Running Faster Hec-Ras 2d Models

[Diego Navarro]

Good afternoon,
I have a question un running my models faster, do you guys know if the fastest way to get faster 2d model running is only by increasing CPU speed?, or will more cores help at lower speeds, theirs a document for this in the site but its a bit old from 2016, so I was wondering if you guys know anything new on the topic for hec-ras 6.2?

[Luis Partida]

The corps put out a 2 page document on this exact question.

https://www.hec.usace.army.mil/confluence/rasdocs/r2dum/latest/optimize-your-computer-for-fast-computations

[Scott Miller]

The best way to answer your question is to establish a benchmark and compare the performance of different computers. Be sure to check for differences in volume error. HEC-RAS also allows you to limit the number cores used during simulation on a single computer. In the 2D models I’ve run I find that increasing the number of cores HEC-RAS is using consistently increases simulation speed, albeit with diminishing returns.

There are two more things to consider when trying to get a 2D model to run as fast as possible. 1. Pay attention to what your model is doing. If particular cells are iterating excessively to converge to a solution, or dominating courant condition time step, they may cause a simulation to take hours or days longer. 2. 2D models may take a very long time anyway.

There are quite a few comments on Chris’s post. Be sure to take a look through them.

• This reply was modified 2 years, 2 months ago by Scott Miller.

[Scott Miller]

Odd – the link does not appear to be coming through. Check for the post titled “Optimizing Your Computer for Fast HEC-RAS Modeling” in the RAS Solution. See the comments there.

• This reply was modified 2 years, 2 months ago by Scott Miller.

[Diego Navarro]

Thankyou guys very much! appreciate the help

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