I want to add the values of a variable ( let's say transportation cost) for specific turtles which are in a group. The transportation cost depends on the distance between a specific patch and the location assigned to the turtle. As the value of the said cost is different for each turtle, I want to sum the total cost for turtle which are in a group. To clarify, let's suppose there are 7 turtles in total and only 4 are in a group.
The values of transportation cost of each turtle is assigned as tcost.
to calculate-ttcost
set ttcost 0
let cnt 0
ask turtles [
if in-group? [
set ttcost (tcost + tcost)
set cnt cnt + 1
]
]
end
With the correction of one typo, the code you have should work, assuming that tcost is declared as a turtles-own variable with that turtle's transportation cost (or a reporter that gives the transportation cost for the turtle that calls it), and assuming that those turtles that are in the group in which you are interested have their turtles-own variable in-group? set to true. The typo is in the line
set ttcost (tcost + tcost)
which should be
set ttcost (ttcost + tcost)
But there is a more straight-forward coding that will accomplish the same task.
let cnt count turtles with [in-group?]
let ttcost sum [tcost] of turtles with [in-group?]
with limits the set of turtles to those for which in-group is true. of creates a list of the values of tcost for each of those turtles, which can then be summed up.
Related
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'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've got a doozy of a Netlogo question. If I have two different breeds of turtles, can the sum of a specified number of one breed's variables BE THE VARIABLE of the other breed?
Here is my train of thought. I’d like to model water usage of multiple households, but that water usage of a household needs to be dependent on a) the fixed values of the house (like water used by a faucet) * b) frequency of use of faucet by a person. With each household containing either 1 or more person (people) and that frequency of use can vary person to person.
The idea of using two turtle breeds would allow me to see how the decisions made by one breed affects the other.
Here is my pseudo code to help illustrate what I was thinking (not intended to be a working code)
globals []
breed [People person]
breed [Community household]
People-own [frequency]
Community-own [waterusefacuet HouseholdWaterUse]
;; =================================================================================================================
;; =================================================================================================================
to setup
clear-all
HouseholdCreation
PersonCreation
reset-ticks
end
to go
ask Community [WaterConsumption]
tick
end
;; =================================================================================================================
;; =================================================================================================================
to HouseholdCreation
ask patches [ sprout-Community n of 1 [
set size 1.0 set shape "square" set color blue
set waterusefacuet (1)
] ]
end
to PersonCreation
ask Community [ hatch-People 1 [
set size 0.5 set shape "circle" set color red
set frequency (1 + random 4)
]]
end
to WaterConsumption
Set HouseholdWaterUse (waterusefacuet * (frequency * # of people) )
end
Why not simply make each patch a household, have each patch have one or more turtles (persons), and then calculate household factors as patch factors? To define communities one could place patches into zones (e.g., if pxcor >= 5 and pxcor <=8 and pycor >=3 and pycor <= 6 set zone 1) <== not meant to be code, just the idea.
You could set patch size to make each patch small and specify a large zone of patches.
can the sum of a specified number of one breed's variables BE THE VARIABLE of the other breed?
Absolutely.
snipsnip for clarification : In my code here, I do not let the water use of people who live in a household BE the water use variable of that household. And generally I would recommend against a solution that lets the state of one (or more) agents be the state of another variable - unless there is a very good reason for it. Having states depend on each other is dangerous because you always have to make sure that you sync the values between agents. More importantly, it's often unnecessary. In my solution here, each person belongs to a household, and when that households calculates its total water use, it asks all its inhabitants to send them their use on that day, and then returns the sum of all those numbers. I hope that makes sense. If not, please do ask.
*< /snipsnip>
You need to use the of keyword though. of allows you direct access to variables from the context/perspective of one or more individual agent. So, let's say we have households and people, and people (because we all have different water use habits) have some frequency of water tap uses. In fact, we could have people draw the amount of water they use every day from a a normal distribution that is unique to them. Let's do that:
breed [people person]
breed [households household]
people-own [
mean-use-per-day ;; mean use per day
sd-use-per-day ;; standard dev per day
my-household ;; the household to which a person belongs
]
to setup
create-households 10 [
hatch-people random 4 + 1 [ ;; between 1 and 4 people in a household
set mean-use-per-day random 5 + 5 ;; mean 5-9
set sd-use-per-day random-float 3 ;; sd 0.00-2.99
set my-household myself ;; we set the person's household to the household that hatched them
]
]
to-report household-water-use ;; household reporter
report sum [random-normal mean-use-per-day sd-use-per-day] of people with [my-household = myself] ;; this creates a list of water uses based on the random use of each person in the household.
end
in order to run this code, you can simply call
show [household-water-use] of households
from the command center. This will give you a list of the water use of each household. Or if you want to just see the water use of one household on one random day, you can try
show [household-water-use] of one-of households
Is there a way to store / recall values of a variable in Netlogo from previous ticks?
I need a way to recall what a variable was from previous ticks. If my turtle variable R was equal to 0 the last 3 ticks, I need it to set another variable back to zero.
Here is what that I was thinking.
to regression
ask turtles [if (R = 0 from last 3 ticks [Set Oin 0 ]]
end
How about making a list of variables, then limiting the length of that list to how far back you'd like the agent to "remember"
set memory []
then add to the list each tick and get rid of old memories with
set memory lput value memory
if length memory >= 4 [set memory but-first memory]
and if zero is on the list, have that alter behavior in some way
if member? 0 memory [blah]
The deal is this:
I have three types of turtles.
Every type of turtles contain three turtles
Each turtle has three variable with its own value
How could i ask netlogo to get the average value of each group of turtles
I think you mean something like
let type1-average-x mean [x] of turtles with [type = "1"]
You'll want to do this for each type and for each variable that you'd like the measure of.