[TCOD] Presenting TCOD at the IUCr 23rd Congress?

Mon Feb 10 14:16:09 UTC 2014

Dear Saulius and everyone else,

I'll be happy to join.

(I realize that people already have replied, sorry for not accounting for that, but I need to send this quickly now.)

One question back regarding your second question:
-- What are the existing quality criteria for COD? I know that I have to give Fabs, but that only applies if the data is not "old". However, data that is "old" (I forget the cutoff year) is still considered acceptable, so clearly it has been decided that the most important thing is not that a number is accurate but that an experienced person can see HOW accurate it is. 

I think that we should calibrate our mindsets to this "intermediately liberal" attitude and would prefer a rather liberal attitude when it comes to the pure convergence parameters as long as the most important ones are given. That would be (in addition to which code was used...) a description of the basis set (e.g. something like "400 eV" for a plane wave pseudopotential code or perhaps "tier 1" if you use FHI-AIMS), k-point set and the force/cell convergence criterion. Then we could have a rough classification resulting in a little green, yellow or red label for well, intermediately and poorly converged calculations. A major problem is that the choice of functional may not be as easily tagged as good or bad. There are a number of pointers that all of us in the business know, and of course we can collect these into a sort of heuristic. The modern thing would of course be to crosslink structures in TCOD with corresponding structures in COD and let some kind of neural network (or similar) generate a new heuristic free from our biases, although of course biased by only accounting for the crystal structure. 

Regards,
Torbjörn

P.S. 
OK, so maybe someone has to go first and get complained at by everoyne else for his sloppy standards... Here a suggestion for marking up the two most important convergence parameters: 
Max residual force on atoms < 0.01 eV/Å = good, 0.1-0.01 = intermediate, > 0.1 = low
K-point resolution < 0.2 Å^{-1} = good, 0.75-0.2 = intermediate, > 0.75 = low

There, I took the plunge, now to hide under my desk....
/T.B.

---
Torbjörn Björkman, PhD
COMP, Aalto University School of Science
Espoo, Finland

________________________________________
Från: tcod-bounces at lists.crystallography.net [tcod-bounces at lists.crystallography.net] för Saulius Gražulis [grazulis at ibt.lt]
Skickat: den 10 februari 2014 15:14
Till: tcod at lists.crystallography.net; blueobelisk-discuss at lists.sourceforge.net; Nicola Marzari; Peter Murray-Rust; Antanas Vaitkus; Andrius; Chateigner Daniel
Ämne: [TCOD] Presenting TCOD at the IUCr 23rd Congress?

Dear colleagues,

as I am going to the 23rd Congress of IUCr this year, I though that this
would be a good opportunity to present TCOD to crystallographic and
chemical community there.

Unfortunately, the deadline of abstract submission is tomorrow,
2014-02-11, so I need a short feedback from you ASAP... I apologize for
such a short notice.

At this stage, TCOD poster/talk is not to present some spectacular
results, but rather to inform community and to make sure that everyone
is invited, so that nobody is excluded. Only in this case will the TCOD
have its value.

I attach a project of an abstract and an author list. If you do not
mind, I present the abstract as a presenting author and thus put my name
first; otherwise the list is alphabetical. If the NWchem people, or
anyone else, would wish to participate and to provide their input about
computational data representation and ontologies, I'd be glad to include
them as co-authors. At the moment, I have included people on the tcod
mailing list (except that I do not know the full name of , and Peter and
Nicola with whom we discussed TCOD in detail; I hope you will
participate :).

Since we are a new team, I'll do as follows:

a) those who e-mail me till tomorrow (2014-02-11) that they participate
in the presentation I leave on the author list;

b) those people who do not agree or *do not reply* by 2014-02-11 I will
leave out as not consenting with their authorship;

c) If no one from the theoretical community replies, I'll probably
refrain from submitting the abstract.

d) If you join the team, I'll submit the abstract and the author list
tomorrow, on 2014-02-11.

Me, Andrius and Antanas will do all the technical editing of the poster
or slides; any comments on the text from you are welcome (but please
keep in mind that the abstract is limited to 2000 chars). The most
important contribution from you wold be the ideas:

-- how to describe the computation data so that it is useful and
reusable (what parameters need to be specified for different methods)?

-- what quality criteria do we want to put on structures in TCOD (and in
general on published DFT and other structures)? In other words, what
computed structures will we be happy with?

After the abstract submission we will have some time to polish TCOD
policy details, data dictionaries (initial version can be found here:
http://www.crystallography.net/tcod/cif/dictionaries/) and software
pipeline (we will take care of this last bit in Vilnius, but
participants are welcome :).

Regards,
Saulius

--
Dr. Saulius Gražulis
Vilnius University Institute of Biotechnology, Graiciuno 8
LT-02241 Vilnius, Lietuva (Lithuania)
fax: (+370-5)-2602116 / phone (office): (+370-5)-2602556
mobile: (+370-684)-49802, (+370-614)-36366