Welcome, Guest
Username: Password: Remember me
Forgot your password? Forgot your username? Create an account
Forum
Installation
Windows Version
DIfference beetween 32 and 64bits
Flat Threaded

TOPIC: DIfference beetween 32 and 64bits

DIfference beetween 32 and 64bits 12 years 3 months ago #5154

  • AlexV
  • AlexV's Avatar
I had success to set up Telemac with parallel processing on my W7 64bits computer :cheer: , but i still have no clue why the instalation is not working in 64 bits :( .

Anyway what differences are there beetween a 32bits set up and a 64bits one ?

Understand my question as "is it worth i spend time to configure a working 64bits setup or not".

Thanks.
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5156

  • a.weisgerber
  • a.weisgerber's Avatar
Hello

In practical use the main difference between a 32bit and a 64 bit application is the quantity of memory it can use. A 32bit system is limited to 4GB of memory while a 64bit system can go much beyond.

Both 32bit and 64bit applications can be used on a 64bit system, but only 32bit applications can be used on a 32bit system.

Gradually 32bit will be abandoned and everything will be in 64 bit, but in practice this will still take a few years to take place.

So as long as you are not limited by memory I don’t think you should worry about using the 32bit version if it works for you. But bear in mind that sometime in the future only 64bit will be available.
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5159

  • jmhervouet
  • jmhervouet's Avatar
Hello,

I would add that the computer time may be very different, perhaps about half the time in 64 bits compared to 32 bits, am I wrong ?

JMH
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5160

  • c.coulet
  • c.coulet's Avatar
  • OFFLINE
  • Moderator
  • Posts: 3722
  • Thank you received: 1031
Hi
Sorry jean-Michel but for me you're wrong!
There is probably a speed-up when switching from 32 bits to 64 bits but the ratio is not 0.5
The exchanges between memory and processor are probably divided by 2 but the processor instructions are the same at the same speed.
As TELEMAC is not so large in memory (for reasonable models) so this is the processor which is dominant for the computing time.

Maybe we could try to make a test after the release of 6.2 version...

Regards
Christophe
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5162

  • jmhervouet
  • jmhervouet's Avatar
Hello Christophe,

I thought that operations like addition or multiplication have such a speed-up when you move to 64 bits because double precision becomes the normal numbers, and are treated with the same clock than single precision in 32 bits. I may be wrong but we did have a speed-up of 2 when a Linux 64 bits replaced a Linux 32 bits on our HP machines which were 64 bits from the origin.

JMH
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5171

  • a.weisgerber
  • a.weisgerber's Avatar
Like Christophe, I am surprised that a doubling of performance is achieved by going from 32bit to 64bit. What I read in the past is that the gain (being able to use natively double precision variables) is compensated by the fact that all other variables not requiring double precision also take more space in memory. But this was not related to scientific applications.

It may be that for a scientific application where the majority of variables are in double precision, 64bit offers greater advantage.

On the same machine we already noticed a significant gain by running TELEMAC on Linux rather than Windows. As Christophe mentions it would be good to run a benchmark 32bit vs. 64bit with v6p2.
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5215

  • AlexV
  • AlexV's Avatar
Il will make a benchmark to tell the forum when (if !) i succed to install my intel64 fortran compiler.


I did try again and end up with the 32bits intel command line working but tnot the 64 bits.

I have this error message :
"visual studio not find in the system".

Si i try this :
[url http://software.intel.com/en-us/articles/error-visual-studio-2005-2008-or-2010-is-not-found-in-the-system-when-launching-command-prompt-from-start-menu/]LINK[/url]

And finally get this error :
C:\Windows\System32>"C:\Program Files (x86)\Intel\ComposerXE-2011\bin\compilerva
rs_arch.bat" intel64 vs2010

Intel(R) Parallel Studio XE 2011
Copyright (C) 1985-2011 Intel Corporation. All rights reserved.
Intel(R) Composer XE 2011 Update 5 (package 221)
Unknown command-line switch: amd64
Usage: "Setenv [/Debug | /Release][/x86 | /x64 | /ia64][/vista | /xp | /2003 | /
2008 | /win7][-h | /?]"

                /Debug   - Create a Debug configuration build environment
                /Release - Create a Release configuration build environment
                /x86     - Create 32-bit x86 applications
                /x64     - Create 64-bit x64 applications
                /ia64    - Create 64-bit ia64 applications
                /vista   - Windows Vista applications
                /xp      - Create Windows XP SP2 applications
                /2003    - Create Windows Server 2003 applications
                /2008    - Create Windows Server 2008 or Vista SP1 applications
                /win7    - Create Windows 7 applications

Note:
* Platform(x86/x64/ia64) and PlatformToolSet(v90/v100/WindowsSDK7.1) set in proj
ect or solution will override the environment
* To upgrade VC6 or later projects to VC2010 format use the VCUpgrade.exe tool.

"amd64" is a paramater for the architecture of the processor.

Any help will be appreciated even if it's not a telemac system issue.
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5216

  • AlexV
  • AlexV's Avatar
Good news and bad news.

I succeded to have a working intel fortran 64bits compiler. I can compile stem in scalar mode.

Now when i compile the whole telemac system, i have the "crt64.lib" issue. I get the file from the pre-compiled telemac system on the download section and put it on my SVN installation but it's still not working.

I've read that you can compile telemac in 64bits and partel in 32bits separatly and that it works. But i have no idea how to do that. I did have a look at the python script but i just can't read it.
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5217

  • c.coulet
  • c.coulet's Avatar
  • OFFLINE
  • Moderator
  • Posts: 3722
  • Thank you received: 1031
Hi
crt64.lib is just required for the parallel library and more particularly for the compilation of partel.
You should place the lib file in the target directory and it will works...

Hope this helps
Christophe
The administrator has disabled public write access.

Re: DIfference beetween 32 and 64bits 12 years 3 months ago #5218

  • c.coulet
  • c.coulet's Avatar
  • OFFLINE
  • Moderator
  • Posts: 3722
  • Thank you received: 1031
To come back on the performance of 32 and 64 bits, and particularly on hte last message of Jean-Michel, I think the results could probably due to a full switch from 32 to 64 bits (OS + Telemac!). In my mind we just deal with the telemac compilation so with the 32 or 64 bits version of TELEMAC running on a 64 bits architecture.
In such case, the 32 bits program runs well on 64 bits architecture but the computing time is quite similar to to the 64 bits version.

Hope this will clarify this point of the discussion.
Christophe
The administrator has disabled public write access.
Flat Threaded
Moderators: borisb
Forum
Installation
Windows Version
DIfference beetween 32 and 64bits

The open TELEMAC-MASCARET template for Joomla!2.5, the HTML 4 version.