How to loop in NetLogo? - netlogo

Question

I have the following problem. I need to loop through the code. However, it doesn't work.
Contextualizing the problem: I have 3 files (in .asc) that represent data referring to 3 ages of the turtles (age 2, age 4 and age 8). I would like if the user puts the value 1 in num-user, it would only do the simulation with only one file (L_2) that would represent [ "2" ] ; if the user puts the value 2 in num-user, he would do the simulation with the files (L_2 and L_4) that would represent [ "2" "4" ] and finally, if the user puts the value 3 in num-use, it would simulate the files (L_2 , L_4 and L_8) that would represent [ "2" "4" "8" ]. The problem is that the loop is not working and gives various errors. Like:
Extension exception: ascii file ./L_8.asc not found or Can't find element 3 of the list [2 4 8], which is only of length 3 or go runs more than 3 simulations.
I was unable to attach the .ascii files here in the question. But if anyone can look at the code and identify the error I would be very grateful. I can't use BehaviouSpace to solve the situation, I need this loop in the code.
Thanks in advance!
extensions [ gis ]
globals [ num turtle-ages num-ages files random-seeds num-user repetitions ]
to setup
ca
set random-seeds 1
random-seed random-seeds
set num 0
set turtle-ages [ "2" "4" "8" ]
set num-ages item num turtle-ages
setup-asc
setup-turtles
reset-ticks
end
to setup-2
clear
random-seed random-seeds
set num-ages item num turtle-ages
setup-asc
setup-turtles
reset-ticks
end
to setup-turtles
ask n-of 5 patches [ sprout 1 ]
end
to clear
set files 0
clear-ticks
clear-turtles
end
to setup-asc
let number1 num-ages
set files gis:load-dataset ( word "./L_" number1 ".asc" ) ;; this loads a one raster file. There are 3 files in the folder with the names: (L_2.asc ; L_4.asc and L_8.asc
end
to go
move
tick
let n count turtles
if n = 0 or ticks = 10
[
set random-seeds random-seeds + 1
set repetitions 1
if random-seeds = repetitions + 1
[
set random-seeds 1
set num num + 1
;; if the user puts the value 1 in num-user, it would only do the simulation with only one file (L_2) that would represent [ "2" ]
;;; if the user puts the value 2 in num-user, he would do the simulation with the files (L_2 and L_4) that would represent [ "2" "4" ]
;;;; and finally, if the user puts the value 3 in num-use, it would simulate the files (L_2 , L_4 and L_8) that would represent [ "2" "4" "8" ]
set num-user 1 ;;
if num = num-user [ stop ]
]
setup-2
]
end
to move
ask turtles [
right random 360
fd 1
if ticks = 5 [ die ]
]
end

Answer 1

Whenever possible, I'd suggest paring down your code to a MRE to a) make sure that users here can run your code (without your files, for example, this is not really viable) and b) to see if reframing your question / goals in simpler terms would help get things working- at least that's what works for me!
I think that you might find foreach useful here as a way to loop through your desired simulations instead of manually tracking the number of iterations. For this example, assuming num-user is a numeric input widget on the interface, the setup below will determine which of the ages to process:
globals [ ages-to-run ]
to base-setup
ca
; Determine how many simulations to run, based on user input into
; 'num-user' numerical input widget on the interface
ifelse num-user < 1 or num-user > 3 [
print "Incorrect number of simulations indicated"
] [
let possible-sims [ "2" "4" "8" ]
set ages-to-run sublist possible-sims 0 num-user
]
reset-ticks
end
After running the above, the ages-to-run variable will contain ["2"], ["2" "4"], or ["2" "4" "8"]. Next, you can iterate over those desired ages to run your simulations (a little more detail in comments):
to run-simulations
if ages-to-run = 0 [
print "Simulation setup not complete"
]
foreach ages-to-run [
; This is the loop proper where each "age" is iterated.
; All of your simulation calls (manual variable resetting,
; etc) should all go within this loop.
current-age ->
print word "Running simulations for age: " current-age
let file-to-load ( word "./L_" current-age ".asc" )
print file-to-load
clear-turtles
ask n-of 5 patches [
sprout 1 [
pd
set color runresult current-age + 55
]
]
repeat 20 [
ask turtles [
rt random 60 - 30
fd 1
]
tick
]
print ( word "Simulations complete for age: " current-age "\n" )
]
end
Running that code above with 3 entered into num-user will run a simulation for each age (different colors indicate different runs):
So to run simulations proper, all your per-age code should go within that foreach loop indicated above- and be careful, as you were in your question, to not reset global variables.