Is there a way to ask up to a certain number of patches? For example, ask up to 100 patches but there are only 50 available, so the action takes on this 50 patches. Thanks.
The way to do this at the moment would be something like:
to-report at-most [n agents]
report ifelse-value (n <= count agents) [ agents ] [ n-of n agents ]
end
You can then say ask at-most 100 patches [ ... ] and you will get what you want.
Note that this doesn't work if there is a chance that your variable contains nobody instead of an agentset. In that case, you can convert nobody to an agentset using patch-set, turtle-set or link-set, depending on the type of agent you expect it to contain. For example:
ask one-of turtle-set other turtles-here [ ... ]
Note that the need to jump through all these hoops might disappear in the near future. There is currently an open proposal to add a primitive to NetLogo for handling these cases: https://github.com/NetLogo/NetLogo/issues/1594.
Related
Picture of my behaviourspace menu
I'm working on an agent based model where a variable (agentvariable1) owned by all agents changes every tick. I want to report a time series for the values of this variable for every agent using Behaviourspace.
However, when I measure runs using the following reporter
[agentvariable1] of turtles
the values that are reported for agentvariable1 are randomly shuffled, because "turtles" calls all turtles in a random order, which is different every tick. Because of this the data that is exported is not usable to create a time-series.
Is it posstible to create a reporter in Behaviourspace that reports the values of the agentvariable1 in a sequence that remains the same every tick?
Using sort on an agentset creates a list of those agents sorting them by some criteria. In the case of turtles, they are sorted by their who which means that their relative order will always be the same.
However you cannot directly do [agentvariable1] of sort turtles, because of expects an agent/agentset but you are giving it a list.
What you can do is creating a global variable as a list: at each tick the list is emptied, and later all turtles (sorted as per sort) will append their value to the list.
That list is what you will report in your Behavior Space.
globals [
all-values
]
turtles-own [
my-value
]
to setup
clear-all
reset-ticks
create-turtles 5
end
to go
set all-values (list)
ask turtles [
set my-value random 10
]
foreach sort turtles [
t ->
ask t [
set all-values lput my-value all-values
]
]
show all-values
tick
end
As an alternative to Matteo's answer (which is perfectly suitable and directly addresses your intention, I just present another option depending on preference) you could also pair the variable of interest with some turtle identifier and report that as a list of lists. This adds a bit of flexibility in cases where the number of turtles increases or decreases. In this example, I use who and xcor for simplicity, but you may want to create your own unique turtle identifier for more explicit tracking. With this toy model:
to setup
ca
crt 5
reset-ticks
end
to go
ask turtles [
rt random 30 - 15
fd 1
]
tick
end
to-report report-who-x
report list who xcor
end
At any point, you can call the list with [report-who-x] of turtles to get a list of lists. With a behaviorspace setup such as:
you get an output that would look something like:
I want to write in Netlogo that a certain percentage of the agent's population has this attribute. How do I do that in NetLogo?
So far, in a toy model, I do it manually. i.e: ask n-of 740 households [set composition 1] when in fact I want to say: ask 8% of the households to set composition 1.
There are two ways. I will call them ex-ante and ex-post.
Ex-ante
A frequent approach is to let each agent have a certain chance (expressed as the percentage value) of doing something. In this case you will use the random-float command in combination with your percentage value, which is the standard way to make things happen in NetLogo according to a certain probability (see here, or also see just random if you're working with integers). It can be used directly within the create-turtles block of commands:
globals [
the-percentage
]
turtles-own [
my-attribute
]
to setup
clear-all
set the-percentage 0.083 ; In this example we set the percentage to be 8.3%.
create-turtles 500 [
if (random-float 1 < the-percentage) [
set attribute 1
]
]
end
This means that you will not always have the exact number of turtles having that attribute. If you check count turtles with [attribute = 1] on multiple iterations, you will see that the number varies. This approach is good if you want to reproduce the probability of something happening (over a population of agents or over time), which is the case for many uses of NetLogo models.
Ex-post
The ex-post approach follows the logic that you more or less expressed: first you create a number of turtles, later you assign to them the attribute. In this case, you simply need to treat the percentage as in any other mathematical expression: multiply it by the total number of turtles to get the relevant turtles:
globals [
the-percentage
]
turtles-own [
my-attribute
]
to setup
clear-all
set the-percentage 0.083
create-turtles 500
ask n-of (count turtles * the-percentage) turtles [
set attribute 1
]
end
With this approach, you will always have the exact same number of turtles with that attribute. In fact, if you run count turtles with [attribute = 1] on multiple iterations you'll see that the result is always 41 (500 * 0.083 = 41.5, in fact if the number passed to n-of is fractional, it will be rounded down).
I would like to apply some process stochastically, but the order matters, or rather it should be done at random, how can I select a set of the same turtles to "treat" but to do it such that each tick, the order is random?
ask turtles [
;; apply a process to turtles, but not all turtles will get something as the pool of energy may have run out by the time they are selected.
]
Elements of agentsets (such as turtles) are always returned in a random order. Each time you use ask with an agentset, it will ask them in a new, random order. From the docs on agentsets:
An agentset is not in any particular order. In fact, it’s always in a random order. And every time you use it, the agentset is in a different random order. This helps you keep your model from treating any particular turtles, patches or links differently from any others (unless you want them to be). Since the order is random every time, no one agent always gets to go first.
And here is a quick example to demonstrate. If you run it in the Command Center you'll see the who numbers will be different each time you ask them to be shown.
to test
clear-all
create-turtles 10
show "Asking once..."
ask turtles [ show who ]
show "Asking a second time..."
ask turtles [ show who ]
end
And here is an example showing an energy pool that will be randomly used until it is gone. Note the turtles that will get to use it are whichever happen to come first out of the agentset for ask:
to test-pool
clear-all
let energy-pool 1000
create-turtles 100
ask turtles [
; can only act if some energy is left...
ifelse energy-pool > 0 [
let energy-use (min (list random 100 energy-pool))
set energy-pool (energy-pool - energy-use)
show (word "I used up " energy-use " energy points! " who " Only " energy-pool " points left")
] [
show (word "No energy left for me! " who)
]
]
end
I am trying to create a code that will allow me to get the who numbers of 10 turtles and store them in a list. However, the "who" number can only be added to the list if it has not been added to the list before.
I have to use the "foreach" command to check if the number has already been added to the list.
Any suggestions on how to do so?
My code:
turtles-own [contact-list]
to setup
clear-all
create-turtles 10 [
set contact-list []
print who
]
reset-ticks
end
to go
ask turtles [
set contact-list lput [who] of one-of other turtles-here contact-list
foreach contact-list[
; this is where the command goes
]
print contact-list
]
end
Might it be easier to add all the who numbers to the list and then use the remove-duplicates primitive to remove the duplicate numbers? I assume that you have a reason for putting who numbers into the list rather than having a list of the agents themselves, or an agentset. In general, who numbers are to be avoided.
I am having trouble with summing lists of all turtles and am not sure where I am going wrong.
For instance, in the following code I would like to show the total number of apples among all the turtles. Every time I run the code I get a value of 0, when it should in theory be 100. I am not sure what the error is. Any assistance would be much appreciated!
turtles-own [ apples ]
to test
clear-all
create-turtles 5 [
set apples []
set apples lput 20 apples
]
show sum [apples] of turtles
end
The following code and test should sum all the numbers in all the turtles' lists.
turtles-own [ apples ]
to test
clear-all
create-turtles 5 [
set apples []
set apples lput 20 apples
set apples lput 10 apples
]
ask one-of turtles [set apples lput 30 apples]
show sum map sum [apples] of turtles ; here's the key command
end
map sum [apples] of turtles sums the number in each turtle's list and puts those sums in a list, and then the first sum adds them all up. I made one turtle's list longer than the others' just to be sure that all the lists do not need to be the same length.
Hope this helps,
Charles