I write a traffic simulation program. I let the car move randomly within a 10m radius. What if the car out of that circle, I command die. but faulty program is not known to be driving function? how to tell if the patient dies vehicles with vehicles that died in this, the function is not called half?
if distancexy 0 0 >= 10
[
die
]
Ask all the cars with a distance greater than 10 die.
This is called from an observer's perspective.
ask cars with [(distancexy 0 0) > 10] [ die]
Related
I would like to change the minimum coordinate unit of the patch space, which is set to exist only one turtle per patch space, to less than one, and monitor it. We want to set the minimum spatial unit to the same tick size n as in tick-advance (e.g. n=0.1). Here is a piece of code, but it doesn't work. Can anyone help me? Thanks in advance.
globals [n] ; n<=1 i.e. n=0.1
; omitted
ask turtles [forward n]
tick-advance n
I find myself in the same boat as Matteo- I don't know that what you're looking to do is possible / makes sense in the context of NetLogo. The coordinates of patches are fixed (ie, one patch is one unit) but arbitrary (1 in Netlogo can mean 1 m or 1 km, depending on the model). In other words, a patch's coordinates are discrete, while turtles can move around in continuous space. So you can, of course, have a turtle wander around in step sizes of 1/10:
globals [n]
to setup
ca
set n 0.1
crt 10
reset-ticks
end
to go
ask turtles [
forward n
]
tick-advance n
end
After one run of go above, you could conceivably have a turtle at coordinates [xcor = 0.1, ycor = 0.1], although it would still be on patch 0 0 since pxcor values are integers.
It seems that what you are actually needing to do is not coming across as needed- can you edit your question to provide a little more detail / context? Perhaps knowing the why behind your need to model in this way will help askers get you pointed in the right direction. I personally am curious about:
Why you are using tick-advance instead of just tick
How you have implemented your one-turtle-per-patch restrictions- in other words, can you show a Minimal Reproducible Example? That may prompt other ways to approach what you're after.
Here is an example world with time tied to ticks:
globals [ seconds ]
to setup
ca
set seconds 0
resize-world 0 50 0 50
ask patches with [
floor (pxcor / 10) mod 2 + floor (pycor / 10) mod 2 = 1
] [
set pcolor white
]
crt 10
reset-ticks
end
to go
ask turtles [
fd 1
]
set seconds precision (seconds + 0.1) 2
if seconds mod 1 = 0 [print ( word "It has been " seconds " seconds.")]
tick
end
Currently the sharks and fish continue growing in size and speed what I'm attempting to do is have the energy for the fish and sharks go down more as they continue to move faster as as demonstrated with forward energy over 7 I'm also attempting to set a limit on the size the sharks and fish can reach
To go
update-plots
tick
ask sharks[
set Btimer (Btimer - 1)
forward Energy / 7
right random 80
left random 80
ask fishes[die]
set Energy (Energy + 7) ;this essentially controls speed making it so it will go faster if enough energy is collected
set size size + 0.1 ; this makes it so the sharks will continue growing and I'm not sure how to set a limit to the size they can grow to be
]
set Energy (Energy - 1)
if (Energy <= 0)[
die
]
if any? sharks-on patch-ahead 0 and Btimer <= 0[
ask sharks-on patch-ahead 0 [
set Btimer (Btimer + 400 - random 200)
set Energy (Energy - 50)
]
hatch 10 [
]
]
]
end
The basic problem appears to be that you increase speed every tick but don't have any code to stop growth. Here is one way to do it - you just have a test to see if the shark is fully grown:
to go
update-plots
tick
ask sharks
[ set Btimer (Btimer - 1)
forward Energy / 7
right random 80
left random 80
ask fishes [ die ]
if energy <= max-energy ; here is where you set the condition
[ set Energy (Energy + 7) ; also increases speed
set size size + 0.1
]
]
ask sharks ; There must be an ask here, otherwise error message
[ set Energy (Energy - 1)
if (Energy <= 0) [ die ]
if any? sharks-on patch-ahead 0 and Btimer <= 0
[ ask sharks-on patch-ahead 0
[ set Btimer (Btimer + 400 - random 200)
set Energy (Energy - 50)
]
hatch 10 [ ]
]
]
end
But this is primarily a design issue - what are you trying to represent with stopping the growth? Is it that the shark has become an adult, in which case a condition like the one I have inserted is the right approach.
Or is it that you expect growth to stop naturally for some other reason? For example, you might be thinking that the shark will stop growing because it runs out of food. However, the growth happens whether there is food or not. If you wanted the growth to happen only if there is food (fish) where the shark is, then you would do something like this:
to go
....
ask sharks with [any? fishes-here] ; restrict to sharks with food
[ set Btimer (Btimer - 1)
forward Energy / 7
right random 80
left random 80
ask fishes-here [ die ] ; since they are shark food
set Energy (Energy + 7) ; max not required, grows if food available
set size size + 0.1
]
....
end
Just a general comment, agent-based models are hard to debug because the complex interactions between agents, environment and behaviour means that it is not always clear which bit of the code is causing a problem, and the logic can be difficult. The best way to deal with this is to code in smaller pieces - just add the minimum change and make that work before writing anything else. For example, the way you have the code written, all fishes die immediately. That is a different problem. If you write only one piece at a time, then you only ever have one problem and you know what is causing it.
I am new to Netlogo and am progressing pretty well with programming. However, I am currently stuck on an issue.
I am using turtles as fish super-individuals (see Railsback and Grimm 2005) which means each turtle has arguments for abundance, sex, age and size. At the end of a year cycle, I would like to find turtles with the same characteristics of sex, age and size and then combine their abundances into one turtle of the same characteristics (then all will be die except the newly combined turtle). Does anyone know how to do this? Any advice would be greatly appreciated.
I didn't test my solution, but this should work. Essentially, for each turtle figure out who are the turtles with the same properties and add it to a running total of abundances, then ask them to die.
ask turtles [
let others-abundance 0 ;; accumulate other's abundances
ask other turtles with [ sex = [sex] of myself and abundance = [abundance] of myself and age = [age] of myself] and size = [size] of myself] ;;determine who are the others with same properties
[
set others-abundance other-abundance + abundance
die
]
set abundance abundance + other-abundance
]
I'm trying to build a simulation where commuters can choose to take the car or bike to work. I'm want the turtles to make a decision based on their wait time in traffic from the last 20 ticks e.g. if average wait time is more than 10, they will take the bike to work. I have a plot that shows average wait time of cars and managed to have them make decision on that overall average. However, I have not managed to make each car make a decision based on their own experience. I'm not getting any errors, just not any results.
So far I have turtles owning average-wait-time-list and wait-time.
Create-cars ;;(cars are one of two breeds)
set average-wait-time-list []
to-report average-wait-time-sum
;; drop the first member of the list, but not until there are at least 60 items in the list
if (length average-wait-time-list > 20) [ set average-wait-time-list but-first average-wait-time-
list ]
;; add the number of raindrops created in last tick to the end of the list
set average-wait-time-list lput wait-time average-wait-time-list
report sum average-wait-time-list
end
to record-data ;; turtle procedure
ifelse speed = 0 [
set num-cars-stopped num-cars-stopped + 1
set wait-time wait-time + 1
]
[ set wait-time 0 ]
end
I want to modell the interactions of different tree species in a forest. To do so, I also have to simulate the growth/spread of the forest.
There I face the two following problems:
I want the trees to reach a minimum age from which on they can hatch a new tree each year. But I only know how to make them reproduce every (e.g.) 20 years.
There is also a set age at which the trees are chopped town. The problem is, that when this age is reached, all trees of one breed are chopped down, even if their age should actually be less than their harvest-age.
Here are the relevant parts of my code:
to go
ask oaks [set age ticks]
end
to set-harvest-age
ask oaks [set harvest-age 240]
end
to spread
ask oaks [
if (age mod 30 = 0) and (count oaks > 1) [hatch-oaks 1 [setxy random-xcor random-ycor set age 1]]]
end
to chop-down
ask oaks [if (age >= harvest-age) [die]]
end
The "set age 1" in "spread" does not seem to work. Maybe someone of you has an idea.
Thank you!
I think your main problem is the process order here. Every time go is called, all oaks will set their age to the current ticks. That includes any new saplings that you've hatched, so even if their age was 1 when they hatched, those saplings would instantly be set to the same age as all other oaks (which is just the number of ticks. Instead, you should use your oaks-own (or whatever species you want) variable to track the age of each individual turtle by incrementing it every tick rather than setting it to the ticks.
Additionally, it's probably better to use go or a similarly named procedure to act as the scheduler to call all the other relevant procedures. For example, check out these setup chunks:
breed [ oaks oak ]
oaks-own [ age harvest-age ]
to setup
ca
spawn-oaks
reset-ticks
end
to spawn-oaks ; setup procedure
create-oaks 10 [
set shape "tree"
set color green
setxy random-xcor random-ycor
; Set the harvest age
set harvest-age 100
; Randomly choose the age of the first generation
; to be somewhere between 50 and 75
set age 50 + random 25
]
end
This creates 10 oaks with a an age randomly between 50 and 75. It also sets their harvest age. Now, use a procedure to increase every oak's individual age by one each tick:
to get-older ; Oak procedure
set age age + 1
end
Then, something to have them start creating saplings when they reach maturity. I've included an if any? other oaks-here qualifier so that the population size doesn't immediately explode (as saplings can only survive on a patch without an established oak), but you would limit that growth in whatever way makes sense for your model.
to spread ; Oak procedure
; Get living, mature oaks to spead saplings nearby
; only some years (to avoid population explosion)
if age > 30 and random 50 < 5 [
hatch 1 [
; set sapling age to zero, and have it
; move away from its parent randomly
set age 0
rt random 360
fd random 5
if any? other oaks-here [
die
]
]
]
end
Finally, your chop-down procedure should actually work without changing now that the age issue is sorted out:
to chop-down ; Oak procedure
if age >= harvest-age [
die
]
end
Now all that's needed is to use go to call those procedures in the correct order:
to go
; Use the go procedure to schedule subprocedures
ask oaks [
get-older
spread
chop-down
]
tick
end
Bit of a silly example but hopefully will get you pointed in the right direction!