[Wien] VLM's (very large matrices)

[Jorissen Kevin]

Thanks.  This is obviously true.  I was merely trying to make the best of our current configuration.
 
Thanks,
 
Kevin.
 

	-----Oorspronkelijk bericht----- 
	Van: Peter Blaha [mailto:pblaha at zeus.theochem.tuwien.ac.at] 
	Verzonden: do 7/1/2004 4:21 
	Aan: wien at zeus.theochem.tuwien.ac.at 
	CC: 
	Onderwerp: Re: [Wien] VLM's (very large matrices)
	
	

	Well, PCs come to some limit and sequential codes too.
	
	Such an example (if it really requires such large matrices ?) would be worth
	to try with the mpi-parallel version on a shared memory maschine.
	(I recommend to use at least 4 processors, because the mpi version will
	require twice as much memory)
	
	Of course I undestand that installing scalapack-pblas is not so simple,
	but that's the way to go.
	
	> Dear WIEN users,
	> I'm using the wien code compiled with ifc7 and statically linked with mkl6, and I'm trying to push nmatmax as far as it will go.  I get crashes (for real system, ie lapw1) above about nmatmax = 12500 (nume is set to 2000 - okay, for systems with few electrons I could gain a little there), corresponding to about 1.7 GB of memory used.  At higher values, I get allocation errors, though there is about twice that amount of RAM available.
	>
	> This appears to be a compiler limitation :  on http://support.intel.com/support/performancetools/fortran/linux/sb/CS-007795.htm we read that for IA32 the ifc does not allow arrays larger than 2 GB.
	> Documentation on the PGI website suggests the same thing will happen.
	>
	>
	> How do you work around this?
	> Thank you very much,
	>
	> Kevin.
	>
	>
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	                                      P.Blaha
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	Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
	Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
	Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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