CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Relative Speed and Memory Allocation

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 30, 2005, 11:24
Default Relative Speed and Memory Allocation
  #1
Kramer
Guest
 
Posts: n/a
Hi everyone,

i am trying to start a simulation with 4 Million Hexas (3 Domains) using 3 Computers (Windows XP, 2GB RAM). The computers have different speeds, so in the host.ccl three different relative speeds are set. Now when i start the solver, it seems like the solver tries to allocate memory with the same factors like in the host.ccl. The problem is that in this case not enough memory is available. Is there a way to force the solver to allocate on all computers the maximum memory, because otherwise the simulation stops with a not enough memory error.

Thanks Kramer
  Reply With Quote

Old   June 30, 2005, 15:05
Default Re: Relative Speed and Memory Allocation
  #2
James Date
Guest
 
Posts: n/a
I think what you're basically saying is that the fastest computer is being allocated more than 2GB of memory, hence the simulation stops with a memory error. The only way to get around this is to make all the computer speeds the same in the hosts.ccl file. This will result in equal partitioning for each computer and hopefully overcome the memory error since each computer will be allocated a partition which takes less then 2GB's of memory to solve. However, you will not get good parallel speed up doing this, since and the solution will be heavily dependent on the speed of the slowest computer! How about just having a few more PC's in your cluster, with the correct speeds set in the host.ccl file, this will lower the memory requirement for each PC. You should be able to run your 4,000,000 hex problem on 4 PC's using single precision without any issues.
  Reply With Quote

Old   July 3, 2005, 20:39
Default Re: Relative Speed and Memory Allocation
  #3
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Is the simulation stopping in the solver or the partitioner? If the simulation is stopping in the partitioner then simply using another partitioning algorithm will help.

Glenn Horrocks
  Reply With Quote

Old   August 9, 2005, 11:58
Default Re: Relative Speed and Memory Allocation
  #4
Angelina
Guest
 
Posts: n/a
Bank Darlehn Info Banken Geld Berechnen Schweizerkredit Konto Privatdarlehen Schufafreie Kredite in bar Kreditvermittlung
  Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Memory bandwidth vs number of GB BrainPop Hardware 2 August 22, 2011 02:40
Concentric tube heat exchanger (Air-Water) Young CFX 5 October 7, 2008 00:17
Memory allocation problem Ammar Abdilghanie FLUENT 5 February 19, 2007 19:15
Memory size on disk, help! Pah FLUENT 2 August 30, 2005 23:30
Comparison of F90 and F77 in terms of running speed X. Ye Main CFD Forum 15 November 12, 1999 16:57


All times are GMT -4. The time now is 17:21.