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I am working on a system dynamics model, whose units are days, in AnyLogic. The model tracks daily demand of water for 10,950 days (30 years). One of the model’s outputs is a timeplot that keeps track of this demand, but I don’t want it to plot the daily demand. Instead, I want the timeplot to show demand in years (i.e. the sum of 365 days across the 30 years). I am having a bit of trouble finding a way to do this and would appreciate any help. Thank you!

Vianey Rueda
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  • how are you tracking the daily demand? – Felipe Jul 09 '21 at 06:18
  • I have 6 different kinds of demands, each is calculated in a dynamic variable by multiplying a parameter (that has Gallons Per Capita per Day) with population (which is a stock). All of these demands are added together to create the TOTAL daily city demand – Vianey Rueda Jul 10 '21 at 06:16

1 Answers1

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I assume your problem is twofold.

  1. How to get the time plot to display 30 years of data
  2. How to sum the annual demand for 30 years

Here is a simple example that I believe answers your question.

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In this simple model, there is a daily event that simulates the daily demand, and adds it to a variable called annualDemand

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There is another event that runs yearly and tasks the annualDemand and saves it to a data set, and rests the annual demand accumulator to 0.

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In your time plot, you simply display the dataset which will at the end of the model only contain 30 entries, one for each year.

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By following the same principles

  • Save annual demand
  • yearly event to add annual demand to data set and reset the annual demand
  • time plot to plot the dataset

You should be able to get what you need.

Jaco-Ben Vosloo
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  • Thank you for this! Could you speak more to the code that’s in the daily event (annualDemand += uniform discr (10))? I’m not sure I understand this. My daily demand is calculated by the product of dynamic variables and parameters. – Vianey Rueda Jul 10 '21 at 01:31
  • `annualDemand += uniform discr (10))` is the same as `annualDemand = annualDemand + uniform discr (10))` so it just increases the annual demand by some random number between 0 and 10. Since I do not have the details about your exact implementation I just created some sample code. I you find the answer useful remember to accept it – Jaco-Ben Vosloo Jul 11 '21 at 06:28
  • I haven’t been able to get the events to work. The way I calculate emend is as follows: I have 6 different kinds of demands, each is calculated in a dynamic variable by multiplying a parameter (that has Gallons Per Capita per Day) with population (which is a stock). All of these demands are added together to create the TOTAL daily city demand. These daily demands I need to add up for each year. – Vianey Rueda Jul 11 '21 at 19:04
  • You need to record the total daily demand where you calculate it and then store it to the variable. It is hard to provide more meaningful advice without a better understanding of your model. Can you either add more details to your question or perhaps post a new one. Since it is a System Dynmics model you might be able to simple record the change in the variable from one time period to the next – Jaco-Ben Vosloo Jul 12 '21 at 05:00