I have a question about Netlogo.
Is there any smart way how to find block of patches (in my case, I need to find block of three patches with yellow color => more precisely, I need to find row or column with three yellow patches next to each other).
Is there any Netlogo function I could use or is it neccessary to use loops and work as I would with two-dimensional array?n
blckbird is correct, if you want you can extract all coordinates of yellow patches and process those coordinates to figure out which patches are adjacent.
If all you need is to know where your rows or columns of threes are, however, you could also get all the yellow patches to check the color of neighboring patches and tell you if a row or column is formed. For an example, see the code below.
to setup
ca
reset-ticks
ask n-of 150 patches [
set pcolor yellow
]
end
to find-threes
;; for rows
ask patches with [ pcolor = yellow ] [
if ( [pcolor] of patch-at 1 0 = yellow ) and ( [pcolor] of patch-at -1 0 = yellow ) [
;; do whatever you need
set pcolor pcolor - 3
show ("I am the center of a row of three")
]
]
;; for columns
ask patches with [ pcolor = yellow ] [
if ( [pcolor] of patch-at 0 1 = yellow ) and ( [pcolor] of patch-at 0 -1 = yellow ) [
;; do whatever you need
set pcolor pcolor - 3
show ("I am the center of a column of three")
]
]
end
With ask patches you can loop over all patches. Further a condition can be applied to the ask statement by using with. So you are looping over all the patches meeting that condition. Here I just put the x and y coordinates of the patches in a list which you can then further process.
let yellow_patches []
ask patches with [pcolor = yellow] [
set yellow_patches lput [pxcor pycor] yellow_patches
]
Related
I am working on an infectious disease model, I've created a world with two regions. The specified number of people get initialized in their specific region.
Now, I need to initially infect the same number of people in each region with the disease using the initially_infected global variable. e.g 10 people infected in one region and 10 in the other region.
The infection should be indicated by changing color of turtles to red.
I've tried using "n-of" but it is not working correctly as want to restrict the initially infected people in their respective regions.
to setup_agents
create-humans green_population [
move-to one-of patches with [pcolor = green and not any? humans-here]
set shape "green person"
set color yellow
set size 1
set green_antibodies 0
]
ask n-of initially_infected humans [set color red]
create-humans blue_population [
move-to one-of patches with [pcolor = blue and not any? humans-here]
set shape "blue person"
set color yellow
set size 1
set blue_antibodies 0
]
ask n-of initially_infected humans [set color red]
end
Your code is not working because you are asking humans in general (by using ask n-of initially_infected humans [set color red]), and not based on where they are.
You can tackle this in a variety of pretty much equivalent ways. To do it in the tidies way, you should ask yourself what is the main programming feature that univocally differentiates these two groups: their shape? the color of the patche they are on? should they hold a turtles-own variable differentiating them? should they be separate breeds?
Whatever you choose this feature to be, use that feature in the ask n-of ... statement.
In the fully-reproducible example below, I just use the turtles' color as the distinguishing element:
breed [humans human]
globals [
green_population
blue_population
initially_infected
]
humans-own [
green_antibodies
starting_region
]
to setup
clear-all
ask patches [
ifelse (pxcor > 0)
[set pcolor green]
[set pcolor blue]
]
set green_population 300
set blue_population 270
set initially_infected 10
setup_agents
end
to setup_agents
create-humans green_population [
move-to one-of patches with [(pcolor = green) AND (not any? humans-here)]
set color green + 1
]
create-humans blue_population [
move-to one-of patches with [(pcolor = blue) AND (not any? humans-here)]
set color blue + 1
]
ask n-of initially_infected humans with [color = green + 1] [
set color red
]
ask n-of initially_infected humans with [color = blue + 1] [
set color red
]
end
Perhaps a more elegant option would be to create a little procedure that takes the populations' color and the quantity to infect as inputs. Modifying only the relevant part of the code, it would be:
to setup_agents
create-humans green_population [
move-to one-of patches with [(pcolor = green) AND (not any? humans-here)]
set color green + 1
]
create-humans blue_population [
move-to one-of patches with [(pcolor = blue) AND (not any? humans-here)]
set color blue + 1
]
infect-humans (green + 1) initially_infected
infect-humans (blue + 1) initially_infected
end
to infect-humans [hue quantity]
ask n-of quantity humans with [color = hue] [
set color red
]
end
In my example I used the humans' colors as distinguishing factor, but you can easily adapt this to any other thing you might want to use.
I'm working on a smaller project and got stuck on an issue, I'm not really sure if it's possible to solve it in NetLogo but I want to give StackOverflow a go!
I got a model that divides the world into different parts and randomly add physical features (such as rivers). If a feature goes through the whole region, I want it to separate the region and make into two regions. As an example, in the picture below, I want to separate the purple region into two unique regions accordingly to the physical feature (black).
The code I used to generate the picture above, can be found below.
to setup
ca
;Setting world.
resize-world 0 19 0 19
;Creating regions.
let x 5
let y 5
let col 45
while [y <= max-pycor + 1][
while [x <= max-pxcor + 1 ][
ask patches with [pxcor < x and pxcor >= x - 5 and pycor < y and pycor >= y - 5][
set pcolor col
]
set x x + 5
set col col + 10
]
set x 5
set y y + 5
]
;Generating physical features.
ask n-of 5 patches[ sprout 1[
set pcolor black]
]
let i 0
while [ i < (max-pycor * 2 )][
ask turtles [
fd 1
set pcolor black
ifelse (random 20 <= 1)
[
rt one-of [-90 0 90]
forward 1
]
[
fd 1
set pcolor black
fd 1
set pcolor black
]
set pcolor black
set i i + 1]
]
ask turtles [die]
end
My strategy for handling this is to realize that all we really need to do is "flood" a patch out by color and tag all the found adjacent patches, then repeat for any un-tagged, non-black patches until they are all done.
NetLogo does not have a "flood" command to get all patches adjacent to a patch meeting a criteria, so we make a special reporter of our own to handle it, patches-adjacent. Then it's just easy to ask those patches-adjacent to set their region to the currently chosen region.
I don't love this code, it's a little finicky and would be prone to infinite loops if tweaked incorrectly, but it should work. I bet there is a cleaner way to do this that I'm not thinking of at the moment.
; add a variable to track the different regions
; the default value will be `0` for each patch when `clear-all` is called
patches-own [ region ]
to set-regions
let current-region 1
; only act on non-black patches that haven't yet been assigned a region
let untagged patches with [ region = 0 and pcolor != black ]
while [any? untagged] [
ask one-of untagged [
ask patches-adjacent [
set region current-region
]
]
; update the region and the untagged patches we have left to process
set current-region current-region + 1
set untagged patches with [ region = 0 and pcolor != black ]
]
; this is just to get a view of the regions to quickly see if our code worked, it can be removed
ask patches [ set plabel region ]
end
to-report patches-adjacent
report patches-adjacent-ex (patch-set self) pcolor
end
to-report patches-adjacent-ex [found pc]
let newly-found neighbors4 with [ (not member? self found) and pcolor = pc and region = 0 and pcolor != black ]
set found (patch-set found newly-found)
ask newly-found [
; use recursion to find the patches adjacent to each newly-found one
; relying on updating the `found` agentset as we go to avoid duplicates
; or looping forwarder
set found (patches-adjacent-ex found pc)
]
report found
end
I solved this by using the Patch Clusters model that can be found in the NetLogo model library.
I have patches as follows:
I would like to color white patches as in this figure:
Here my code to color white patches in blue:
ask patches with [pcolor = white] [
if any? neighbors with [pcolor = blue] [set pcolor blue] ]
But the problem is that I obtain this figure: .
Thanks in advance for your help.
Alan is right about the cause of your problem, but you don't need to create a next-pcolor patch variable. If you put both conditions inside the with block, NetLogo will first construct the agentset of patches, and then ask these patches to do stuff, thereby avoiding the timing problem that you had. Let's try it. And since you're obviously going to have to do it with both blue and cyan patches, let's build a more general version:
to color-white-patches-v1 [ c ]
ask patches with [ pcolor = white and any? neighbors with [ pcolor = c ]] [
set pcolor c
]
end
That you can then call with:
color-white-patches-v1 cyan
color-white-patches-v1 blue
Here is the result:
But it's not quite what you wanted. That's because neighbors gives you all 8 neighbors of a patch. Let's try with neighbors4 instead:
to color-white-patches-v2 [ c ]
ask patches with [ pcolor = white and any? neighbors4 with [ pcolor = c ]] [
set pcolor c
]
end
Not quite there yet. It think you are going to have to resort to something like patch-at. In this example, I look at only the patch above:
to color-white-patches-v3 [ c ]
ask patches with [ pcolor = white and [ pcolor ] of patch-at 0 1 = c ] [
set pcolor c
]
end
I'm not sure if that was exactly what you wanted and how well that applies to your general problem, but with some combination of patch-at, you should be able to get what you need.
The problem arises because patches are being changed sequentially, so some white patches find they have new blue neighbors by the time they respond to ask.
ask patches with [pcolor = white and any? neighbors with [pcolor = blue]] [set pcolor blue]
Note: this answer is edited in response to Nicholas's observation that with will create the entire agent set before ask is called. However I stuck with neighbors since that's how I read the question.
I want to place turtles on each of the black patches(below Figure) such that there is no gap between turtles at all:
Code I use right now:
ask patches with [pcolor = black][sprout-dead-turtles wall-agents [set color red]]
This gives the following result:
But I want to place turtles in between each of the two patches as well. So that I can cover the showing black part.
Note: Changing the shape of turtles is no use to my purpose though it would cover the black area. My aim to create a replusion force field from these agents and gaps in between are loop holes from where agents may escape.[Somewhat similar to agents bouncing back on a wall].
Here is a fun solution:
breed [ dead-turtles dead-turtle ]
to setup
ca
; draw the background:
ask patches with [ abs pxcor != max-pxcor and abs pycor != max-pycor ] [ set pcolor grey ]
ask patches with [ pycor = max-pycor and abs pxcor <= 1 ] [ set pcolor white ]
set-default-shape dead-turtles "circle"
; sprout a first set of turtles:
ask patches with [ pcolor = black ] [
sprout-dead-turtles 1 [ set color red ]
]
; create temporary links between these, and use the
; links to place a new set of turtles in between:
ask dead-turtles [
create-links-with turtles-on neighbors4
]
ask links [
let target end2
ask end1 [
hatch 1 [
face target
fd distance target / 2
]
]
die ; remove the link
]
end
I'm not saying that it is the only possible solution, but it's simple enough, and it works. (World wrapping has to be turned off, though, which I assume is the case.)
I'm making a maze on netlogo and I want to do it so that once it tries to walk into the violet lines, it'll stay on its own patch instead of moving forward. What command would that be? I tried bk 1 to reverse the fd 1 but it doesn't work all the time
You can undo your step like this:
ask turtles [
fd 1
if pcolor = violet [fd -1]
]
Or you can check ahead of time as Marzy answered. Basically it's the difference of asking for forgiveness vs permission :-)
I hope this example answer your questions:
turtles-own [target]
to setup
clear-all
reset-ticks
ask n-of 100 patches [
set pcolor red
]
create-turtles 1
[ move-to one-of patches with [pcolor != red]
set heading 90
set target one-of patches with [pcolor != red]
ask target
[
set pcolor green
]
]
end
to go
ask turtles
[ifelse pcolor != green
[
ifelse [pcolor] of patch-ahead 1 != red
[
Your-Move-Function
]
[
Your-Bounce-Function
]
leave-a-trail
]
[stop
print ticks
]
]
tick
end
to Your-Move-Function
let t target
face min-one-of all-possible-moves [distance t]
fd 1
end
to Your-Bounce-Function
let t target
face min-one-of all-possible-moves [distance t]
end
to-report all-possible-moves
report patches in-radius 1 with [pcolor != red and distance myself <= 1 and distance myself > 0 and plabel = "" ]
end
to leave-a-trail
ask patch-here [set plabel ticks]
end
This is how it works:
Random patches are colored Red to show walls or obstacles, one turtle is created in a random location with a random target which is colored green:
I have used a variable to store all available patches which turtle can step on , but since I have considered a target for the turtle, turtle chooses the one patch which is closest to the target, and since I have noticed in some cases it might go in circle I have asked the turtle to leave tick number which is its move number as a plabel, you can use a variable for that for specifying if that path was already selected or not.