What does this code mean?

I'm trying to build a SimEvents model, where entities are assigned attributes that will determine whether they pass through a second loop in the model, or are terminated immediately.

I have the following code (See below) from my supervisor, but can't understand what it means. Any help is appreciated!

___

Found in Entity Generator (Entity Generation tab):

% Pattern: Repeating Sequence
persistent SEQ;
persistent idx;
if isempty(SEQ)
    SEQ = [1 1 1 1 inf];
    idx = 1;
end

%if idx > numel(SEQ)
 %   idx = 6;
%end
x = SEQ(idx);
idx = idx + 1;
dt=x;

___

Found in Entity Generator (Event Actions tab):

% Pattern: Repeating Sequence
persistent SEQ;
persistent idx;
if isempty(SEQ)
    SEQ = [2 2 2 2 2];
    idx = 1;
end
if idx > numel(SEQ)
    idx = 1;
end
entity.Route = SEQ(idx);
idx = idx + 1;

Thank you!

[Rishabh Rathore]

I could explain what every single line is doing but won't be able to explain the utility of the code as other code (i.e. context) is not given.

[Navya Anand]

Ah ok, thank you. Would you be able to explain how I can enter a code such that the nth entity generated has a specific attribute? e.g. 60% attributes proceed down Path1, whilst 40% proceed down Path2 (to be split later on in the model)?

Thank you, Navya

Answer 1

[Jan]

The first code replies a dt=1 for the first 4 calls and dt=inf for the fifth call.

The second code sets the variable entity.Route to 2 in all 5 calls.

[Navya Anand]

Thank you for your answer. Would you be able to explain in very basic terms what "dt" is, and what its function is?

[Jan]

dt is the output of the first code. The posted code does not contain any information which explains, how the value is used in the calling function. In the first call the code performs:

dt = 1

Do you see, that it is impossible to use this information to clarify the meaning of dt?

[Navya Anand]

Yes I can see that - thank you for your help! :)

Answer 2

[Krishna Akella]

Hi Navya,

In the Entity Generator, Entity Generation tab, dt is the amount of time the generator has to wait before it generates the next entity. So it is the delta time to next entity. Or the inter-generation time.

If I understand correctly, you want 60% entities to go down path 1 and 40% to go down path 2. Assuming entity.Route is what is deciding the route later on in your model, you can draw a uniform random number between 0 and 1. If the value is less than or equal to 0.6, then set entity.Route = 1. Else, set entity.Route = 2.

- Krishna