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-   -   Parallel processor (http://www.cfd-online.com/Forums/fluent/110872-parallel-processor.html)

ArmanZohrabi December 23, 2012 07:45

Parallel processor
 
Hi boys!
I use fluent 6.3.26 and i find that FLUENT only use one core (13% of CPU). How could I make Fluent use all cores?

jdrch December 23, 2012 15:28

I'm not sure about version 6.*, but in 13*+ you enable multicore at the beginning of each session by selecting "Parallel" instead of "Serial" at the start.

LuckyTran December 23, 2012 16:53

Quote:

Originally Posted by jdrch (Post 398809)
I'm not sure about version 6.*, but in 13*+ you enable multicore at the beginning of each session by selecting "Parallel" instead of "Serial" at the start.

Version 6 is identical to 12+ except the interactive window looks different (older).

In the interactive window choose "Parallel" or

If starting with scripts then you need to add -pe # to the script (parallel environment, # of cores)

fangdian December 25, 2012 10:28

Quote:

Originally Posted by LuckyTran (Post 398812)
Version 6 is identical to 12+ except the interactive window looks different (older).

In the interactive window choose "Parallel" or

If starting with scripts then you need to add -pe # to the script (parallel environment, # of cores)

IN FLUENT6.**, you can run fluent in parallel in this way: run the command: *fluent install directory*\fluent 3ddp -t2
(if its operation system is windows, and you want to use 2cores in CPU,3d,double precision in fluent)

ArmanZohrabi December 25, 2012 17:53

Quote:

Originally Posted by fangdian (Post 398976)
IN FLUENT6.**, you can run fluent in parallel in this way: run the command: *fluent install directory*\fluent 3ddp -t2
(if its operation system is windows, and you want to use 2cores in CPU,3d,double precision in fluent)

hi, thanks for your attention !
but i think that dp or double precision that you said isn't about cpu usage, it is about answer accuracy, isn't it ?
another thing is that my cpu is i7 and I want to parallel 4 cores by fluent 6.3.26

jdrch December 25, 2012 18:33

Quote:

Originally Posted by ArmanZohrabi (Post 399001)
another thing is that my cpu is i7 and I want to parallel 4 cores by fluent 6.3.26

If the interactive window for version 6 is identical to 12 as LuckyTran said, you should be able to select the number of parallel processes you want to use right after you select "Parallel."

LuckyTran December 25, 2012 18:53

Quote:

Originally Posted by ArmanZohrabi (Post 399001)
hi, thanks for your attention !
but i think that dp or double precision that you said isn't about cpu usage, it is about answer accuracy, isn't it ?

The dp is there for another reason, you must launch Fluent in the intended environment. If you do not want double precision (who even uses single precision these days?) then you need to use 3d instead of 3ddp. If you want 2d then use 2d instead of 3d. But there must be an environment.

Quote:

Originally Posted by ArmanZohrabi (Post 399001)
another thing is that my cpu is i7 and I want to parallel 4 cores by fluent 6.3.26

It doesn't matter what cpu you have. Fluent version doesn't matter unless you have more than one Fluent installation.

If you want to do a 3d simulation, with double precision, AND 4 parallel threads then you need to use 3ddp -t4 (t is the number of threads)

If you only put -t4 (meaning you want 4 parallel threads) Fluent still does not know what the environment is and will not launch (i.e. 2d versus 3d, sp versus dp). Also note, the 3ddp must come before the # of threads you want to use.

Additional Examples:
all in serial environments
2d
2ddp
3d
3ddp

in parallel with # cpu's
2d - t#
2ddp -t#
3d -t#
3ddp -t#

Quote:

Originally Posted by ArmanZohrabi (Post 398767)
Hi boys!
I use fluent 6.3.26 and i find that FLUENT only use one core (13% of CPU). How could I make Fluent use all cores?

By the way, if you have a quad core then Fluent should be using up 25% of the cpu (i.e. 100% of 1 core). If it is running consistently at 13% then you have a memory bottleneck. Switching to a parallel environment will not do you any help if there is a memory bottleneck.

ArmanZohrabi December 27, 2012 17:19

Quote:

Originally Posted by LuckyTran (Post 399003)
The dp is there for another reason, you must launch Fluent in the intended environment. If you do not want double precision (who even uses single precision these days?) then you need to use 3d instead of 3ddp. If you want 2d then use 2d instead of 3d. But there must be an environment.



It doesn't matter what cpu you have. Fluent version doesn't matter unless you have more than one Fluent installation.

If you want to do a 3d simulation, with double precision, AND 4 parallel threads then you need to use 3ddp -t4 (t is the number of threads)

If you only put -t4 (meaning you want 4 parallel threads) Fluent still does not know what the environment is and will not launch (i.e. 2d versus 3d, sp versus dp). Also note, the 3ddp must come before the # of threads you want to use.

Additional Examples:
all in serial environments
2d
2ddp
3d
3ddp

in parallel with # cpu's
2d - t#
2ddp -t#
3d -t#
3ddp -t#


By the way, if you have a quad core then Fluent should be using up 25% of the cpu (i.e. 100% of 1 core). If it is running consistently at 13% then you have a memory bottleneck. Switching to a parallel environment will not do you any help if there is a memory bottleneck.


Thanks a lot man !!

a.zareinezhad March 10, 2013 18:41

easy way!
 
just right click in fluent icon in your desktop
in properties > shortcut tab > target

change
C:\Fluent.Inc\ntbin\ntx86\fluent.exe -r6.3.26
to:
C:\Fluent.Inc\ntbin\ntx86\fluent.exe -t6.3.26
now run the fluent
now you may see some message like this in fluent :

(Loading "C:\Fluent.Inc\fluent6.3.26\lib\fl114.dmp"
Done.
version>


now go to
file tab > run > and choose parallel type
in option > processes you can choose how many core do you want to use
be careful you should use one or 2 core less than your avalable core that your computer has.
:cool:



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