July 23rd 2019

Dave's Top Tip: Enable Parallel Simulations

Dave's Top Tip: Enable Parallel Simulations

Dave’s “top tip” 2

By enabling the use of Parallel processing, Apache can run your calculations up to 85% faster. Using the serial method all calculations would be complete using a single core of your CPU, Apache can now use multiple cores to split the simulation up and run multiple parts at the same time.

How to Enable:

  1. By selecting Tools, User Preferences
  2. Within Simulation settings
  3. You can select Apache to use Parallel simulations

The use of the Apache Task view now enables you to stack calculations, so you could have a design simulating within the background, whilst making modifications to your model, you could then set this revised model to also simulate. By changing the file name within the simulation dialog box, you will get separate results for each simulation within VistaPro.

(Example of Parallel - for multiple serial simulations (get lots of design iterations for comparison and review in time it takes to run a single simulation))

The use of parallel calculations enables you to split each calculation via cores or months. When completing models with lots of rooms, or maybe a low time step simulation, then I suggest the use of this for iterative design work. By enabling the use of months your simulations will include for preconditioning for each period, however this would enable you to simulate your design for each month at a time. Once each section (or month) is complete the results can be downloaded into VistaPro, enabling you to investigate the findings prior to completion of the whole model, this would enable you to investigate the results prior to running the whole year. This is a great function when running models for problem solving, trying to obtain certain reduction requirements or just seeing if your design intent is correct. 

(Example of Parallel - for a single simulation grouped by months (finishes faster))

Use the VistaPro refresh button on the Results tab to import any available results files as simulations complete


I prefer to run the final iteration in serial mode to capture the whole year, including a full initial preconditioning. More information on preconditioning can be found here

A single Apache licence will allow the use of 4 cores, meaning using a single licence will enable you to reduce your simulation time by around 60%. By adding further Apache licences you can unlock the use of more cores (if available), an example of this being the use of 12 core machine (using three Apache licences) would achieve a reduction in time taken to simulate the building design by up to 85%. All speed reductions will be dependent on the model complexity and analysis setup.


Click here to learn more about the use of Parallel Simulations.

If you wish to include the use of this function within your licences then please contact sales@iesve.com for more details.

If you have any ideas for Top Tips to help engineers get the most of VE please let Dave know: david.pierce@iesve.com