memory usage of code compiled with gcc 3.2

Andrea 'Fyre Wyzard' Bocci fwyzard@inwind.it
Fri Dec 27 20:07:00 GMT 2002


At 10.54 27/12/2002 -0300, hektor monteiro x285 wrote:

>Hi everyone! I am working with an astrophysical code that uses a lot of 
>memory (RAM). Basically because of a 3D matrix that I have to define. I 
>was working with 1G  of RAM before and could run the code with a cube of 
>70^3 cells. Recently I bought a new super machine with 4g of RAM and I am 
>using the gcc 3.2 compiler on linux redhat 7.3. But I am not able to run 
>more than 70^3 cells on this. Can anyone give me some clue?? I would think 
>I should be able to do better no? Is this a linux kernel limitation or gcc 
>or something else??
>
>cheers,
>
>Hektor

Hi Hector.
Actually, there are limitations on the size arrays con have with GCC, but I 
don't think you've stumbled in that. A 70*70*70 array is 343000 cells; 
using doubles, that'd amount to little over 2.6 MB. I think up to arrays of 
500*500*500 doubles you should have no problem (apart from exausting RAM, 
that is :-).

So, could you be a little more specific on what "I am not able to run more 
than 70^3 cells" means ? Do you get errors at compile time, or run time ? 
And, especially at runtimewhat kind of errors ?

fwyzard 




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