CFD Online URL
[Sponsors]
Home > Forums > FLUENT

Memory allocation problem

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

Like Tree1Likes
  • 1 Post By Ammar Abdilghanie

Reply
 
LinkBack Thread Tools Display Modes
Old   February 15, 2007, 14:10
Default Memory allocation problem
  #1
Ammar Abdilghanie
Guest
 
Posts: n/a
I am trying to run Fluent in parallel and test the speedup which I get out of the parallelization. I have been able to estimate the speed up for a grid of about 64^3 cells. now I am expecting the speedup to be better for the finer grid (~122^3 cells) but my problem is that I can not estimate the run time on a serial machine for this grid as the simulation fails after one iteration because of memory problems. I also have to mention that I could not adapt the 64^3 grid to ~122^3 grid on the serial machine due to the same problem with memory, so I refined the grid on two CPU's and then read the refined grid into the serial machine but as I said it crashed right away..so the question is; is there a way of increasing the amount of memory allocated for Fluent simulation? I do not use the Sun utility (SGE) and we do not have batch scheduler..etc I saw thru few websites that some people specify the memory allocation in the batch script or thru the SGE utility.. so any input on this issue will be highly appreciated...
Nikolopoulos likes this.
  Reply With Quote

Old   February 16, 2007, 12:50
Default Re: Memory allocation problem
  #2
ejaz benchot
Guest
 
Posts: n/a
please read the Fluent manuals
  Reply With Quote

Old   February 16, 2007, 13:04
Default Re: Memory allocation problem
  #3
Ammar Abdilghanie
Guest
 
Posts: n/a
I kinda skimmed through the manual and could not locate this information. so if you know which section talks about this issue pls let me know. thanks for your reply

  Reply With Quote

Old   February 16, 2007, 17:10
Default Re: Memory allocation problem
  #4
rj
Guest
 
Posts: n/a
Make sure you have enough memory on the machine. Depending on the platforms you are using, on lnamd64, you may expect around 1GB memory per 1 million cells for single precision.
  Reply With Quote

Old   February 17, 2007, 00:27
Default Re: Memory allocation problem
  #5
ammar
Guest
 
Posts: n/a
thanks for your response. the machine has about 4 GB of memory. if I use top command during the simulation I find that I am only using 10% of them. If I selected Grid/info/memory usage in Fluent, it shows that I need about 2 GB of memory for the simulation, so I need to devote about 50% of the available memory for my simulation. I am a new linux user and I donnu how to do this. thanks alot

  Reply With Quote

Old   February 19, 2007, 19:15
Default Re: Memory allocation problem
  #6
rj
Guest
 
Posts: n/a
What you have sound sufficient for the case. Can you post the error message here? In any case, if you want to study the speedup, you can always run with -t1 for the single-processor performance. What verion of Fluent are you using? Have contacted your Fluent support?
  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
memory allocation error MAB CFX 14 Yesterday 20:26
Help understanding Memory Allocation Factor Todd CFX 1 March 6, 2008 14:27
RAM memory problem alpha Main CFD Forum 8 February 12, 2008 12:07
Relative Speed and Memory Allocation Kramer CFX 3 August 9, 2005 11:58
memory problem wilson CFX 6 March 30, 2005 18:34


All times are GMT -4. The time now is 21:58.