Thursday, August 12, 2010

Get started with Entry-Level HPC and ANSYS

Ansys Mechanical has supported and been tightly integrated in the High Performance Computing (HPC) arena for many years and many versions. However, I've seen a quite some hesitation from users and companies to introduce HPC into their engineering simulation environment. Reasons generally come down to cost and complexity.

True, setting up a central cluster with many nodes is costly. The complexity of configuring it, optimizing it (for Ansys and the other array of applications that will share it), and maintaining it can be daunting.
However, I've worked with a large number of customers recently getting into "entry level HPC". Even though our primary workstations are getting more powerful (6-core processors are here, 12-core processors are coming soon) and we're able to run larger jobs on them, there's still a need to offload the job to an HPC environment. Let's face it - we've all closed our emails, web browsers, and office apps during those painfully slow solves to try a free up just a few more Mb's of ram, hoping the run won't crash.

What I consider "entry-level" is to have at minimum a 2nd workstation (or server), can be high or low end, expensive with lots of CPU/RAM/disk space, or inexpensive (assembled from all those spare components laying around). The idea here is to try HPC - a simple setup to send a solve over to a 2nd computer. If you have the compute power in your 2nd computer for high-end analysis, great! If not, get something set up to at least introduce yourself to the concepts and see how it works.

I recently worked with a customer who purchased a very high-end single-node compute server. Why just one? Simple answer... cost constraints. We were able to set it up, get the Ansys users up and running and accustomed to HPC (and adopting its advantages) and then when the budget allowed, the customer added additional compute nodes to the existing cluster.

Off-loading the solve can be done a number of ways, including Remote Solve Manager (RSM), batch scripts, Distributed Ansys, even simply using Remote Desktop. (Great discussion points for future topics!) This simple "entry level HPC" setup can free up your primary workstation during those intensive solves. It is amazingly convenient to build a model on my laptop, hit "Solve", shut down my laptop, go home, and come in the next morning with a fully solved model!

I love to hear your thoughts!


Tuesday, August 10, 2010

When NOT to use comparative Charts for CFD software

Recently there was an article in Desktop Engineering where it compared several commercial CFD products in the marketplace today. I am all for this! Sure! What shocked most in the industry who read this article was how terribly inaccurate this was and how biased it was towards one single product. I wish it was featured in a "marketing section" vs. an engineering magazine such as Desktop Engineering. In this rebuttal article from Mentor Graphics (Dr. J), the author claims to even have received an apology from Desktop Engineering: "To their credit, when we notified them, Desktop Engineering apologised to us, sent out an apology to all of its readership and promised that such a chart would not go out again."

Here is a direct link to the rebuttal article: "Lies, Damned Lies, and "CFD Comparison Charts" - Part I" You can also see the original "comparative charts" here as reference.

In this article, Dr. J aptly points out the one-sided take by CF Design. Though he mainly talks about improper comparison of Mentor Graphics' FloEFD, there are several inaccuracies on this comparative chart when it comes to ANSYS CFD products (FLUENT, CFX) as well. Any current FLUENT and CFX user can testify to these inaccuracies! Dr. J, the count on "misleading statements" in the DE article are well beyond 27 if we include the ANSYS CFD products. I still don't believe this article ever got published! It begs more research and accurate information.

Having been in the simulation industry (FEA, CFD) for close to a decade, this false comparative chart regarding CFD products is really appalling, especially coming from a magazine such as DE. Negative marketing campaigns are not a good idea. If you do them, please know the facts about competition first! And then do not do it as a "guide" to helping engineers decide on what CFD code to chose!

Update: Folks from Blue Ridge Numerics have responded on LinkedIN forums on this and seems like they are working on it. Good to know:) You can follow their comments here:

I look forward to your feedback.