[Wien] insufficient virtual memory

[Oleg Rubel]

Dear Hajar,

it will be easier to make a suggestion, if you can also provide some 
insight to the properties that you would like to capture. For now it is 
not clear why do you need hydrogen termination instead of taking 
advantage of the periodic boundary conditions (especially for graphene)?

Thank you
Oleg

On 11/06/2013 2:59 AM, Peter Blaha wrote:
> You did not tell us which hardware you are using.
>
> Eventually, you can do it if you make sure that you are running only
> ONE k-point on this machine; i.e. do not use k-parallelism (at least not
> on the same computer).
>
> PS: You want to simulate a single sheet of graphene. So why would you
> use more than ONE k-point in the z-direction (9x9x2) ????
>
> On 06/11/2013 07:54 AM, Hajar Nejati wrote:
>> dear Oleg
>> I mention the points that I think can be benefit to solve my problem:
>>
>> 1. The origin cell has these lattice constant: a=b=2.53 and c=15.0
>> Angstrom.
>> 2. 4×4×2 refer to the dimensions of supercell while the k-mesh is 24
>> k-points in irreducible Brillouin zone (9×9×2).
>> 3. I run lapw1 -nmat_only then I saw 14136 in case.nmat_only file (that
>> is greater than 10000). So I had to increase NMATMAX to 20000 and
>> compile wien2k again and rerun the scf calculation with lower RKMAX (=2).
>>
>> Is there any suggestion except considering a parallel MPI version? (I
>> use .machines file to do parallel calculation)
>> Thanks a lot, again.
>> Best Regards
>> Hajar
>>
>>
>> ------------------------------------------------------------------------
>> *From:* Oleg Rubel <orubel at lakeheadu.ca>
>> *To:* wien at zeus.theochem.tuwien.ac.at
>> *Sent:* Monday, June 10, 2013 1:17 PM
>> *Subject:* Re: [Wien] insufficient virtual memory
>>
>> Dear Hajar,
>>
>>  > I was trying to do a supercell calculation (hydrogenated
>> graphenewith 64
>>  > atoms) within 4×4×2.
>>
>> It is unlikely to run such a job on a single processor. You need to
>> consider a parallel MPI version (see Sec. 5.5 of the UG).
>>
>> Does 4×4×2 refer to the k-mesh? If yes, this is too dense. Most likely
>> you can go with a single k-point.
>>
>>  > When I run scf, this message appears:
>>  > Lapw0 end
>>  > severe (41): insufficient virtual memory
>>  > lapw1c unknown
>>  > lapw1c unknown
>>  > lapw1c unknown
>>  > (To be sure, I have searched all the previous emails on this topic,
>> but
>>  > failed to solve my problem.)
>>  > I know that RKMAX should be small and NMATMAX large (I increase
>> NMATMAX
>>  > from 10000 to 20000 and NUME to 1500). The scf runs without error
>>  > massage when I decrease RKMAX to 2, but the total energy NOT converge
>>  > (when I set RMT of H atoms to 0.6, the error remains).
>>
>> The purpose of NMATMAX is to prevent the calculation from crashing when
>> the matrix size increases. Wien2k does it by lowering the effective
>> RKmax, which you can find in the *scf file. However, changing NMATMAX is
>> not a solution for this problem.
>>
>> I would also suggest to reduce the disparity between RMTs as much as you
>> can.
>>
>> I hope this will help.
>>
>>
>> Best regards
>> Oleg
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>