CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Bugs

%24WM_64 not defined in FC5 x8664

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   August 7, 2007, 01:46
Default Description: I downloaded Op
  #1
New Member
 
Greg Collecutt
Join Date: Mar 2009
Location: Brisbane, Queensland, Australia
Posts: 21
Rep Power: 8
gcollecutt is on a distinguished road
Description:
I downloaded OpenFOAM 1.4.1 and attempted to compile from scratch under Linux FC5 x86-64. The OpenFOAM-1.4.1/.OpenFOAM-1.4.1/bashrc script did not detect the 64 bit OS and as I only have the 64bit versions of the X11 libraries available, the compiliation failed. As a work around, I put "export WM_64=Y" in my $HOME/.bashrc file just prior calling the ". OpenFOAM-1.4.1/.OpenFOAM-1.4.1/bashrc" line.

Platform:
Linux 2.6.19-1.2288.2.4.fc5 (x86-64)

Version:
OpenFOAM 1.4.1
gcollecutt is offline   Reply With Quote

Old   August 7, 2007, 02:41
Default This is a feature, not a bug.
  #2
Senior Member
 
Mark Olesen
Join Date: Mar 2009
Location: http://olesenm.github.io/
Posts: 777
Rep Power: 18
olesen will become famous soon enough
This is a feature, not a bug.
The default is 32bit. If you wish to compile and use 64bit (on a 64bit machine) you need to set WM_64 to something (as you did).
olesen is offline   Reply With Quote

Old   August 7, 2007, 02:41
Default This is not a bug, OpenFOAM is
  #3
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 13
henry is on a distinguished road
This is not a bug, OpenFOAM is setup to build either 64bit or 32bit on a 64bit machine and 32bit is the default. To select a 64bit build you set WM_64.

Generally we run 32bit even on 64bit machines as on some machines it is faster and always takes less storage. On recent 64bit machines the 64bit version is faster and in future releases we will make the 64bit build the default on 64bit machines.
henry is offline   Reply With Quote

Old   August 7, 2007, 20:25
Default When compiling double precisio
  #4
New Member
 
Greg Collecutt
Join Date: Mar 2009
Location: Brisbane, Queensland, Australia
Posts: 21
Rep Power: 8
gcollecutt is on a distinguished road
When compiling double precision code, I have ALWAYS found 64 bit code much faster than 32 bit code. As double precision compilation is the default, may I endorse Henry's suggestion of making the 64 bit compilation the default on 64 bit OS.

Also a refence to setting the WM_64 macro in section 4 of the README file wouldn't go amiss.
gcollecutt is offline   Reply With Quote

Old   August 8, 2007, 02:02
Default Sorry Guys - I just found the
  #5
New Member
 
Greg Collecutt
Join Date: Mar 2009
Location: Brisbane, Queensland, Australia
Posts: 21
Rep Power: 8
gcollecutt is on a distinguished road
Sorry Guys - I just found the reference to WM_64 in the readme file - a bit further on than I had read to!

My Apologies.
gcollecutt is offline   Reply With Quote

Old   August 8, 2007, 03:43
Default We have never found running 64
  #6
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 13
henry is on a distinguished road
We have never found running 64bit much faster than 32bit but on some processors it is faster. Typically 64bit is faster than 32bit on AMD64/Opteron processors and on the latest 64bit Xeon processors but not on P4-EM64T processors. However, we expect all recent and future 64bit processors to provide better 64bit than 32bit performance so we will make the 64bit option the default for 64bit processors in the future.
henry is offline   Reply With Quote

Old   August 8, 2007, 04:40
Default Henry, changing from 32 bit to
  #7
New Member
 
Greg Collecutt
Join Date: Mar 2009
Location: Brisbane, Queensland, Australia
Posts: 21
Rep Power: 8
gcollecutt is on a distinguished road
Henry, changing from 32 bit to 64 bit on a P4-EM64T gave me a 70% increase in speed when running LS-Dyna double precision. I have noted that, for single precision code, there is little improvement going from 32 bit to 64 bit. Perhaps my observed speed improvement was more a quick of the f77 compiler.
gcollecutt is offline   Reply With Quote

Old   August 8, 2007, 04:51
Default My comments only relate to the
  #8
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 13
henry is on a distinguished road
My comments only relate to the performance of OpenFOAM on the machines we have at OpenCFD. We expected an increase in performance in using 64bit on our P4-EM64T machines but didn't get, but these are an early version of the P4-EM64T processor. We now have a Xeon 5160 machine on which we do get in increased performance when running 64bit but it is not anything like 70%.
henry is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
User-Defined Fan Socrate FLUENT 0 March 28, 2007 10:25
Hub Region Not Defined Flavio CFX 3 November 6, 2006 03:07
User Defined GUI Frederik FLUENT 0 June 23, 2006 16:12
What must be defined in fvSolution Marco Kupiainen (Kupiainen) OpenFOAM Running, Solving & CFD 1 February 21, 2005 06:03
multiply defined CMB CD-adapco 1 September 30, 2004 16:22


All times are GMT -4. The time now is 11:04.