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Old   November 22, 2004, 08:52
Default dual processing
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could anyone inform me about the effectiveness of a system with 2 processors (pentium 4 for example) on windows platform? is the cpu power getting doubled? thanks

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Old   November 22, 2004, 09:59
Default Re: dual processing
Ralf Schmidt
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I dont know about cpu power. But I can tell you, that Fluent might have problems with parallel processing.

We are using Workstations with 2 processors, and some thing doesnt work. For excample importing a mesh from gambit with two fluid zones (one fluid, the other one porous) is not possible. This just works with a normal PC. Also Floating point error might occur, referr to:

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Old   November 22, 2004, 13:23
Default Re: dual processing
Evan Rosenbaum
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We have dome some dual-processor runs in the past (v5.5). Fome some problems the increase in throughput was actually more than doubled. We think this is because FLUENT is optimized for parallel processing and required less iterations. Other runs were say 1.6-1.8 times faster.

Some things can't be run parallel (DTRM radiation for example).
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Old   November 22, 2004, 13:24
Default Re: dual processing
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I am using Fluent parrallel on Windows XP, with single P4 processor and Hyper Threading enabled.This results in software seeing two processors.

This has resulted in significant savings of time, each alternate iteration is done on different processor so solving time is reduced.

regards MML
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Old   November 22, 2004, 20:24
Default Re: dual processing
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i agree with ralf, that fluent has this problem if you have two zones, but after a lot of effort and you are lucky it can read this multizonal mesh also, in my case i had to make mesh around 10 times, with lot of tricks (i mean defining them as say solid rather than fluid zone , or interface to wall etc),
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Old   December 2, 2004, 15:23
Default Re: dual processing
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This is a common problem that we (cd-adapco) see sometimes from customers who have switched over to StarCD from Fluent. The new solver from from CD Star-CCM+ has been specifically written from the ground up to take advantage of parallel processing. An old code, (like Fluent) has tried to add parallel processing after the fact. It only works for certain cases and not all models and I think that this is what you are running into

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