Скачать или смотреть How to Perform Aggregation on a Subdimension of a System Dynamics Array in AnyLogic

Discover how to sum values in a `subdimension` of a System Dynamics array using AnyLogic. Learn practical steps to manage age groups efficiently!
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Solving the Aggregation Challenge in AnyLogic's System Dynamics Arrays

When working with System Dynamics in AnyLogic, you may find yourself facing a common problem: how to efficiently aggregate data based on specific subdimensions of an array. This issue becomes particularly relevant when you're dealing with demographic data, such as calculating the total number of children in an age-specific model.

The Problem at Hand

Imagine you have a large System Dynamics (SD) array named people that represents individuals categorized by their age. This array includes a dimension for Age that encompasses every single year. To make your analysis meaningful, you’ve also created subdimensions labeled Child and Adult:

Child: Includes ages from 0 to 17

Adult: Includes ages from 18 and above

Your goal is to calculate the total number of children using the aggregation function, but you’ve discovered that the built-in aggregation method people.sum(Index_Can_Vary) sums across the entire age dimension rather than just the subdimension representing children. So how do you get this desired subset summation?

The Solution

Unfortunately, as per the current capabilities of AnyLogic, you cannot directly perform aggregation on a subdimension of the SD array. However, you can employ a straightforward looping approach to achieve the desired total sum for children. Here’s how:

Step-by-Step Guide to Aggregate a Subdimension in AnyLogic

Initialize a Sum Variable: Start by creating a variable to store the cumulative sum of the children.

[[See Video to Reveal this Text or Code Snippet]]

Iterate Over the Child Ages: Use a loop to iterate through the child ages (from 0 to 17).

[[See Video to Reveal this Text or Code Snippet]]

In this code block:

The for loop runs from 0 through 17, which corresponds to the ages of children.

The people.sum(Child.indexes[i]) aggregates the counts of people for each specific age indexed by the Child subdimension.

Output the Result: Now that you have computed the total number of children, you can utilize this value within your model as needed.

Why This Approach Works

Flexibility: By manually summing over the child ages, you gain control over your aggregation process, enabling focused calculations that respect the specific demographic structures within your model.

Simplicity: This method is straightforward and easy to implement, making it suitable for users who may not be deeply familiar with advanced AnyLogic functions.

Conclusion

While AnyLogic does not provide an automatic way to sum over subdimensions directly within its aggregation functions, the workaround outlined above allows users to achieve their desired results effectively. By employing a simple loop to sum your indexed values, you can easily calculate the total number of children in your system dynamics model.

Feel free to adapt this strategy for other demographics or subdimensions as required in your projects!