I am trying to make turtles move along fixed paths that the user can draw in the u.i. The forward command can make turtles move a certain fraction of a patch forward per tick I assume, however to instigate smooth movement would it be possible to specify a fixed movement per tick in the setup commands for turtles? If this is possible what would be the basic structuring of the code I would use to achieve this?
The fd command (bk as well) accept floating-point inputs. I.e.
Ask turtles [ fd .01 ]
Makes each turtle move forward 1/100th of a patch. This movement happens at the time of the command.
Tick does not have any connection to when commands are carried out. If you set view updates to on ticks it can effect when you see updates otherwise it is usually a scheme for keeping track of how many times go has run.
A sample model of turtles moving at different speeds.
Turtles-own [speed]
To setup
Crt 100[
Set speed random-float 1
]
End
To go
Ask turtles[ rt 1 fd speed]
End
Copy and paste that into a new model make setup and go buttons. Mess with it for a while.
I am trying to create a program in netlogo where there are blocks that come down the screen and when their y-coordinate reaches a certain value they reverse their direction and move in the opposite way.
So far I was able to make them move in one direction and then switch directions when they reach the critical y-coordinate value, but once they take one step in the reverse direction it glitches and they get stuck moving one step forward and one step backward.
I wanted to know if there was an else command in netlogo so I could specify that if the while command wasn't fulfilled it could reverse its direction and move without glitching.
Here is my code.
to maze
while [abs pycor < 16 ] [fd 1 wait .1]
bk 1 wait .1
end
There is no separate else keyword in NetLogo, but the ifelse command allows you to specify two blocks: one that is executed if the condition is true, and another (the "else" block) that is executed if the condition is false.
It seems, however, like you should rethink your general approach to the problem. Turtles in NetLogo always face in a particular direction, and you could take advantage of that: instead of having them "back up", you could have them turn around.
Also, it's generally ill-advised to try to do things in a while loop. If you want your turtles to repeat a behavior, a "forever button" is usually the way to go.
In the following example, you should call the go procedure from a forever button:
to setup
clear-all
ask patches with [ pycor = max-pycor - 1 ] [
sprout 1 [
set heading 180 ; head down
]
]
reset-ticks
end
to go
ask turtles [
if abs pycor = max-pycor [
rt 180 ; turn around!
]
fd 1
]
tick
end
This probably doesn't achieve exactly what you wanted, but there is a good chance that you can modify it to fit your needs.
Also note that this will work better using tick-based updates.
In my go function I have a few conditions which might be true and then call an action, if more than one condition are true does it mean in one tick agents can do more than one action ? or in another case I have a function that agents have to move to a target and after facing the target agent should find the distance and fd 1 until reaches the target, does it mean it should take n ticks to complete?
to move [t]
face t
let n distance self t
repeat n
[fd 1]
end
to go
action 1 = > [move]
action 2
action 3
tick
end
I need the agents to do only one task at the time, and I am not sure how to make sure that for example not all the agents have the same target! sorry if these questions are out of context but I am new to Multi-agent modeling.
This is a great question!
First, specific answers:
if more than one condition are true does it mean in one tick agents can do more than one action ?
Just to be clear, are you talking about a situation like this?
to go
ask turtles [ move ]
tick
end
to move
if xcor > 5 [ fd 1 ]
if ycor > 7 [ rt 15 ]
if color = red [ bk 2 ]
end
If so, then yes, if xcor > 5, ycor > 7, and color = red are all true, the turtle will move forward 1, turn right 15, and move backward 2. The main way to prevent this is by using a sequence of ifelses:
to move
ifelse xcor > 5 [
fd 1
] [
ifelse ycor > 7 [
rt 15
] [
if color = red [ bk 2 ]
]
]
end
That way, the second condition (ycor > 7) will only be looked at if the first condition (xcor > 5) is false. Similarly, the third condition will only be looked at if the first two fail.
I have a function that agents have to move to a target and after facing the target agent should find the distance and fd 1 until reaches the target, does it mean it should take n ticks to complete?
I would recommend taking n ticks to complete it. Otherwise, only one turtle will move to its target at a time! However, repeat n [ fd 1 ] will make the turtle go forward n all at once. In fact, it's the same as fd n. The repeat block will finish before the turtle is done performing the move procedure.
You can edit your move function as follows to get it to take n ticks:
to move [t]
face t
fd 1
end
Then, just have a condition to look for when the turtle gets to its target (for example, distance t < 1) and then do something accordingly.
I recommend just messing around with these various techniques with multiple turtles using them so you can get a feel for the differences.
I am not sure how to make sure that for example not all the agents have the same target!
This depends quite a bit on context. Supposing there is a turtles-own variable called target that stores each turtle's target, you could do something like this:
to-report get-available-target [ possible-targets ]
report one-of possible-targets with [ not any? turtles with [ target = myself ] ]
end
get-available-target will report a random agent from possible-targets that is not anyone's target. one-of just gets random agent from an agentset.
How can I schedule tasks in netlogo, I have conditions and actions but how can I make the agents do one task at the time?
Often this just takes care of itself. For example, say, when an agent is hungry, it should walk over to a food supply and eat. As it's walking over, you don't want it to go off and do anything. However, it will still be hungry, so if you've used an ifelse, it will just keep going to the food supply. Thus, your agent stays focused for free! In general, it's best to design your conditions such that they remain in effect until the agent addresses them. You can order them in an ifelse chain or something similar to establish the general priority of actions (for instance, if the agent walking to the food supply is threatened by a predator, it should still run away).
If you really want to the agent to do something for several ticks, you'll basically just extend this same idea, but in a more artificial way. For instance, if an agent should walk forward three times, have a turtles-own variable set to three. If that variable is greater than zero, the agent walks forward and decreases that variable, and doesn't do anything else.
#Bryan Head already answered your question, I had the same problem when I started Netlogo and agent based modeling, So I have added a current-task variable and in my Go Procedure I have added a function to check all the conditions and set the task of agents and when the task is completed the variable is set to "" again. This might be useful for your case as well.
if current-task = "move" [move]
if current-task = "A1" [A1]
if current-task = "..." [...]
if current-task = "" [select-current-task]
im creating a a model of the classic arcade game dig dug in netlogo. So I tried o create a level and have monsters moving 3 steps forward and 3 steps back constantly in their areas but when i try to play the game lags and becomes very slow. please help
to stalk
ask monsters
[
fd 1 wait .1
fd 1 wait .5
fd 1 wait .5
bk 1 wait .5
bk 1 wait .5
bk 1 wait .5
]
end
i tried putting this code as a forever button but then the game becomes slow. how do i set the monsters to pace around constantly while the hero moves around in the game?
(plz review dig-dug if your not sure what it is]
The lag is coming from the use of wait.
You should regulate the speed of your monsters by using mod with ticks or by having a 'speed' variable. Here's example code for the first approach:
; move monsters every 10th tick
to move-monsters
if ticks mod 10 = 0 [ask monsters [fd 1]]
end
I'm new in NetLogo.
I have a set of turtles and some predators.
When the turtles see one or more predators in their vision-radius, they move quickyly away.
What I want to change is the speed of the turtles, I'd like they change their speed gradually at each tick.
I tried to use this code but it doesn't work. Acceleration is a slider that goes from 0.0001 to 0.0099.
to avoid
turn-away (towards nearest-predator) max-avoid-turn
set speed speed + acceleration
fd speed
end
How can I do?
Thank you!!
Set your acceleration slider from 0 to 1 and put it at 1. If you don't see anything noticeable after that, you'll have to lend us more context. However, I think that should do the trick.