ERROR: Tried to remove agent with ID 66 from the space, but that agent is not on the space

Specific Domains Modelling & Simulations
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4

Hello, :slight_smile:

Solution to problem is : move_agent!(agent, new_position, model)

Use above line in agent_step() before moving the agent.

Check out this code:


@agent struct PoorSoul(ContinuousAgent{2, Float64})
mass::Float64
end

function handle_collision(agent, model)
    x, y = agent.pos
    vx, vy = agent.vel
    if x ≤ 0.0
   
        x = 0.0
        vx < 0.0 && (vx = -vx)
    end
    if x ≥ model.max_bound
   
        x = model.max_bound
        vx > 0.0 && (vx = -vx)
    end
    if y ≤ 0.0
  
        y = 0.0
        vy < 0.0 && (vy = -vy)
    end
    if y ≥ model.max_bound
   
        y = model.max_bound
        vy > 0.0 && (vy = -vy)
    end
    return  @SVector([x, y]),  @SVector([vx, vy])
end

function initialize(;
    speed = .002,
    interaction_radius = 0.012,
    dt = 1.0,
    max_bound = 1,
    n_agents,
    )
    properties = (;
            interaction_radius,
            dt,
            max_bound,
    )
    space = ContinuousSpace((1, 1); spacing = 0.02, periodic = false)
    model = StandardABM(
            PoorSoul,
            space;
            agent_step!,
            model_step!,
            properties
    )

    # Add initial individuals
    for _ ∈ 1:n_agents
        pos = Tuple(rand(Uniform(0, max_bound), 2))
        mass = 1
        vel = sincos(2π * rand(abmrng(model))) .* speed
        add_agent!(pos, model; vel, mass)
    end
    return model
end

function model_step!(model)
    r = model.interaction_radius
    for (a1, a2) in interacting_pairs(model, r, :nearest)
        elastic_collision!(a1, a2, :mass)
    end
end

function agent_step!(agent, model)
    new_position, new_velocity = handle_collision(agent, model)
    agent.vel = new_velocity
    # this move_agent function changes agent to new position
    # Before you were giving new value to position but agent position was not 
    #actually getting updated. 
    move_agent!(agent, new_position, model)
    move_agent!(agent, model, model.dt)
end

Random.seed!(658)
model = initialize(; n_agents = 10, max_bound = .40)
run!(model, 40)

abmvideo(
    “socialdist4.mp4”,
    model;
    title = “SIR model”,
    frames = 300,
    #agent_color = sir_colors,
    agent_size = 10,
    spf = 1,
    framerate = 20
)
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