Out of mesh memory

edodo

Hi,

I don't really have a solution to this problem, but I can offer an
idea of where the trouble might be and where you might start trying to
fix it.

The problem might be with what you are trying to mesh. Are you meshing
an object that is very thin? For example a solenoid is a long object,
but the thickness of the material is small, so it takes a lot of
memory to mesh it.

According to the femlab support people the memory thing in the corner
of the femlab screen is telling you about how much memory the
graphical user interface (GUI) is using compared to how much is
allocated to the GUI. It has nothing to do with the memory usage of
calculations.  

I am constantly running into memory problems myself. I'm running a
computer with 2Gb of RAM as well. Are you running femlab in windows?
Have you looked at the task manager to see how much virtual memory
femlab is actually using? I think in windows it doesn't always go up
to its maximum capacity. I've changed my operating system to linux,
which seems to use all the memory available, but I still get out of
memory messages sometimes.

Is there some symmetry in your model that you could use to simplify it
and reduce the mesh?

Regards,
Jennie

edodo

Some other general remark about "Out of Memory" problems.

In my experience with the Femlab 2.3 version, I have noticed that after such an error occurred, the memory management of the MatLab process is corrupted, and the available memory has reduced, so new errors tend to appear sooner.

The only solution seems to be, to close the MatLab process and start a new Matlab process.
Although I never tested this for the FemLab 3 version, I assume that this might still be a useful thing to do after an "Out of Memory" error has occurred.

Anyway, remains the fact that these memory errors are very annoying. Hopefully this will receive attention of the Femlab developers.

Regards, Frits.


Yahoo

edodo

Hi,
It is nice to have chat with Femlab users.
About out of memory, we can pick up the answer from the website as follows:



"Out of memory", why do I get this message?

Especially in 3D modelling, extensive memory usage urges some extra precautions. The "Out of Memory"-problem occurs whenever FEMLAB tries to allocate an array which does not fit sequentially in memory. It is common that the amount of available memory seems large enough for the array - but there may exist no continuous block of that size, due to fragmentation. If you for example look in the task manager of Windows, this may have the effect that you can't see any high memory allocation, and get "out of memory" anyway.
The "Memory Usage" column in the Windows task manager can also be misleading, because it only shows the currently swapped portion. A better indicator of total usage can be found like this (Win2000, WinNT, Win XP):

Press Ctrl-Alt-Del to bring up the Task Manager.
Go to the "processes" tab.
From the View menu, choose Select Columns.
Select the Virtual Memory Size check box.
Now find the javaw.exe process that corresponds to the FEMLAB process in the process list and look in the "VM Size" column. This shows a better value on the actual memory used.
I hope this will give you help.

rgrds,

Hady

edodo

>From what I have seen MS Windows seems completely unable to reorganise
its memory as it gets full which means that if an application or library
gets planted in the middle of memory then other applications can only
allocate half the available memory as the blocks have to be contiguous.

Linux reorganises its memory which means you can keep using memory until
swap and real memory are full (although as soon as you start using swap
things will slow down horribly due to the comparitive access times of
RAM and hard disk.)

Also I don't think this is unique to Linux, I think most of the other
unixes (unices?) behave the same.

As far as processing speed is concerned, I have found that subjectively,
Linux is faster, but not by much.

Regards,

Alex