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How to extract entity attributes to use as inputs to either a Matlab or Simulink function?

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Sundar Aditya
Sundar Aditya on 10 Aug 2019
Commented: Renato SL on 14 Aug 2019
I want to plot the minimum delay of an entity over time in a M/M/1 queueing system. This is how I have set up my simulation
My entities have 2 attributes, start_time and rtt. The start_time is initialized (using the start_timer() function) to the current simulation time when entity is generated. Upon service completion, the rtt is computed as the difference between the current simulation time and start time (using the total_delay() function). I am then using a readily available block to extract the rtt attribute, after which I am keeping a running minimum of the rtt using this feedback mechanism (initial condition for the running minimum is inf). However, the probe always shows a 0 signal. Where am I making a mistake? In general, how do I extract entity attributes to either (a) use as inputs to any generic simulink or matlab function, or (b) save to the workspace? Thanks.


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Sundar Aditya
Sundar Aditya on 13 Aug 2019
I believe I've figured out the souce of the error. As @Renato SL said, the problem was with my implementation of the running minimum in the fixed_delay() simulink function. The block to extract the entity attribute sets the attribute value to 0 before the first entity is generated. Since my attribute value is never negative, the running minimum is always 0.
Renato SL
Renato SL on 14 Aug 2019
Good to hear that you have figured out what is the cause of the problem.
Anyway, if you want to share your model, you can either attach it to your question or to a comment like this.
There should be an Attachments button on the INSERT Tab when you are writing a question or a comment.

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