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Fluent - Out of Memory Error

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Old   July 20, 2007, 05:21
Default Fluent - Out of Memory Error
  #1
asd
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i get a 'out of memory.malloc_storage: unable to malloc Density' errors when i initiliaze my domain for computation in fluent. Any ideas??

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Old   July 20, 2007, 11:01
Default Re: Fluent - Out of Memory Error
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Ben
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Surely you have answered your own question...
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Old   July 20, 2007, 11:41
Default Re: Fluent - Out of Memory Error
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NewtonUSP
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Ben, I don't know if it is the problem, because here I had the same problem with version 6.3 of fluent in a system with a lot of memory avaliable. But when I choose to run the parallelized version of fluent, in the same system, the memory issue disappears. Have any ideas??? Does Fluent have memory limitations runing in serial mode??

Thanks...
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Old   July 20, 2007, 19:12
Default Re: Fluent - Out of Memory Error
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Ahmed
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Are you running on a Windows os? Switch to Linux
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Old   July 20, 2007, 20:10
Default Re: Fluent - Out of Memory Error
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NewtonUSP
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Yeap... I thought it was a windows problem... but I had the same problem in a linux cluster... so... It maight be an Ansys problem, cause in the 6.2 version of fluent, this problem does not happens...
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Old   July 20, 2007, 20:29
Default Re: Fluent - Out of Memory Error
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Ahmed
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the function malloc (see any book on the C language) requests from the operating system to reserve and assign a memory block, if the os fails to assign this block of memory you get this message. The memory need not be real, virtual memory is OK too. As you see, this is os problem
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Old   July 21, 2007, 00:57
Default Re: Fluent - Out of Memory Error
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asd
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Ben..the question was put fwd becuase it was hard to belive that memory would be an issue given that the system has 2GB RAM and over 120GB of disk space....as others have correctly pointed out, its an issue with the OS.
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Old   July 21, 2007, 09:02
Default Re: Fluent - Out of Memory Error
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NewtonUSP
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Yes, I though it was a OS problem too... But it is very interesting that this problem, for me, only appers when runing the serial version of fluent. As I said before, when it is parallel, in the same machine (SMP), this problem goes away, in both windows and Linux systems...
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Old   July 21, 2007, 17:47
Default Re: Fluent - Out of Memory Error
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Ahmed
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Computers use two types of memory:- 1- RAM or actual physical memory chips installed 2- Virtual Memory, a sector of the hard disk that is reserved by the operating system in case the physical memory is totaly used and there is still need for more. To pinpoint what exactly is happening in your case, well, not easy, any way I will give you some pointers that might help (They are not ordered logically)

A- If your IT guy is smart and diligent he/she might be able to install more RAM or he/she can fine tune the maximum virtual memory size allocated by your computer OS or he/she can upgrade your computer graphic card to a one with (More Installed RAM) that will relieve more virtual memory for your programme.

B- Here is what you can do

1- Do you have time to remesh your problem, if so do the following: reduce the number of cells outside the boundary layers (unless the rate of strain tensor is high) these cells are not needed in excess 2- What solver are you using The segregated or coupled one The coupled solver uses more memory. 3- If your wallet is in good shape, you can always buy a CRAY, SG.....

There are two more minor factors that might affect your problem, but I need to have the full picture before me, Only you can decide to see if changing the discretization scheme or order will affect the quality of the results of your analysis.

Wish you good luck.

NewtonUSP: when your computer is running two or more processors, each require its own virtual memory space
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