[Wien] insufficient virtual memory

[Oleg Rubel]

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