I am trying to count the number of "buyer" type turtles, which have a certain surplus (turtle variable) greater than or equal to zero, and price (another turtle variable) greater than the current turtle's price (already grabbed in local variable myprice...although there may be a more direct way to put it in)
let countup count buyers with ([surplus >= 0] and [price > myprice])
NetLogo returns
Expected a TRUE/FALSE here, rather than a list or block.
let countup count buyers with (surplus >= 0 and price > myprice) returns
WITH expected this input to be a TRUE/FALSE block, but got a TRUE/FALSE instead
Close! You're looking for:
let countput count buyers with [ surplus >= 0 and price > myprice ]
with is a report that takes two arguments, like so
<turtleset> with <report block>
where the reporter block is a clump of code surrounded by [ ] that will result in either true or false. In general [ ] is netlogo's way of grouping together code so you can doing something special with it, such as having each agent in an agentset run it. Hope that helps!
Also, I assume you've got something like let myprice price on, say, the line above this one. You can combine those lines like so (not saying this code is the right way to do it, just wanted to show another option):
let countput count buyers with [ surplus >= 0 and price > [ price ] of myself ]
Checkout the docs for (the very poorly named) myself.
Related
I am trying to write a procedure where a turtle of a certain breed asks turtles of the same breed, within a certain distance, the value of a certain variable. The asking turtle will then capture the values add them to it's own, map + them and then reduce + to a single number. Here's the code
ask Teams
[ if AsgnE = "E 1"
[
ask Teams with [ distance myself < 25]
[
; assuming that there are no more then 2 teams within distance
let Val1 []
let Val2 []
let Val3 []
set Val1 Value
set Val2 Value
set Val3 [Value] of self
let Val4 (map + Val1 Val2 Val3)
set Val4 (reduce + Val4)
set Storys1 [Stories] of Epic 0
if Storys1 > 0 [ set TotValue1 Val4 ]
]
]
]
The values of each Team continuously update as long as the go button is pressed. The issue is that the resulting number never matches the aggregate of all the values. As the number updates they never match the totals of the separate Teams. Sometimes the number drops to a lower number (I'm assuming it's representing a single teams value) before jumping back to a higher number.
Any idea on how to fix this?
Thanks
Rudy
My guess is that it's a synchronicity problem. The ask will iterate (in random order) through all the turtles. Let's say it starts with turtle 1 - so turtle 1 updates its value to be the sum of its old value and all the values of the nearby turtles. Then the ask moves on to turtle 2, and turtle 2 happens to be nearby to turtle 1. That means turtle 2 adds all the numbers again, with turtle 1 having its adjusted value. With just these two turtles, the value for turtle 2 gets added in twice because turtle 1 also has it hidden in its new value.
If this is not the behaviour you want, the easiest thing to do is to have an extra variable called something like next-value. Calculate next-value for each turtle as the appropriate sum. Then, in a new ask, get each turtle to set value next-value to update them all at the same time.
Also, your map and reduce seems unnecessarily complicated. If what you are trying to achieve is to add the value of a variable over a bunch of turtles, then you can simply do a sum of the variable after constructing the relevant turtle agentset. But it may be that you simplified for the purposes of the question, in which case just ignore this!
UPDATE ---- added complete model example
turtles-own
[ team
myval
nextval
]
to setup
clear-all
create-turtles 20
[ setxy random-xcor random-ycor
set team one-of ["A" "B"]
set myval 1
]
reset-ticks
end
to go
ask turtles
[ let myteam turtles with [team = [team] of myself]
set nextval sum [myval] of myteam
]
type "total before: " print sum [myval] of turtles
ask turtles
[ set myval nextval
]
type "total after: " print sum [myval] of turtles
end
I would like to make the sum = the total of pollen recieved by a plant from other plants (Donnors) which is stored in a list of a list (own by each turtle = plant).
The following code make an error (when computing the sum):
OF expected input to be an agent or agentset but got the list
[[119.05593 50 50] [301.25853 50 50] [30.23906 50 50] [460.525845 50
50] [55.16717 50 50] [301.25853 50 50]] instead.
Does any one could help me about the mistake in the line "set Tot_pol sum ..." ?
Many thanks for your help.
to check-pol [m] ;; we check the pollen recieved by the two morphs
set Donnors [] ;; empty list of pollen donnors
ask zsps with [morph = m] ;; morph of the pollen reciever
[
set totpol 0
;; check for pollen donnors and morph for compatiblity within a radius :
ask zsps with[distance myself <= 20 and morph != m]
[
set totpol (NMaleFlowers * 100 * item round (distance myself) pollination-list) ;; the farther the less pollen
set Donnors lput [ (list totpol NMaleFlowers NFemFlowers)] of myself Donnors
]
set Tot_pol sum [ item (position 0 Donnors) Donnors ] of Donnors ;; total of pollen recieved
]
end
Luke's answer is good and should fix your problem. I suspect, however, that you are going to be doing lots of these types of sums. You may wish to set up a to-report that you can use for whichever item you want to sum over, just by passing the item number and the name of the list of lists. It would look like this:
to-report sum-item [#pos #listoflists ]
let items map [ x -> item #pos x ] #listoflists
report reduce [ [a b] -> a + b] items
end
The first line extracts the relevant item (remember index from 0) into a new list which the second line sums.
You would then use it with set Tot_pol sum-item 0 Donnors
Here's an answer that is not actually responding to your question. Instead, it is a more NetLogo-ish way of doing what I think you are trying to do with your code.
to check-pol [m]
ask zsps with [morph = m]
[ let senders zsps with [distance myself <= 20 and morph != m]
set totpol sum [NMaleFlowers * 100 * round (distance myself)] of senders
]
end
Your code gets into levels of ask that I think are unnecessary. What I think you are doing with your list is keeping track of the pollen donors. But an agentset is a cleaner approach and then you can simply pull out the information you want from the agentset using of.
Further, when you ask zsps with[distance myself <= 20 and morph != m] to set variable values in your code, then THOSE agents (not the receiving agent) are the ones having their variables changed. I think you are trying to take the perspective of the receiver of pollen, who looks around and received pollen from the other agents that are close enough. So the receiving agent should have the value changed.
This is not tested.
I'm not 100% sure what you're after here (you may want to look at the Minimum, Complete, and Verifiable Example guidelines), but if I'm reading you right you want the sum of the first item for each entry in the Donners list.
As to why your approach didn't work- NetLogo is telling you with that error that you've used of with a list, but of only works with agents or agentsets. Instead, you have to use a list processing approach. The simplest way might be to use sum in conjunction with map first in order to get what you need:
to sum-first-item
let example-list [ [ 1 2 3 ] [ 4 5 6 ] [ 7 8 9 ] ]
let sum-of-firsts sum map first example-list
print sum-of-firsts
end
To translate to Donnors, try:
set Tot_pol sum map first Donnors
That should work, but without reproducible a code example I can't check.
Greeting,
let assume, I have one manufacture and 10 customers that manufacture create links with some of them randomly(I call these links "contract-links").
One of the properties of manufacture is "real-cost" and one of the properties of customers is "real-waiting-time". "real-waiting-time" is a clear number. Also, Assume service-cost as a global variable.
To calculate the "real-cost", I need the sum of "real-waiting-time" of customers who have links with the manufacture and then multiply in service cost.
I have a question here to calculate "real-cost". How can I call the "real-waiting-time" of all customers and then calculate the real-cost for manufacture?
manufactures-own [ final-costs]
customers-costs [ real-waiting-time]
contract-links [ the-real]
ask manufactures [
final-calculation-for-manufacture
]
to final-calculation-for-manufacture
let the-manufacture self
let the-contract my-contract-links
ask my-contract-links [
set the-real [real-waiting-time] of end2
]
let the-sum sum [ the-real] of my-contract-links
set final-cost the-sum * cost-service-slider
end
It gives me a number, but the answer is wrong.
I think the reason that you are getting the wrong number is that you are doing a lot of setting of the attribute values at the other end of the links instead of getting the information from that link. But your general approach is too complicated - if you have created a link breed called contract-links (which you seem to have), then the agents at the other ends of those links are the link neighbors of agent asking. Try something like this.
manufactures-own [ final-costs]
customers-costs [ real-waiting-time]
contract-links [ the-real]
ask manufactures
[ let the-sum final-costs sum [real-waiting-time] of contract-links-neighbors
set final-cost the-sum * cost-service-slider
]
end
This assumes you want the sum of the waiting times of the linked customers. I couldn't work out what the attribute the-real is for the links.
My turtles have more than 30 attributes of boolean values and I would like to use a foreach loop to compare turtles and rank them based on their similarity without the need to compare each attribute individually. I might be missing an obvious point here, I have tried having a list of attributes, but it didn't work and all turtles got the maximum similarity score.
Here's some code that calculates the Hamming distance between two lists. Note that the very clever reduce code is taken directly from the NetLogo dictionary.
to testme
let ll1 (list TRUE TRUE FALSE FALSE)
let ll2 (list TRUE FALSE TRUE FALSE)
let ll3 ( map = ll2 ll1 )
show ll3
show reduce [ [occurrence-count next-item] ->
ifelse-value (next-item) [occurrence-count + 1] [occurrence-count] ] (fput 0 ll3)
end
If you were wanting to calculate the similarity score of a pair of turtles, you could turn this into a reporter that takes the two turtles as arguments. But it's not clear that comparing two turtles is what you want to do, so I haven't written code for that.
I hope this is a simple solution, but I'm having a difficult time with it.
Problem:
I would like to weight the probability of something occurring by an variable not a constant
Setup
My agent is a farm.
Farms own four variables that represent the
number of cows, goats, pigs, and sheep on it.
When a farm wants to
remove an animal, I'd like the likelihood to remove a member of a
particular species to be directly proportional to quantity of each
species on the farm (i.e. if there are 7 goats, 2 cows, and 1 pig,
there is a 70% probability of taking a goat and a zero percent
probability of taking a sheep)
I have found formula like this for when you know the exact numerical weight that each value will have:
to-report random-weighted [values weights]
let selector (random-float sum weights)
let running-sum 0
(foreach values weights [
set running-sum (running-sum + ?2) ; Random-Weighted Created by NickBenn
if (running-sum > selector) [
report ?1
]
])
end
and the methods described in the rnd extension. But both of these throw the "expected a constant" error when i put "Cow" in instead of a constant.
Something like:
to example1
let values ["Cow" "Sheep" "Goat" "Pig"]
let probabilities [2 0 7 1]
let indices n-values length values [ ? ] ; Made by Nicolas Payette
let index rnd:weighted-one-of indices [ item ? probabilities ]
let loca item index values
end
works well, but if I were to replace it with:
to example1
let values ["Cow" "Sheep" "Goat" "Pig"]
let probabilities [Num-Cows Num-Sheep Num-Goats Num-Pigs]
let indices n-values length values [ ? ] ; Made by Nicolas Payette
let index rnd:weighted-one-of indices [ item ? probabilities ]
let loca item index values
end
it fails.
Alan is right: you need to use the list primitive (as opposed to just brackets) when you want to construct a list from anything else than constants.
I would add two things to that:
The latest version of the rnd extension has two sets of primitives: one for agentsets, and one for lists. So you should probably update and use the rnd:weighted-one-of-list primitive.
Your code is based around using indices to pick an item. That's fine, but that's not the only way to do it.
You could also have something like:
to example1
let values ["Cow" "Sheep" "Goat" "Pig"]
let probabilities (list Num-Cows Num-Sheep Num-Goats Num-Pigs)
let loca first rnd:weighted-one-of-list (map list values probabilities) last
end
This may be a bit trickier to understand, but here is the gist of it:
The (map list values probabilities) expression takes both your values list and your probabilities list and "zips" them together using the list primitive, resulting in a list of pairs: [["Cow" 2] ["Sheep" 0] ["Goat" 7] ["Pig" 1]].
We pass the last reporter to the rnd:weighted-one-of-list primitive to tell it that the last (i.e., second) item of each of these pairs should be used as the probability.
Since rnd:weighted-one-of-list operates on a list of pairs, the item it returns will be a pair (e.g., ["Goat" 7]). We are only interested in the first item of the pair, so we extract it with the first reporter.
Note that we use the NetLogo's concise syntax for tasks when passing list as an argument to map and last as an argument to rnd:weighted-n-of. You could replace list with [ (list ?1 ?2) ] and last with [ last ? ], but it would be uglier.