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-   -   Ubuntu 12.10 64bit: To compile or not? (http://www.cfd-online.com/Forums/openfoam-installation/111712-ubuntu-12-10-64bit-compile-not.html)

CrazyFatDude January 13, 2013 21:45

Ubuntu 12.10 64bit: To compile or not?
 
Hi everyone,
I have put together a new computer with intel core i7 3930K, 32GB Ram, 1TB hdd, nvidia GTX 570. I'll install Ubuntu 12.10 and I would like to install OpenFoam for everything CFD, my questions are:

1. Are there any gains in compiling OpenFoam from source vs. installing from the binary file?
2. If compiling from source is the way to go, which compiler should I go for, will ICC be the obvious choice? Or does the latest version of GCC have the edge?
3. Do I need code vectorization, or use of pragmas to achieve better performance? I'm no expert on these terms but I have seen them mentioned in threads discussing GCC vs ICC.

Thanks.

wyldckat January 14, 2013 05:10

Greetings CrazyFatDude,

In quick reply:
  1. Yes. One reported here on the forum indicated an increase of performance of 50%, at least a couple of years ago.
  2. You'll have to try it for yourself. It may depend from case to case. Some reports say that ICC is best and others say that GCC 4.5 and above can be around 5% faster.
    Some hints on this can be found here: http://www.cfd-online.com/Forums/blo...-amd-cpus.html - don't mind the crazy ranting post, but there is good information there, mainly in the comments.
  3. Yes, AFAIK, it's good to use everything your CPU has to offer.
  4. Not asked, but even if your CPU has Hyper-Threading, it's useless to use the threads with OpenFOAM: http://code.google.com/p/bluecfd-sin...SE_12.1_x86_64
Best regards,
Bruno

CrazyFatDude January 14, 2013 05:18

Thanks a lot Bruno, sorry if I posted in the wrong forum. I'll keep coming to this thread and report my findings & further questions.

Thanks again.


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