[Wien] mbj on Diamond

[Saeid Jalali]

Dear Peter,
I compared it with the last original brj.f. You really made substantial changes. Thank you very much for your nice effort on brj.f.

I recompiled the lapw0 replacing your new brj.f file. But, unfortunately, our case stopped at the first cycle with the following error in lapw0: 

 LAPW0 END
forrtl: severe (174): SIGSEGV, segmentation fault occurred
Image              PC                Routine            Line        Source             
lapw0              000000000040AA28  brj_                       46  brj.f
lapw0              0000000000479D44  vxclm2_                   534  vxclm2.f
lapw0              0000000000482859  xcpot1_                   365  xcpot1.f
lapw0              000000000043A7D7  MAIN__                   1696  lapw0.F
lapw0              0000000000403D3C  Unknown               Unknown  Unknown
libc.so.6          000000350A41EB1D  Unknown               Unknown  Unknown
lapw0              0000000000403C39  Unknown               Unknown  Unknown

We run the mbj for diamond, and found that the problem is not only for our case. It stops with the above error for any other simple cases.

I again copied the old brj.f and recompile the lapw0, and fond that it works properly for the diamond and the other simple cases, but for our case.

Any comments will be highly appreciated.
Thank you again,
With my best regards for you,
Saeid.





--- On Fri, 10/15/10, Peter Blaha <pblaha at theochem.tuwien.ac.at> wrote:

From: Peter Blaha <pblaha at theochem.tuwien.ac.at>
Subject: Re: [Wien] mbj on Diamond
To: "A Mailing list for WIEN2k users" <wien at zeus.theochem.tuwien.ac.at>
Date: Friday, October 15, 2010, 4:38 AM

Hi,
After I got the struct file, I could verify the problem.

As expected, it is again in the SRC_lapw0/brj.f subroutine,
where one has to find the root of a function.

For strange densities this is numerically non-trivial.

The problem at the nucleus of heavy elements was solved before, but
here is the problem in the interstitial, when rho is very small and
also grad-rho, tau and laplace-rho are sufficiently small.

Then the required functions are "nearly" zero (lt. 10^-6) for a range
of x=10-30; but using x=30 produces a V-xc potential of -100 Ry,
which is the reason for your "Eigenvalues below zero".

When such problems occur again, please check also case.output0.
The Fourier coefficients of Vxc must "converge", i.e. (0 0 0) should be
order one, while (0 0 30) should be order 10^-5 .

The attached subroutine brj.f should fix these problems (at least your case converges
smoothly).

Dear All,



We are performing the mbj calculations for a carbon based compound. According to the usersguide there are three SCF cycles for mbj calculations: first a regular calculations within LDA/GGA (we use the PBE-GGA here),  second one more cycle run_lapw –NI –i 1 , and third the mbj run after changing the potential energy functional indxc=28 in case.in0 and index=50 in case.in0_grr.

Here we call the regular SCF cycles C1.scf, second one-more SCF cycle as C2.scf, and the third the mbj as cycle C3.scf.

The first regular cycle and the second run_lapw –NI –i 1 are converged smoothly. However, the third mbj cycle is stopped at lapw2 in its second iteration.

We analyzed the problem to find the source of the error. The result is given below, where the C2.scf line refers to the last :ITE of the second one more SCF cycle, and the C3.scf refers to the first :ITE of the third mbj run:



C2.scf::NTO033: TOTAL   CHARGE IN SPHERE  1 =        3.9781366

C3.scf::NTO033: TOTAL   CHARGE IN SPHERE  1 =        2.4250427



C2.scf::CTO033: TOTAL   CHARGE IN SPHERE  1 =        3.9781254

C3.scf::CTO033: TOTAL   CHARGE IN SPHERE  1 =        3.9470631



C2.scf::DIS  :  CHARGE DISTANCE       ( 0.0000355 for atom   33 spin 1)      0.0000136

C3.scf::DIS  :  CHARGE DISTANCE       ( 1.8978668 for atom   25 spin 1)      1.5016586



C2.scf::NEC01: NUCLEAR AND ELECTRONIC CHARGE    366.00000   365.98257     1.00005

C3.scf::NEC01: NUCLEAR AND ELECTRONIC CHARGE    366.00000   365.98171     1.00005



C2.scf::FER  : F E R M I - ENERGY(TETRAH.M.)=   0.21390

C3.scf::FER  : F E R M I - ENERGY(TETRAH.M.)=  -1.44751



The result clearly shows that there is a jump in :NTO, :DIS, and :FER (But in :CTO) after changing the functional to index=28.



-- 
                                      P.Blaha
--------------------------------------------------------------------------
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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