I have a model of tax evasion where the taxes should be payed each round, e.g. each 1000 ticks. As a placeholder, I have this code
ask traders with [ticks = 1000 or ticks = 2000 or ticks = 3000];; Can this be set using a seed?
[reset-parameters
pay-taxes
revise-behavior
reset-turnover]
In SQL, I would have set done something like this:
FOR I IN 1..3000 LOOP
ask traders with ticks = I*1000
Is there a similar function in Netlogo? Any other tips on how to make something happen every 1000 ticks?
Your own solution will work, but is not optimal.
Since ticks is a global NetLogo reporter, and not a traders variable, the value returned by ticks mod 1000 = 0 does not vary with each trader. It will either be true for all of them or false for all of them, so there is no use putting in in a with clause (where it will be re-evaluated for each trader).
It would be faster (and clearer) to just do:
if ticks mod 1000 = 0 [
ask traders [
do-something
]
]
Finally wrapped my head around a simple sollution:
ask traders with [ticks mod 1000 = 0]
A very simple solution to this problem that could even be tracked later on would to be a code like this
turtles-own [tradetime];;used to calculate time or can be changes to any variable
to go ;;or where ever
set tradetime tradetime + 1
ask traders [if (tradetime = 1000)[do-something]
end
or if you want to only have that value for traders then you can do this
turtles-own [tradetime]
to go
ask traders [set tradetime tradetime + 1]
ask traders [if (tradetime = 1000)[do-something]
end
Hope this helped
Related
I'm new to NetLogo and I'm trying to create 2 sub-breeds (denoted by different shapes) within each breed for 2 breeds total (i.e. sharks and fishes). The chunks of code work as expected when ran individually, however, when running both chunks the first sub-breed of the fishes does not seem to initialise in the interface tab. For some reason the initialisation of the shark breed seems to interfere with the initiation of the fishes breed.
Any idea what i'm doing wrong? Code below.
; Create the agents
breed [sharks shark]
breed [fishes fish]
; Create the agents' variables
fishes-own
[
x0
y0
]
globals
[
species
species-f
]
to setup
; Always start with this
clear-all
reset-ticks
; Create sharks and species
create-sharks N-sharks ; N-sharks is a slider
[
set color blue
setxy random-xcor random-ycor
set species N-sharks
ask sharks
[
set shape "default"
set size 2.5
]
ask sharks with [who >= (species * (1 / 2))]
[
set shape "square"
set size 2
]
ask sharks with [who < (species * (1 / 6))]
[
set shape "star"
set size 3
]
] ; End create sharks and species
; Create fishes
create-fishes N-fishes
[
setxy random-xcor random-ycor
set x0 xcor
set y0 ycor
set species-f (N-fishes * species-ratio)
ifelse who <= species-f
[
set shape "sheep"
set size 5
]
[
set shape "cow"
set size 3
]
set color white
] ; End create fishes
end
There seem to be a number of misunderstandings about what code is run when by NetLogo, and what some pieces of code do: when you use create-turtles *number* [*commands*] (or with breeds, as in your case), commands is run once by every turtle being created (first the new turtles are created, then they run the commands in turn).
That means that every time you use ask sharks within the create-sharks' command block, every new shark will ask all other sharks to set shape and size. For example, if you create 100 sharks, instead of setting the shape and size only once you are doing it 10,000 times (100 * 100).
So you need to put all those commands out of their respective create-<breed>'s command blocks; for example:
create-sharks N-sharks [
set color blue
setxy random-xcor random-ycor
]
ask sharks [
set size 2.5
]
ask sharks with [who >= (species * (1 / 2))] [
set shape "square"
set size 2
]
ask sharks with [who < (species * (1 / 6))] [
set shape "star"
set size 3
]
This is still improvable code, but it shows how to achieve exactly the same thing by doing it once and not doing it N-sharks ^ 2 times.
A better way to do it is to bring those commands back inside the create-<breed>'s command block, but letting each agent carry out the task for itself only. That is, without using ask sharks but using ifelse, so that each shark will check its own condition:
create-sharks N-sharks [
set color blue
setxy random-xcor random-ycor
(ifelse
who >= (species * (1 / 2)) ; the first condition
[set shape "square" set size 2]
who < (species * (1 / 6)) ; the second condition
[set shape "star" set size 3]
; else
[set size 2.5])
]
All of this applies to the other breed too.
It is generally said that using who is a sign that the code should be improved, but let's not focus on this now.
You will have noticed that I omitted the part where you set species N-sharks. This is because I think there is another misunderstanding here and it is not clear to me what you wanted to do: species (such as species-f for the other breed) is a global variable. You are basically asking each of the 100 sharks (again, 100 for example) to do the same thing: set the value of a global variable to equal the value of another global variable. In this case, you are asking each shark to set species 100. This seems very unnecessary, especially considering that N-sharks is a slider used for setup and thus probably won't be changed during the simulation (which means that there is probably no need to store the current value of N-sharks as a separate global variable).
Why are you basing the repartition of your sub-breeds on the value of species? What do you want species to represent? Is it correct for it to be a separate variable from N-sharks? If yes, then it is not clear what is its point; if no, then it can be eliminated.
You need to make sure that whatever you wanted to do with N-sharks & species, and with N-fishes and species-f, is better reflected in your code.
Also because I think this is the reason why your first fish sub-breed isn't showing. First of all, what is species-ratio? It is not present in your example, but it seems to be relevant for your question. In any case, if your first fish sub-breed isn't showing, it means that there is no fish who satisfies the condition who <= species-f.
This doesn't surprise me. who numbers are progressive for turtles: if you create 15 sharks and later you create 10 fish...
... the oldest shark will have who = 0
... the youngest shark will have who = 14
... the oldest fish will have who = 15
... the youngest fish will have who = 24
As you can see in this example, there is no fish for which who <= N-fishes (where N-fishes = 10). Let alone that in your case you set species-f (N-fishes * species-ratio) and, although you didn't tell what species-ratio is, I imagine it is a value between 0 and 1 - thus making the value of species-f even smaller.
The problem is that you are using who to determine your fishes. To quote the Netlogo programming guide: "Who numbers are assigned irrespective of breeds. If you already have a frog 0, then the first mouse will be mouse 1, not mouse 0, since the who number 0 is already taken."
As such, you need to take the number of sharks into account for determining the cutoff point for your fish species
set species-f (N-fishes * species-ratio) + N-sharks - 1
One other comment I have on your code is that you use the following structure:
create-sharks N-shark [
ask sharks [...]
]
Every shark executes the entire command block of create-sharks. That means that every shark asks every shark to do something. Thus follows that every shark sets their shape to default N-shark times.
It is much more efficient to use one of the following constructions
create-sharks N-shark [...]
ask sharks [...]
or
create-sharks N-shark [
if <condition> [<reshape-self>]
]
I want a little help. I want turtles to cooperate with 50% probability if their land parcels are > 5.
I am writing as
ifelse random 1 = 0 and land > 5
[set cooperate? true]
[set cooperate? false]
But it gives error that; The > operator can only be used on two numbers, two strings, or two agents of the same type, but not on a string and a number.
how to correct it?
Thanks
There's not quite enough information to diagnose the problem. Is this code inside an ask turtles block with the variable 'land' as a turtles-own attribute? Also, you might want to print off some values of 'land' to make sure you actually have numbers in it.
As you can see from the working example below, there is no error in the code you have provided.
turtles-own [ land cooperate? ]
to testme
clear-all
create-turtles 10
[ set land random 10
ifelse random 1 = 0 and land > 5
[ set cooperate? true ]
[ set cooperate? false ]
]
type "Cooperating: " print count turtles with [cooperate?]
type "Not cooperating: " print count turtles with [not cooperate?]
end
I am trying to implement a timer for each turtle in Netlogo
so I can take the minimum value, maximum and average time taken for each turtle.
Can anyone help
You haven't said what you actually want timed (or given any code attempt). Any time you need a turtle to remember anything from one tick to the next, you need a variable. The simplest code for a timer is to have a variable that you set to the current value of ticks when the process starts and subtract that start time from the current value of ticks when the process stops. Here is a complete model example:
turtles-own
[ start-time
time-taken
]
to setup
clear-all
create-turtles 20
[ set start-time 2 + random 10
set time-taken -1
]
reset-ticks
end
to go
let movers turtles with [time-taken = -1 and start-time <= ticks]
ask movers
[ set heading random 360
forward 1 + random 3
if random-float 1 < 0.05 [ set time-taken ticks - start-time ]
]
tick
end
And check out the new Time extension if you want your timers to use real time units (seconds, minutes, years...) and have non-integer values.
https://github.com/NetLogo/Time-Extension
Look at primitives such as time:difference-between
For example, you could do this coding that flags the turtle you want to monitor and increments the flag variable when an event occurs. You can then monitor it in the BehaviorSpace and analyses the results output in a csv file. For example, the following codes:
globals [ID]
turtles-own [special-turtle]
to create-turtle
crt 1 [
setxy min-pxcor 0
set heading 90
set special-turtle false
set ID who]
end
to go
;omitted
special-turtles
tick
end
to special-turtles
ask turtles-on patch 0 0 [set ID who]
ask max-one-of turtles [who] [set special-turtle true]
ask turtles with [special-turtle = true][set special-turtle (special-turtle + 1)]
end
I think there is something that none of the previous answers considered: the way you implement your timer depends on how you want to use the measurement.
1 - If you want to read the measurement only after the measurement is completed
The expression "after the measurement is completed" can mean both that you want to read it at some point later during the model, or maybe even just from some model's output.
The approach I'd take in this case is similar to what JenB suggested, but I believe you can put it a bit simpler because here I only use one extra turtle variable (apart from my-variable, that is there only to represent something that you already have in your model):
turtles-own [
my-variable ; This represents something you have in your model, to be used as a condition for the timer
my-timer
]
to setup
clear-all
reset-ticks
create-turtles 10
end
to go
; Here you have your normal code. When you need, just include
; 'start-timer' and 'stop-timer'. For simplicity, let's
; say you want to count how long does each turtle take
; to get from a value of 1 to a value of 5 for my-variable.
; You can just do:
ask turtles [
if (random 10 < 2) [
set my-variable (my-variable + 1)
]
if (my-variable = 1) [
start-timer
]
if (my-variable = 5) [
stop-timer
type "I am turtle " type who type " and it took me " type my-timer print " ticks."
die
]
]
tick
if (not any? turtles) [stop]
end
to start-timer
set my-timer ticks
end
to stop-timer
set my-timer (ticks - my-timer)
end
Note that most of the code is there only to make a full reproducible example, but the actual implementation only consists of my-timer, to start-timer and to stop-timer.
You can take this approach because the hypothesis here is that you will be interested in reading the measurement only after to stop-timer happened.
Otherwise, see point 2.
2 - If you want to be able to read the measurement at any moment during the simulation
In this case, you need to make the timer progress as time progresses (as opposed to point 1, where you could just take the initial and final time, and make the difference between the two).
I guess the easiest way to do this is to conditionally increment the timer every time there is a tick.
Taking the same example as before, it would be something like:
turtles-own [
my-variable ; This represents something you have in your model, to be used as a condition for the timer
timer-active?
my-timer
]
to setup
clear-all
reset-ticks
create-turtles 10 [
set timer-active? FALSE
]
end
to go
ask turtles [
if (random 10 < 2) [
set my-variable (my-variable + 1)
]
if (my-variable = 1) [
set timer-active? TRUE
]
if (my-variable = 5) [
set timer-active? FALSE
]
]
tick
ask turtles with [timer-active?] [
set my-timer (my-timer + 1)
]
if (count turtles with [my-variable < 5] = 0) [stop]
end
This way, you will be able to see at any moment what is the current value of my-timer for each turtle.
I was able to include the recovery or die but now I'm having trouble getting the standard deviation and of the turtles that died. I think I got the standard deviation but can't get the mean
if random-float 1 < recover-or-die [
set epi-state recovered-code
set color green
ifelse random-float 1 < 0.90[
]
]
]
I tried this for the mean and it kept saying "Expected Command"
Your problem is ifelse recovery-prob < 0.1 = true. I don't know what your recovery-prob is set to, but this line is always true or always false. What you probably want to do (and what is in your comment) is:
ask turtles with [epi-state = infectious-code]
[ ifelse random-float 1 < recovery-prob
[ set epi-state recovered-code
set color green
]
[ die
]
]
Note that you don't need to actually have the = true part.
If you have recover-prob set to 0.05 (for example), the condition is true for all turtles and they all recover. If it's set to 0.2 (for example), it is false for all turtles and they all die.
This block still has a logic problem I think. The way you have it written, any infectious turtle will either recover or die immediately. What about the turtles who stay infectious for more than one tick?
I would like to make the sum = the total of pollen recieved by a plant from other plants (Donnors) which is stored in a list of a list (own by each turtle = plant).
The following code make an error (when computing the sum):
OF expected input to be an agent or agentset but got the list
[[119.05593 50 50] [301.25853 50 50] [30.23906 50 50] [460.525845 50
50] [55.16717 50 50] [301.25853 50 50]] instead.
Does any one could help me about the mistake in the line "set Tot_pol sum ..." ?
Many thanks for your help.
to check-pol [m] ;; we check the pollen recieved by the two morphs
set Donnors [] ;; empty list of pollen donnors
ask zsps with [morph = m] ;; morph of the pollen reciever
[
set totpol 0
;; check for pollen donnors and morph for compatiblity within a radius :
ask zsps with[distance myself <= 20 and morph != m]
[
set totpol (NMaleFlowers * 100 * item round (distance myself) pollination-list) ;; the farther the less pollen
set Donnors lput [ (list totpol NMaleFlowers NFemFlowers)] of myself Donnors
]
set Tot_pol sum [ item (position 0 Donnors) Donnors ] of Donnors ;; total of pollen recieved
]
end
Luke's answer is good and should fix your problem. I suspect, however, that you are going to be doing lots of these types of sums. You may wish to set up a to-report that you can use for whichever item you want to sum over, just by passing the item number and the name of the list of lists. It would look like this:
to-report sum-item [#pos #listoflists ]
let items map [ x -> item #pos x ] #listoflists
report reduce [ [a b] -> a + b] items
end
The first line extracts the relevant item (remember index from 0) into a new list which the second line sums.
You would then use it with set Tot_pol sum-item 0 Donnors
Here's an answer that is not actually responding to your question. Instead, it is a more NetLogo-ish way of doing what I think you are trying to do with your code.
to check-pol [m]
ask zsps with [morph = m]
[ let senders zsps with [distance myself <= 20 and morph != m]
set totpol sum [NMaleFlowers * 100 * round (distance myself)] of senders
]
end
Your code gets into levels of ask that I think are unnecessary. What I think you are doing with your list is keeping track of the pollen donors. But an agentset is a cleaner approach and then you can simply pull out the information you want from the agentset using of.
Further, when you ask zsps with[distance myself <= 20 and morph != m] to set variable values in your code, then THOSE agents (not the receiving agent) are the ones having their variables changed. I think you are trying to take the perspective of the receiver of pollen, who looks around and received pollen from the other agents that are close enough. So the receiving agent should have the value changed.
This is not tested.
I'm not 100% sure what you're after here (you may want to look at the Minimum, Complete, and Verifiable Example guidelines), but if I'm reading you right you want the sum of the first item for each entry in the Donners list.
As to why your approach didn't work- NetLogo is telling you with that error that you've used of with a list, but of only works with agents or agentsets. Instead, you have to use a list processing approach. The simplest way might be to use sum in conjunction with map first in order to get what you need:
to sum-first-item
let example-list [ [ 1 2 3 ] [ 4 5 6 ] [ 7 8 9 ] ]
let sum-of-firsts sum map first example-list
print sum-of-firsts
end
To translate to Donnors, try:
set Tot_pol sum map first Donnors
That should work, but without reproducible a code example I can't check.