LevelSpace in Netlogo: "The tick counter has not been started yet" error, but tick has indeed been reset

Question

I am starting with LevelSpace extension in NetLogo. I have two version of my code: one does not do what I want, but throws no error: the other does as expected, but only for the first tick, than throws The tick counter has not been started yet. Use RESET-TICKS. error while observer running TICK called by procedure GO called by Button 'go'.

Here are the two snippets of code (note that there are absolutely no error in the netlogo app that this code call).

A) Does not do what I want, but at least run:

to setup
    ls:reset
    ca
    ls:create-interactive-models number_worlds "FlockingModified.nlogo"
    ls:ask ls:models [ setup ]
    reset-ticks
end

to go
    clear-all
    ls:ask ls:models [ go ]
    let number_centroids [count centroids] ls:of ls:models
    let x_centroids [ListXCentroids] ls:of ls:models
    let y_centroids [ListYCentroids] ls:of ls:models
    let heading_centroids [ListHeadingCentroids] ls:of ls:models
  
    foreach ls:models[
        i -> let id_world i
        let number_centroid item id_world number_centroids
        let xcoords item id_world x_centroids
        let ycoords item id_world y_centroids
        let headings item id_world heading_centroids
        loop [
            if number_centroid = 0 [stop]
            create-turtles 1 [
                set color 15 + 10 * id_world
                setxy last xcoords last ycoords
                set heading last headings
        ]
        ;this is a home made pop, equivalent to java pop
        set xcoords but-last xcoords
        set ycoords but-last ycoords
        set headings but-last headings
        set number_centroid number_centroid - 1
    ]
    
    tick
end

The problem is that it does not change id_world. I tried a loop version. models is obtained with let models ls:models.

loop[
    if empty? models [stop]
    let id_world last models
    let number_centroid item id_world number_centroids
    let xcoords item id_world x_centroids
    let ycoords item id_world y_centroids
    let headings item id_world heading_centroids
    loop [
        if number_centroid = 0 [stop]
        create-turtles 1 [
            set color 15 + 10 * id_world
            last xcoords last ycoords
            set heading last headings
        ]
        ;this is a home made pop, equivalent to java pop
        set xcoords but-last xcoords
        set ycoords but-last ycoords
        set headings but-last headings
        set number_centroid number_centroid - 1
    ]
    ;;it never gets to here
    set models but-last models
]

Then I have the while version, that throws the error but does what I expected:

let models ls:models
while [not empty? models] [
    let id_world last models
    let number_centroid item id_world number_centroids
    let xcoords item id_world x_centroids
    let ycoords item id_world y_centroids
    let headings item id_world heading_centroids
    while[number_centroid > 0] [
        create-turtles 1 [
            set color 15 + 10 * id_world
            setxy last xcoords last ycoords
            set heading last headings
        ]
        ;this is a home made pop, equivalent to java pop
        set xcoords but-last xcoords
        set ycoords but-last ycoords
        set headings but-last headings
        set number_centroid number_centroid - 1
    ]
    set models but-last models
]

Answer 1

clear-all also includes clear-ticks which undoes your reset-ticks, so calling that in your go leads to this error. If you want certain things cleared you will have to do so with separate clear commands such as clear-turtles, clear-patches, and clear-globals.