VTST

[kambiz]

Dear All,

I tried to make my VASP 4.6 compatible with VTST codes. Now in my my main directory I have both "vasp" and "vasp_vtst" files. and I created a directory "vasp4.6/vtstcode" which contains :

neb.F, dynmat.F, dimer.F, lanczos.F, sd.F, cg.F, qm.F, lbfgs.F, bfgs.F, fire.F, opt.F, instanton.F, dynamic.F, dimer-save.F and chain.F

When I write: "strings vasp_vtst | grep NEB" this is the result:

NEB: the previous image is higher in energy: NEB: the next image is higher in energy : NEB: only prev energy greater NEB: only next energy greater NEB: image is at an extrema
NEB: diff energy (min, max): NEB: no climbing image found (3F13.5)neb.f
NEB: Tangent
NEB: forces: par spring, perp REAL, dneb
NEB: distance to prev, next image, angle between
NEB: projections on to tangent (spring, REAL)
Error reading item 'SPRING' from file INCAR. Error reading item 'LCLIMB' from file INCAR. Error reading item 'LTANGENTOLD' from file INCAR. Error reading item 'LDNEB' from file INCAR. L
Error reading item 'LDNEBORG' from file INCAR. Error reading item 'EFIRST' from file INCAR. ;FINCAR=#
Error reading item 'ELAST' from file INCAR. SPRINGLCLIMBLTANGENTOLDLDNEB(A5,A16,L7)LDNEBORGEFIRST(A5,A16,F14.6)NEB:ELASTneb.f
Error reading item 'FMAGFLAG' from file INCAR. ;FINCARFMAGVAL=#Error reading item 'FMAGVAL' from file INCAR. Must set EDIFFG < 0 when using IOPT > 0 CHAIN: Read ICHAIN CHAIN: Running the NEB CHAIN: Running the Dynamical Matrix CHAIN: Running the Dimer method CHAIN: Must set IOPT>0 to use the Dimer method CHAIN: Running the Lanczos method CHAIN: Must set IOPT>0 to use the Lanczos methodchain.f
electronic convergence detail LDIAGWEIMINEBREAKDEPERNRMMTIME


Anyone please tell me, is it OK?

Thanks
Kambiz

[graeme]

If those are strings from the vasp binary with our codes linked in, you should be good to go.

The instructions for linking, which you have probably already found, are here: http://theory.cm.utexas.edu/vtsttools/code/

Also, please post questions about vtstcode issues here, and not on the main vasp forum. They do not support methods such as the climbing image NEB.

[kambiz]

Thanks Dear Admin,

I should write " strings vasp_vtst | grep NEB ", to get information about new codes. I mean that I have two files in the main directory: "vasp" and "vasp_vtst" and so when I write

"strings vasp | grep NEB" there s no information.


I just wanna know that "vasp_vtst" and "vasp" files should be in one file or not.

Thanks

Kambiz

[graeme]

It sounds like you have two versions of vasp compiled, one with our vtstcode and the other without. That's fine.

By the way, to more clearly check to see if you have linked the vtstcode and which version you have, you can do:

strings vasp_binary | grep VTST

[kambiz]

Dear Admin, Thanks for your kindness,

when I use "strings vasp_vtst | grep VTST" the result is:

VTST: version 2.03d, (02/18/09)CHAIN: initializing optimizer ICHAIN

Is it OK?

And sorry again when I use "strings vasp_vtst | grep LCLIMB" it says:

Error reading item 'SPRING' from file INCAR. Error reading item 'LCLI
MB' from file INCAR. Error reading item 'LTANGENTOLD' from file INCAR. Error reading item 'LDNEB' from file INCAR. L
Error reading item 'ELAST' from file INCAR. SPRINGLCLIMBLTANGENTOLDLDNEB(A5,A16,L7)LDNEBORGEFIRST(A5,A16,F14.6)NEB:ELASTneb.f

So can I activate "LCLIMB" keyword in my INCAR from now on?

I really appreciate for your help

Kambiz

[graeme]

The strings command just extracts ascii from a binary file; since write the VTST version, you can find it in the executable this way.

Given that you see the VTST version, it is linked in and you can use all the tags that we provide, including LCLIMB to turn on the climbing image (which is on by default, by the way).

[kambiz]

Dear Admin,

I have another question which may seem so basic.

In NEB, POTIM = 0.0 (IBRION = 3) means that ions doesn't move, so how the whole band structure can be optimized in this case?

I want to use POTIM = 0.1, for whole calculation, is it fine?

Thanks a lot

Kambiz

[graeme]

Again, do not cross post to the main vasp forum. Questions about our code should only be posted here.

The use of ibrion=3 and potim=0 means that the built-in vasp optimizers will not move the atoms. Then, you can use ours if you wish. This is explained here:

http://theory.cm.utexas.edu/vtsttools/optimizers/

The appropriate choice of POTIM depends upon which optimizer you use and how far from convergence your images are. POTIM=0.1 is generally a small and safe value. Increasing it should improve convergence, but if you increase it too much you will find that an optimization can diverge.