I have a simulation in netlogo in which there is a setup for turtles all around the world.
The thing is when I create turtles, the go into random places.
How can I make them fix ?
note that I cannot specify xcor and yxor for every turtle as I have hundreds of them.
To setup-people
tick
set-default-shape people "person"
ask n-of 185 (patches with [pcolor = black]) [sprout-people 1]
ask people[ set color cyan ]
ask people [ set points 2 ]
reset-ticks
end
One way to do this is with the with-local-randomness command.
breed [ people person ]
people-own [ points ]
To setup-people
clear-all
set-default-shape people "person"
with-local-randomness [
random-seed 0
ask n-of 185 (patches with [pcolor = black]) [sprout-people 1]
]
ask people [ set color cyan ]
ask people [ set points 2 ]
reset-ticks
end
If you don't have a clear idea of what's happening here, I would strongly suggest reading the section on random numbers in the NetLogo programming guide.
The basic idea is that NetLogo will always use the same sequence of random numbers within the little block of local randomness, but it won't affect the rest of your model, so if you have other random behaviours, they will still vary from run to run.
That being said, how important is it that your people are always placed in the same location? Agent-based models usually have lots of random elements. If that makes you uncomfortable, it might be because you haven't fully taken stock of that yet. Just something to keep at the back of your mind as you move forward with your model design...
Note: I've replaced tick with clear-all at the top of your procedure, as I believe this is probably what you meant to write.
Related
I'd like to have patches count the number of turtles that have stood on them. What would be ideal is a event such as:
if turtle-lands-on-me [add one to count]
because a turtles could leave and come back and be counted twice (which is what I want) and it would avoid counting turtles who stand still twice or more (which I don't want). Is there any way to achieve this?
Thank you!
What you need is a variable for each patch (I am calling it 'landed' below). The following code assumes you want to know about the patch it lands on each time step, but ignores the ones it passes over. It also updates the counts only where the turtle changes the patch, as requested, and labels the patch with the count.
patches-own [landed]
to setup
create-turtles 20
[ setxy random-xcor random-ycor
]
end
to go
ask turtles
[ let old-patch patch-here
set heading random 360
forward one-of [0 0.5 1 3]
if old-patch != patch-here
[ ask patch-here
[ set landed landed + 1
]
]
]
ask patches [set plabel landed]
end
The problem is that a turtle can pass over multiple patches during one time step. You can see this in the example model for those turtles that move 3. If you also want them, you will need to do something like the 'Line of Sight' model in the NetLogo models library.
I am trying to create a network that moves through the environment as a "static" unit, i.e. nothing in the simulation changes except the position and orientation of the whole, the position and orientation of the individual turtles relative to one another are fixed by their links. Turtles are connected via undirected links, which are tied and set to tie-mode "fixed".
The problem is that in certain situations the links fail to remain fixed and link-lengths begin to change. Initially I noticed that, where the average network degree is relatively low or the network is a complete graph, the tie primitive works. However, when links were created to produce a graph that is moderately connected the link-lengths between the turtles begins to change. Upon further experimentation I can create a network with the same number of links and turtles but with different configurations i.e. the network structure is different, that sometimes maintain the positions and link-lengths but in other situations fail to do so.
How do I get the network to move as a unit no matter how connected the network is or what the configuration of the network is? See example code below, I have added code at the end where you can run multiple configurations of a network with 6 turtles and 6 links to see the issue for yourself, try running at least a half dozen iterations. Thanks!
this produces a network that moves as a unit
to setup
create-turtles 10
ask turtles [fd 2]
ask turtles [create-links-with other turtles [tie] ]
ask links [set tie-mode "fixed"]
reset-ticks
create-turtles 10
ask turtles [fd 2]
ask turtles [create-links-with other turtles [tie] ]
ask links [set tie-mode "fixed"]
reset-ticks
end
to go
ask turtles [lt 1 fd 1]
end
This produces a network whose links are still tied and set to tie-mode "fixed", but change their link-lengths. The more links that are asked to die, the more the link-lengths change.
to setup
clear-all
create-turtles 10
ask turtles [fd 2]
ask turtles [create-links-with other turtles [tie] ]
ask links [set tie-mode "fixed"]
ask one-of links [die]
reset-ticks
end
to go
ask turtles [lt 1 fd 1]
end
Here is additional code showing a specific instance of link-length change. Please input the seed 659269695 when prompted by the button "use-seed-from-user". Apologies if the code is clunky, first time using random-seed. "Print-lengths" button is to confirm that lengths change.
;USE seed: 659269695
to use-new-seed
let my-seed new-seed ;; generate a new seed
output-print word "Generated seed: " my-seed ;; print it out
random-seed my-seed ;; use the new seed
reset-ticks
end
;; Use a seed entered by the user
to use-seed-from-user
loop [
let my-seed user-input "Enter a random seed (an integer):"
carefully [ set my-seed read-from-string my-seed ] [ ]
ifelse is-number? my-seed and round my-seed = my-seed [
random-seed my-seed ;; use the new seed
output-print word "User-entered seed: " my-seed ;; print it out
reset-ticks
stop
] [
user-message "Please enter an integer."
]
]
end
to setup
clear-all
create-turtles 6
ask turtles [
fd 5
set shape "circle"
set size 1
set color yellow
if count links < 7 [ask one-of turtles [create-link-with one-of other turtles
[tie]]]]
reset-ticks
end
to go
ask turtles [lt 1 fd 1]
end
to print-lengths
print sort-by < [precision link-length 2] of links
end
I slightly revised your code so that the go procedure includes breaking a link. I also got rid of the explicit setting of tie-mode since that is done by setting the link to tie and added a tick so I could plot. So the code looks like this:
to setup
clear-all
create-turtles 10 [fd 2]
ask turtles [create-links-with other turtles [tie] ]
reset-ticks
end
to go
ask one-of links [die]
ask turtles [lt 1 fd 1]
tick
end
As far as I can see, the turtles move as a unit until it fragments with the loss of links.
I added a monitor for mean [link-length] of links, which is what I think you are asking about and also a plot of the same calculation. Yes, it is true that the average link length changes, but remember that the links are not all the same length. If a longer one dies, then the average length will reduce, and if a shorter one dies then the average will increase. The plot wanders a little, but it is basically flat until fragmentation.
I have set up agents and nodes to represent people and stores and it is my intention that the agents will "target" the store in their "awareness" space with the highest value ("vulnerability"). I've largely coded what I have so far through trial and error however setting the turtle's target to the patch with the highest value within a 10 unit radius is a hurdle I can't get over. Currently they target the patch with the highest value regardless of its position in the world. Could somebody suggest what I might consider to achieve this please? I have pasted what I have written so far for reference.
Thanks.
breed [shoplifters a-shoplifter]
patches-own [vulnerability]
shoplifters-own [target
awareness]
to setup
clear-all
setup-patches
setup-turtles
reset-ticks
end
to setup-patches
setup-stores
end
to setup-stores
ask n-of num-stores patches [ set pcolor lime ] ;; create 'num-stores' randomly
ask patches [
if pcolor = lime
[ set vulnerability random 100
]
]
end
to setup-turtles
setup-shoplifters
setup-target
end
to setup-shoplifters
create-shoplifters num-shoplifters [ ;; create 'num-turtles' shoplifters randomly
set xcor random-xcor
set ycor random-ycor
set shape "person"
set color red
]
end
to setup-awareness
ask turtles [
set awareness
patches in-radius 10
]
end
to setup-target
ask turtles [
set target
max-one-of patches [vulnerability]
]
end
You are on the right track using max-one-of. At the moment, however, you are sending patches as the space to search through to look for the one with maximum vulnerability value, when you really want patches in-radius 10. So you could simply do this:
to setup-target
ask turtles [
set target max-one-of patches in-radius 10 [vulnerability]
]
end
However, this is going to be inefficient because NetLogo will have to first work out which are the patches within the radius. You have already asked the turtles to work this out and assign it to their variable 'awareness'. What you really want to do is therefore:
to setup-target
ask shoplifters [
set target max-one-of patches awareness [vulnerability]
]
end
Note that I also changed ask turtles to ask shoplifters. It is only shoplifters who have the attribute 'target' so you should only be asking them to calculate it. Same thing goes for 'awareness'. At the moment you don't have any other breeds so it's not causing an error, but it is good practice to use the breed, otherwise there is no point in creating it.
I've made a animal behavior model involving "turtles" and "roads" and I want the model to report back to me when the turtle "crosses" a road. All I want is that it tells me when the turtle moves from a patch that is the grey color to the red color. I've included the code asking it to report this and the program has no issue with the code. To give me a visual representation of what I want it to report, I put a monitor on interface. But it always gives me a "0" for road crossings, even as I can see that my turtle has crossed roads. I would count it by hand, but it's impossible to tell for certain how many road crossings there are and this is for scientific publication. My code is as follows...
turtles-own [
road-crossings
]
to setup
clear-all
;; create turtles on random patches.
ask patch 6 -15 [
sprout 1 [
set color one-of [green]
set size 1
set road-crossings 0
]
]
ask turtles [
if [pcolor] of patch-here = 14.9 [
set road-crossings road-crossings + 1
]
]
reset-ticks
end
to go
ask turtles [
repeat 100 [
repeat 39 [
pen-down
rt random-float 360
lt random-float 360
fd random-float 1.375
]
setxy 6 -15
]
]
tick
end
Any help is appreciated! Thank you!
There are several potential problems with this that I can see.
First, road-crossings is a turtle variable, which is the correct thing to do if you want each turtle to remember how many times it crosses a road. If so, however, the monitor must report sum [road-crossings] of turtles to get the road crossings of all turtles.
Second, which I think is actually your problem: you have the turtle checking whether it crosses the road in the setup procedure rather than the go procedure. The setup procedure is only run at the beginning.
Third, you don't actually have any roads in your example code, but I suspect that's just a failure to create a proper example. I assume that there are patches with pcolor of 14.9 in your real code. If not, though, that would also cause your error. You can make sure by going into the command center and asking count patches with [pcolor = 14.9]
We try to show a simple infection via Netlogo. For our purpose we need to start the infection with the same turtle for several times.
But right now with every setup another turtle begins with the infection. We already tried to work with the Node ID, but unfortunately the ID of the different turtles changes with every setup, too. We are out of ideas but
maybe there is a way to sove this problem I am happy for any answers :)
This is our Code so far:
extensions [nw]
globals
[
num-informed
informed-size
]
turtles-own
[
informed?
]
to setup
clear-all
nw:load-graphml "JK_nachnamen.graphml"
ask turtles [ set size 1.5 ]
layout-radial turtles links turtle 61
ask turtles [set color red]
ask turtles [set shape "dot"]
ask links [set color grey + 1.5]
ask patches [set pcolor white]
ask turtles [set label-color black]
ask turtles [set informed? false]
ask turtle 72
[
set informed? true
set color green
]
set num-informed 1
set informed-size 2
reset-ticks
nw:save-graphml "JKnachnamennetlogo.graphml"
end
to spread
if (count turtles with [informed? = true] > .7 * count turtles) [stop]
ask turtles with [ informed? = true ]
[
ask link-neighbors with [not informed?]
[
if (random-float 1 <= 0.01)
[
set informed? true
show-turtle
set color green
]
]
]
set num-informed count turtles with [informed? = true]
tick
end
Thank you a lot.
I am a little unclear so am giving bits of different answers for different situations.
If the turtles are different each time, what do you mean by 'the same turtle'. For example, do you mean the turtle in a particular position? If so, you could select the turtle on the appropriate patch.
If it doesn't matter which particular turtle it is (just that it's the same turtle), then the simplest approach is to set the random-seed. Then every time you run any random process (including choosing one-of the turtles to select the starting infection, or ask turtles to do something), NetLogo will use the same chain of random numbers. Of course, if you are still building your model, then adding new pieces of code that change how many calls are made to the random number generator will lead to a different chain, but rerunning with the same code will give the identical run.
You may need to use with-local-randomness and random-seed new-seed if you want to have some parts actually change.
The problem is that nw does not store the WHO variable this is to avoid conflict with already existing turtles in a model.
A work-around would be assigning each turtle a separate id variable and setting that to who.
turtles-own [informed? id]
in turtles creation asign them each the id thus
set id who
you may want to write a conversion procedure like this
to convert
nw:load-graphml "JK_nachnamen.graphml"
ask turtles [set id who]
nw:save-graphml file-name "JK_nachnamen(id).graphml"
end
and use the copy. Of course you would not use
turtle 74
but
one-of turtles with [id = 74]