AnyLogic - Modifying agent variable

Question

In AnyLogic, I am trying to make a little service loop based on a variable inside an agent. For some reason, my variables are not changing as I expect and I can't make it work.

In my block selectHowMany i have the following code, that is supposed to modify the variable inside customer population:

ped.howMany = ped.howMany + 1.0
ped.howMany = ped.howMany + 2.0
ped.howMany = ped.howMany + 3.0
ped.howMany = ped.howMany + 4.0
ped.howMany = ped.howMany + 5.0

my model with selectHowMany block open

Then, I want the output to determine wether the ped should go to service or to sink, depending if the howMany variable is greater than 1 or not. For that I have another boolean variable isItEnough inside customer population and 'if' statement in output block.

  if(agent.howMany < 1.0){
    agent.isItEnough = false;
}

Condition:

agent.isItEnough = true

output properties

Lastly, at the exit of each of the service blocks I have the following code, so that the variable is actually modifying based on pedestrian's actions:

ped.howMany = ped.howMany - 1.0

My intention was, that pedestrian entering the selectHowMany block will define the variable inside the customer population determining how many times will this pedestrian use one of the service blocks.

No matter how I try the pedestrian is never seizing using blocks (no matter which selectHowMany output it exits), so something is not correct with modifying the variables. The ped is in continuous loop and it never reaches sink.

I hope someone will be able to help me.

Many thanks, Peter

Answer 1

For the condition you need to use two equal signs, not one.

agent.isItEnough == true

That is one mistake I was able to identify... if this doesn't solve it, let me know.

Another problem is AnyLogic evaluates the select output condition before it enters the block. Refer to this other question: Unexpected behavior SelectOutput block in AnyLogic

So when you add an action in the On Enter of the select output, it will not impact the decision of that select output. One way to solve it, as mentioned in the link I shared, is to add a dummy delay of 0.01 millisecond for example before the select output element in which you place the following code:

 if(agent.howMany < 1.0){
    agent.isItEnough = false;
}