Large Arrays/Commons

[Toon Moene]

plischke@isam.de wrote:

> eventually somebody can help (or tell me that there is no solution):
> 
> - I have a rather complex finite element code (to be compiled with g77)
>   and would like to run
>   a bigger model than previously. I have however problems in using
>   sufficiently large arrays.
>   I split the large arrays into three COMMON BLOCKS, e.g.
>   COMMON /A(50000000)
>   COMMON /SOL1/ B(28000000)
>   COMMON /SOL2/ C(56000000)
>   with  IMPLICIT REAL*8 (A-H,O-Z)
>  I can compile and link without problems,
>  but get a segment violation at excution (immediately, and also if
>  a use just a main program for storage allocation (i.e. don't call
>  any subroutines)
>  I suppose that the maximum storage to be allocated is limited by the
>  physical memory of my PC (1 GB), because there are no problems as long
>  as the sum of all allocated storage is araound 900 MB. 
>  Is there any solution?
>  Do you need more information?

Well, actually, we do (for instance, what operating system are you using 
on this PC?  Windows, DOS, Linux, {Free|Net|Open}BSD, etc. ;-)

However, I'll cut you a deal: The problem you see is most probably 
caused by the fact that on Linux, shared libraries are assigned memory 
addresses from 2**30 onwards, i.e., at about 1 Gbyte.

If you compile and link your program statically, i.e., using the option 
-static, you should be OK.

The maximum amount of memory you can use is the sum of RAM and SWAP sizes.

Hope this helps,

-- 
Toon Moene - mailto:toon@moene.indiv.nluug.nl - phoneto: +31 346 214290
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