Debugging allocator modelling error

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Nikhil Pillai

• July 16, 2025 05:29
• Edited

Hi,

I am modelling a large scale water management system for a mine site. The model uses allocator function to transfer water from one dam to multiple dams. Here there is a chance of error occurring if the same outflow from the allocator is used as inflow to 2 dams (modelling error). This creates a mass balance error due to double counting the allocator outflow value.
For a complex system (say 100 dams) it becomes hard to identify which allocator outflow is causing the error. Is it possible to identify it without going through each outflow of each allocator?

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  Jason

  • July 16, 2025 21:25

  Nikhil,

  I recommend that you use our mass balance example by copying this container into each of your reservoir locations and hook up inflows, outflows, and storage as directed in this example. This is a good way to keep track of mass balance at all locations separately. But since you have so many (100), then I would recommend that you group them into manageable chunks like 5 or 10 reservoirs and hook up the mass balance check for all of the group. Keep in mind that you draw an imaginary boundary around the group of reservoirs and track only the flows across that boundary (in and out) and sum the total storage in the group. 

  This is a bit of work but once you get it up and running, you have a continuous mass balance checker that will inform you of the group causing the error, to better help you zero in on the problem. 

  Here is a link to that model: Check for Mass Balance Closure – GoldSim Help Center

  Unfortunately, there is not an automated way to account for these flows, since we allow you to connect flows from any output as long as the data type matches.

  Does that help?

  Jason

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  Nikhil Pillai

  • July 18, 2025 01:06

  Thanks Jason. I use the "Check for mass balance closure" in the model. I believe grouping the reservoirs for mass balance check is a good solution. I was also wondering if there is a way to get a list of all the function elements and its 'affects' elements in the model, maybe using an API?

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  Jason

  • July 18, 2025 21:11

  Nikhil,

  Good question about the way to find function elements. When you say "function elements" if you mean the Expression element, then there is always the Class View of the browser where you can see the list of all Expression types: Using the Browser. 

  Another option is to export the Model Inventory, which can be done from the File menu in your model. Creating an XML Model Inventory File

  Note - the model inventory doesn't show input definitions or expressions. It only shows the element IDs, descriptions, and the Containment in a hierarchical structure inside an XML file. It does show the values of Data elements. 

  Regarding the function of and affects views, you will need to view those inside GoldSim using the right click browser option. Viewing Element Dependencies.

   

  I hope this helps,

  Jason

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  Nikhil Pillai

  • July 21, 2025 00:17

  Thank you Jason.

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