ]

end

to setup-turtles

create-turtles 1

ask turtles [ setxy random-xcor random-ycor ]

end

to go

move-turtles

eat-grass

reproduce

check-death

regrow-grass

tick ;; sa nu uitam acest tick!!!. Daca il

omitem, programul ruleaza OK, dar actualizarea imaginii

;; treuie setata pe 'continuous' - daca e pe on tick nu se

vede nimic!!do-plots

end

to eat-grass

ask turtles

[

if pcolor = green

[

set pcolor black


]ifelse show-energy?

[ set label energy ] ;; do this if switch is on

[ set label "" ] ;; do this if switch is off

]

end


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to move-turtles

ask turtles

[

right random 360

forward 1

set energy energy - 1]

end

to reproduce

ask turtles

[

if energy > 50

[

set energy energy - 50

hatch 1 [ set energy 50 ]

]

]

end

to check-death

ask turtles

[

if energy


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Tick counter

netlogo mentine o variabila globala implicita denumita ticks care se actualizeaza cu

numarul de pasi executati.

Poate fi testata in program, de exemplu pentru a iesi din bucle

to goif ticks >= 500 [ stop ]move-turtleseat-grasscheck-deathreproduceregrow-grasstick ;; aici se incrementeaza variabila ticksdo-plots

end

Comanda clear-all reseteaza contorul de tick-uri.

Sliders

Vrem sa modificam din inetrfata grafica valoarea initiala a numarului de turtles cu care

pornim si valoarea energetica a ierbii si energia puilor la nastere.

Incepem prin a adauga cele 3 slidere pe care le asociem cu niste variabile globale:

Dupa care modificam un pic codul:

to setup-turtlescreate-turtles number

ask turtles [ setxy random-xcor random-ycor ]end

to eat-grassask turtles [if pcolor = green [set pcolor blackset energy (energy + energy-from-grass)]


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ifelse show-energy?[ set label energy ][ set label "" ]]end

to reproduce

ask turtles[if energy > birth-energy[set energy energy - birth-energyhatch 1 [ set energy birth-energy ]]

]end

Despre BREED (rasa, specie)

In continuare analizez si comentez exemplu de cod Breeds and shapes din sectiuneaCode Examples

Pornim de la o interfata de genul asta:

Speciile (breeds) se definesc la inceputul zonei de cod inainte de orice procedura.

breed [monsters monster]breed [fish a-fish] ;; the word "fish" is both singular and plural,

;; so we need to use something different for

;; the singular formbreed [humans human] ;; bag si niste oamenibreed [rate o-rata] ;; si niste rate

Popularea cu turtles se face - in acest exemplu cu comanda sprout (a rasari, a germina)

care e asociata cu patches.


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to setupclear-all ;; clear all patches and turtlesset-default-shape monsters "monster" ;; shape is defined in Turtle Shapes Editorset-default-shape fish "fish" ;; dittoset-default-shape humans "boy"set-default-shape rate "bird2"

ask patches with [pxcor = 0] [ ;; just the middle column of patchesifelse random 2 = 0 ;; flip a coin[ sprout-monsters 1 ][ sprout-fish 1 ]

]ask patches with [pxcor = -1][if random 2 = 1[ sprout-humans 1 ]

]ask turtles [ ;; includes both monsters and fish

set heading 90 ;; face east]ask patches with [ pxcor > 5 and pycor > 4 ] [sprout-rate 1]

end

Comenzile de miscare:

to move-monsters

;; ask monsters [ fd 1 ]

ask monsters [ back random 3 ]

end

to move-fish

ask fish [ fd 1 ] ;; echivalent cu [ forward 1 ]

tick

end

to move-humans

ask humans [ fd 1]

ask humans [

if xcor > 4 [set shape "girl" ]]

tick

end


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Recapitulare:

- Pentru generarea/nasterea turtles am gasit 3 metode:a. cu comanda create-turtles how_many [commands...]

Observatii importante

1. Daca am definit o serie de breeds atunci putem invoca comanda create-turtles sub forma:

create-breed_name

De exemplu:

create-humans 25 [set color green]

- Agentii creati cu comanda create-turtles sunt pusi unul peste altul in patch-ul cu

coordonatele xcor=0 si ycor=0!!

- Ca sa-i dispersam e nevoie de ceva de genul urmator:create-humans 5 [ask humans [ setxy random-xcor random-ycor ] ]

ceea ce este echivalent cu:

create-humans 5

ask humans [ setxy random-xcor random-ycor ]

2. Forma (shape) agentilor se stabileste cu comanda:set-default-shape humans "boy" ;; denumirea formei pedefinite

b. Cu comanda sprout-sprout-turtles how_many

Comanda sprout este asociata cu patch-urile ( sprout inseamna a germina, ainmuguri, a da rod) deci trebuie invocata musai intr-un context de tipul:

ask patches with [pxcor = 0]

[ ;; just the middle column of patches

ifelse random 2 = 0 ;; flip a coin

[ sprout-monsters 1 ]

[ sprout-fish 1 ]

]

c. Cu comanda hatch how_many [ commands ]

Asta este asociata cu turtles (hatch inseamna a cloci, a face pui, a ecloza) si trebuie

invocata intr-un context de tipul ask turtles

Exemplu:

to reproduceask turtles[

if energy > 50[set energy energy - 50hatch 1 [ set energy 50 ]]

]end


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Pentru disparitia/moartea turtles exista urmatoarele posibilitati:

- comanda [ die ] invocata cu ask turtles, de exemplu:ask turtles [if age > 50 die]

- comanda clear- omoara toata specia si reseteaza contorul who

Pentru sistematizarea ideilor, facem un nou proiect denumit Miscari elementare

Gui-ul arata asa:

Si codul complet (lucrurile demne de atentie sunt marcate cu rosu):

breed [arrows arrow]

to setup

clear-all ;; clear all patches and turtles

set-default-shape arrows "arrow"

create-arrows 5 [ask arrows [ setxy random-xcor random-ycor ] ]

ask arrows [ set color red ]

ask turtles [ ;; includes both monsters and fish

set heading random 360 ;; zero grade inseamna in sus!!

]

end


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to rotate-left

ask arrows [ left 10 ]

tick

end

to rotate-rightask arrows [ right 10 ] ;;grade

tick

end

to Move-forward

ask arrows [ fd 0.5 ] ;; se poate misca si cu mai putin de o unitate per tick

tick

end

to Move-backask arrows [bk 0.5] ;; se poate misca si cu mai putin de o unitate per tick

tick

end

to auto

ask arrows [ left random 100 ]

ask arrows [ fd 0.5 ]

tick

end

Miscari elementare 2

Adaugam un slider care defineste si controleaza variabila globala speed .


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Observatie: Nu este nevoie sa redefinim in cod variabila globala asociata cu sliderul. Va

fi recunoscuta automat.

Procedura asociata cu butonul Auto se executa repetat, datorita unei proprietati a

butonului (exista un check-boc denumit Forever).

Codul se modifica in felul urmator:

to Move-forward

ask arrows [ fd speed ]

tick

end

to Move-back

ask arrows [bk speed]

tick

end

to auto



tick

end

Cate ceva despre adresarea individuala a agentilor

Cream un nou proiect denumit 3.Miscari elementare.nlogo, cu interfata grafica:


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Si codul asta:

breed [arrows arrow]

arrows-own [ speed ]

to setup

clear-all ;; clear all patches and turtlesset-default-shape arrows "arrow"

create-arrows 3 [ask arrows [ setxy random-xcor random-ycor ] ]

ask arrows [ set color red ]

ask turtles [ ;; includes both monsters and fish

set heading random 360

]

end

to rotate-left

ask arrows [ left 10 ]

tick

end

to rotate-right

ask arrows [ right 10 ]

tick

end

to auto



ask arrow 1 [ show speed ]

tick

end

Sunt cateva elemente noi aici:

1. Speed este o proprietate a agentilor individuali, definita imediat dupa breed.

arrows-own [ speed ]

2. Cand am definit butoanele, le-am asociat direct o bucatica de cod ca in figura:


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3. Comanda show afiseaza un mesaj (valoarea unei variabile de exemplu, in

fereastra de dialog din josul ferestrei de lucru)

In continuare sunt de analizat comenzile:

towardstowardsxyturtleturtlesturtle-setturtles-atturtles-onprintshow

writePornesc de la informatiile din manual si construiesc mici proiecte care sa ilustrezefunctiile respective.

Nota: Netlogo permite file I/O, de exemplu citirea unor configuratii de patches dintr-

un fisier.

Neighborhoods example

Interfata grafica arata asa:


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Exista doua noutati evidente in interfata asta:

Un text informativ static - note (Add, note)

Un cooser (drop down menu) care permite initializarea unei variabile globale cu valori

numerice sau string. In exemplul considerat e o variabila string.

Procedurile asociate cu butoanele au si ele o serie de particularitati interesante:

to setup

ca ;; echivalent cu clear-all

crt 8 ;; echivalent cu create 8

[ fd 10 ] ;; comanda inclusa in create

ask turtle 0 [ fd 7 ]



end

Modul de functionare a acestei proceduri: se simuleaza o distributie random a celor 8

turtles.

Comanda crt 8 creaza 8 turtles pe care le pune gramada in origine. Ele au totusi heading-

uri random, asa ca urmatoarea comanda [ forward 10 ] le muta pe toate inainte pe

directia initiala a fiecareia.

Rezulta o distributie destul de random.

Restul procedurilor sunt destinate sa ilustreze ideea de vecinatate se coloreaza patch-

urile din vecinatate, cu precizarea ca vecinatatea e definita in mai multe moduri.

Colorarea efectiva se face cu functia auxiliarapaint-agents [ agents ] :

to paint-agents [agents]

ask agents [ set pcolor [color] ofmyself + 2 ]

end

Aici avem nise noutati:

- Procedura are un parametru de intrare: [agents]

- apelarea ei se face in urmatoarele moduri:

a. Se specifica pur si simplu o lista de agenti ca in exemplul urmator:

paint-agents patches at-points [[1 1] [-1 1] [-1 -1] [1 -1 ]](nota: adresarea path-urilor in exemplul de mai sus este relativa la un punct curent. vezi

mai departe)

In afara de at-points, definirea subseturilor de agenti se mai poate face si cu operatori i:

with, at-points, in-radius, in-cone ;; reporters

b. ask turtles [ paint-agents patches in-radius radius ]

c. ask turtles [ paint-agents neighbors4 ]


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Codul complet:

;; This procedure creates 8 turtles in puts them in a circle,

;; and moves three to the edges of the worldto setup

cacrt 8

[ fd 10 ]




ask turtle 0 [ set color red ]

ask turtle 1 [ set color yellow ]

ask turtle 2 [ set color green ]

ask turtle 3 [ set color blue ]

ask turtle 4 [ set color gray ]

ask turtle 5 [ set color cyan ]

ask turtle 6 [ set color magenta ]

ask turtle 7 [ set color white ]

end

;; This procedure colors all the patches neighboring each turtle.

;; neighbors reports the eight patches surrounding the turtle.

;; Note that patches have neighbors as well, and can also use the neighbors reporter.to paint-neighbors

clear-patches

ask turtles [ paint-agents neighbors ]

end

;; This procedure is similar to paint-neighbors, but uses the neighbors4 reporter.;; neighbors4 reports only the four patches adjacent to the current patch, and does not include

;; the four neighbors which are only diagonally touching the current patch.

;; As with neighbors, both turtles and patches can use neighbors4.

to paint-neighbors4

clear-patches

ask turtles

[ paint-agents neighbors4 ]

end

;; This procedure uses in-radius to paint a "circle" around each turtle.

;; "agentset in-radius n" reports those agents in agentset whose distance from the current agent;; is less than or equal to n. For patches, distance is measured from the center of the patch.

;; Note that the caller can be a turtle or a patch, and agentset can be a set of turtles or a set of

;; patches, so you can also use in-radius to locate turtles within a given radius

;; of another turtle or patch. Also notice that the reported agentset includes the patch

;; that the turtle is currently on.


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to paint-in-radius

clear-patches

ask turtles

[ paint-agents patches in-radius radius ]

end

;; This procedure uses the at-points reporter to paint an arbitrary neighborhood.

;; at-points lets you specify groups of agents on individual patches, using points

;; relative to the calling agent (so [0 0] indicates the patch the agent is on).

;; As with the above primitives, at-points can be used by both turtles and patches.

to paint-at-points

clear-patches

ask turtles

[

if points = "corners"

[ paint-agents patches at-points [[1 1] [-1 1] [-1 -1] [1 -1 ]] ]

if points = "left"

[ paint-agents patches at-points [[-1 1] [-1 0] [-1 -1]] ]if points = "L-shape"

[ paint-agents patches at-points [[-1 1] [-1 0] [-1 -1] [0 -1] [1 -1 ]]]

if points = "line-up"

[ paint-agents patches at-points [[0 1] [0 2] [0 3] [0 4]] ]

]

end

;; This is a helper procedure, used to set the color of a set of patches.

to paint-agents [agents]

ask agents [ set pcolor [color] of myself + 2 ]

end

Note:

- Ideea de neighborhood (neighbor, neighbor4) se refera doar la patches.

- Nu e clar cum functioneaza paint-agents

Am rescris-o asa:

to paint-agents [which_agents]

ask which_agents [ set pcolor [color] of myself + 2 ]

end

Si merge.

Daca inlocuiesc myself cu self da eroare.

In schimb, daca lansez din command center comanda:


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ask turtle 0 [show [color] of self] - merge imi raspunde cu un numar codul culorii

ask turtle 0 [show [color] of myself]- da eroare!

Explicatia din manual suna asa:

"self" and "myself" are very different. "self" is simple; it means "me". "myself" means "theturtle or patch who asked me to do what I'm doing right now."

Exista un code example denumit "Myself Example" care explica mai multe.Daca elimin parantezele patrate din [color] iar da eroare.

Alta informatie extrasa din manual:

Formularea:

let new-color colorask turtle 0 [ set color new-color ]

este echivalenta cu:

ask turtle 0 [ set color [color] of myself ]

Am incercat sa lansez asta din centrul de comanda, din perspectiva turtles si merge.

Dar tot nu e clar cine e myself.

Daca lansez tot din perspectiva turtles comanda:

ask turtle 0 [show color]

primesc de N ori acelasi raspuns (N=numarul de turtles definit)

Iar comanda show who primeste raspuns de la toti agentii de tip turtle.

Din perspectiva observer, pot intreba:

show [color] of turtle 0

si primesc raspuns. [color] e un reporter, color e o proprietate.

Daca intreb show color din perspectiva turtles, primesc N raspunsuri, fiecare turtle isi

raporteaza culoarea.

Din perspectiva turtles, comenzile:

show color

show [color] of selfproduc acelasi rezultat cei N agenti isi raporteaza culoarea.

OK mergem mai departe cu exemplele: Box drawing example


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Box drawing example

Deci, avem o variabila globala edge definita de un slider si doua proceduri, setup-

corner si setup-center

Codul are putine noutati:

globals [halfedge]

;; setup procedure for case where point (0,0) is in the center of Box

to setup-center

ca ;; clear everything

set halfedge int (edge / 2)

ask patches[

if (pxcor = (- halfedge) and pycor >= (- halfedge) and pycor = (-

halfedge) and pycor = (- halfedge) and pxcor = (- halfedge) and pxcor


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Breed procedures.nlogo

;;defineste un caine, o pisica si o vaca mari (universul

e limitat la 3x3 celule)

breed [dogs dog]

breed [cats cat]breed [cows cow]

to setup

clear-all

set-default-shape dogs "dog"

set-default-shape cats "cat"

set-default-shape cows "cow"

ask patch 0 1 [ sprout-dogs 1 ]

ask patch 0 0 [ sprout-cats 1 ]

ask patch 0 -1 [ sprout-cows 1 ]

end

Asta e perfect echivalent cu (mai putin elegant):

breed [dogs dog]

breed [cats cat]

breed [cows cow]

to setup

clear-all

set-default-shape dogs "dog"

set-default-shape cats "cat"

set-default-shape cows "cow"

create-dogs 1 [set heading 0]

ask dogs [fd 1]

create-cats 1

create-cows 1 [set heading -180]

ask cows [fd 1]

end

si procedura go

to go

;; "turtles" refers to all of the turtles,

;; no matter what breed they are

ask turtles [

;; each turtle takes its breed, adds "-speak"

;; onto it, and then runs that procedure


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run word breed "-speak"

]

end

;; Here we have the separate procedure definitions

;; for each breed.

to dogs-speak ;; dog procedure

set label "arf arf!"

end

to cats-speak ;; cat procedure

set label "meow!"

end

to cows-speak ;; cow procedure

set label "mooooo!"

end

E interesanta smecheria, dar e echivalenta cu:

to go



ask turtles [

if (breed = dogs) [ set label "Ham"]

if (breed = cats) [ set label "Miau"]

if (breed = cows) [ set label "Muuu"]

]

end

si la fel de echivalenta cu asta:

to go



ask turtles [

ask dogs [set label "Ham"]

ask cats [set label "miau"]

ask cows [set label "Muuu!!"]

]

end


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Un prim exemplu care foloseste agenti de tip link Link Breeds Example.nlogo

Exista o singura procedura in proiect

Exemplul asta pare a fi important pentru ca ar putea fi nucleul unei aplicatii in care se

construieste o retea neuronala pornind de la un set de agenti conectati intre ei !!

;; every link breed must be declared as either directed or undirected

directed-link-breed [red-links red-link]

undirected-link-breed [blue-links blue-link]

blue-links-own [ weight ] ;; !!link breeds can own variables

to setup

clear-all

create-ordered-turtles 10 [

fd 5

set color gray

]

ask n-of 5 turtles [

;; create--with is used to make undirected links

create-blue-link-with one-of other turtles [

set color blue

set weight random 10

set label weight

]

]

;; different breeds can have different default shapesset-default-shape red-links "curved link"

ask n-of 5 turtles [

;; create--to/from are used to make directed links

create-red-link-to one-of other turtles [

set color red

]

]

end


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Cateva lucruri noi, de remarcat aici:

ask n-of number [command]

Se aplica o comanda unui numar specificat (number) de turtles

1.Hill Climbing Example.nlogo

Exemplul asta seamana mult cu ideea de a asocia patch-urile cu o altitudine (stocata in

tag-uri RFID) si de a instrui agentii (roboti) sa o ia la vale (downhill).

NetLogo are doua functii: uphill si downhill (cu variantele uphill4, downhill4)

Care comanda deplasarea agentului (turtle) intr-o casuta (patch) din vecinatate

(neighbors, sau neighbors4) care are un parametru specificat mai mare (uphill) sau mai

mic (downhill) decat casuta curenta.

Sintaxa este:

uphill patch_variable

Daca nu e nici o casuta in vecinatate care sa aiba o valoare mai mare decat

patch_variable, atunci agentul nu sse misca.

Daca sunt mai multe casute cu aceeasi valoare a patch_variable in vecinatate, se alege

una random.

Codul:turtles-own

[at_peak ;; indicates whether a turtle has reached a "peak",

;; that is, it can no longer go "uphill" from where it stands

]

to setup

clear-all

;; make a landscape with hills and valleys

ask n-of 10 patches [ set pcolor 120 ]

;; slightly smooth out the landscape


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repeat 20 [ diffuse pcolor 1 ]

;; put some turtles on patch centers in the landscape

ask n-of 30 patches [

sprout 1 [

set at_peak false

set color red

pen-down

]

]

end

to go

;; stop when all turtles are on peak

if all? turtles [at_peak]

[ stop ]

ask turtles [

;; remember where we started

let old-patch patch-here

;; to use UPHILL, the turtles specify a patch variable

uphill pcolor

;; are we still where we started? if so, we didn't;; move, so we must be on a peak

if old-patch = patch-here [ set at_peak true ]

]

tick

end

Sunt mai multe chestii interesante aici:

a. Specificatorul n-of

b. pcolor definita printr-un numar.


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c. Comanda diffuse percent/100

Se refera la patches dar e o comanda de observer. Se executa de toate patch-urile!

Exemplu:

diffuse chemical 0.5

;; each patch diffuses 50% of its variable;; chemical to its neighboring 8 patches. Thus,;; each patch gets 1/8 of 50% of the chemical;; from each neighboring patch.)

Asta merita un studiu separat, pentru ca feromonii difuzeaza.

d. repeat [commands ... ]

repeta lista de comenzi de numarul specificat de ori.

Exemplu:

pd repeat 36 [ fd 1 rt 10 ]

pd este prescurtarea de la pen-down

fd forward

rt right

Efectul este ca agentul deseneaza un cerc aproximat din 36 de segmente.

e.if all? turtles [at_peak]

if all? testeaza o conditie logica. Interesant ca e pusa in paranteze patrate.

f.let old-patch patch-here

Aici avem o metoda de a defini variabile locale.

Explicatia din manual:

letlet variable valueCreates a new local variable and gives it the given value. A local variable is one thatexists only within the enclosing block of commands.If you want to change the value afterwards, use set.

Deci conceptul de variabila locala se refera la ceva foarte local si volatil.

g.uphill pcolor

Deplasarea in sus in functie de culoarea patch-urilor din vecinatate


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Exemplu separat Diffuse_test.nlogo

Codul:

patches-own [pheromone]

to setup

clear-allask patch 0 0 [set pheromone 100]

ask patches [set plabel pheromone ]

end

to diffuse_once

diffuse pheromone 0.5

ask patches [set plabel precision pheromone 3 ]

end

Aici e interesant modul de a limita numarul de zecimale afisate folosind precision

precision number placesReports numberrounded to placesdecimal places

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