[Q-e-developers] Summary of the QE developers meeting

[Paolo Giannozzi]

Summary of Quantum ESPRESSO (QE) Developers' Meeting
Trieste 12/1/2011

Participants:
1- Paolo Giannozzi
2- Layla Martin-Samos
3- Stefano de Gironcoli
4- Riccardo Sabatini
5- Andrea Dal Corso
6- Tone Kokalj
7- Nicola Varini
8- Giovanni Bussi
9- Sandro Massidda
10 Marco Monni
11 Emine Kukucbenli
12 Alessandro Laio
13 Feliciano Giustino
14 Ralph Genbauer
15 Nicola Marzari
16 Stefano Fabris
17 Andrea Ferretti
18 Simone Piccinin

(Missing: SB, CC, DC, LP. FM, MCal)

PG introduces the main topics that will be discussed:
1) Establishment of a QE Foundation
2) QE modularization and packaging
3) Various Verification and Validation initiatives
4) The Moka builder and transition to XML input and output

----------------------------------------------------------
1) QE Foundation
RS explains the goals of the foundation:
- keep QE domain names and trademarks (name, symbol, etc)
- become the recipient of donations from users (if any) and
   from other institutions (e.g. for QE tutorials)
- apply for EU grants, spend the available money (if any)
   without the constraints and the bureaucracy affecting
   universities and public research centers.
Many serious open-source projects have an associated foundation
or the like. The consulting company in Udine we have contacted
(Conecta: services related to open-source software) is very
positive on this and advises UK as a convenient place, since
establishing and maintaining it is quick, simple, relatively
cheap. Once the foundation is established, we can apply for
"charity" status, yielding fiscal advantages (but it must be
no-profit and stricty limited to its stated goal). The most
immediate task is to write down the statute.
During the discussion, NM suggests to specify a method by
which current members have ways to participate during the
admission of new members.

----------------------------------------------------------

2) QE MODULARIZATION AND PACKAGING (Layla):
i. Current status: packages, plugins, libraries, etc.
- External/independent libraries (with their own development
   environment, release time ...) like lapack, blas, iotk are in a
   .tar.gz form inside extlibs. They have been downloaded from their
   "official site" in their last release. The installation procedure
   is controlled by QE configure and Makefiles.
- External/independent "post-processing like" packages (WanT, YAMBO,
   Wannier90) are in a .tar.gz form inside dir archive. They have been
   downloaded from their official web site (no more cvs replicas as it
   was the case for Wannier90 in the past). The installation procedure
   is controlled by QE configure and Makefiles that, if available, run
   the package configure passing the already identified arguments such
   as the lapack path, compiler,.... For reaching the same portability
   as pw, ph .. however some effort has to be done in ensuring a better
   arguments compatibility between configure's.
- The question of distributing packages that need some PW/PH/CPV
   routines is still an open issue, mainly due to the fact that QE core
   routines are still in daily movement! suggestions on how to maintain
   compatibility, to simplify synchronization etc are really welcome.

ii. Current and future work on modularization and directory
    (re-)organization
- We are working on how to manage plug-ins as PLUMED (for
   metadynamics) and the call to DFT engine from other codes as for
   the NEB case. We are slowly reaching "convergence" and in (very)
   few weeks we will be able to propose a solution that is "portable"
   and minimizes maintainance and synchronization operations.
- For version 5.0 we propose to change the directory structure
   moving to something more "distribution like": each module/dir in
   espresso will have the following structure
                         DIR
                              src
                              doc
                              examples
                              tests
                              bin
   see GWW and TDDFPT module that already follow a similar structure.
   This will simplify the download of a customized release and simplify
   the search of examples and doc.

iii. Web interface for "intelligent" QE download
- We are working in a web interface for giving the users the
   possibility of downloading a customized release. We are also
   thinking of changing completely the web page, as it should
   reflect much better the distribution character of ESPRESSO.

iv.  binary distributions?
- volunteers sought!

v. a maintainer for each package?
- It would simplify the coordination of ESPRESSO (improving the
   communication with users too), if we could define a "coordinator"
   for each package. Meetings (or at least skype meetings) among
   coordinators should be regular and relatively frequent.

- Following the proposal of N. Marzari, we need to find a way of being
   all informed about current and future developments, who is doing  
what,
   money .... Suggestions are welcome.
   [ see http://www.quantum-espresso.org/wiki/index.php/Projects
     for a first attempt to collect info on what is going on ]
   However in the meanwhile we invite all of you to subscribe to the
   developers mailing list: http://qe-forge.org/mail/?group_id=10
   and start to send information about current and future developments,
   open positions, whatever you think could be relevant for improving  
QE.

----------------------------------------------------------

3) Verification and Validation (V&V), Pseudopotentials (PP)
The state of V&V in DFT/PW-PP codes is rather questionable wrt what
has been achieved in other fields. There are a number of V&V
initiatives already started or starting soon:
- Cecam (PG will follow this)
- A pre-proposal for a EU project (submitted); one of the participants
   (V. Blum) will visit Trieste soon (SdG is following this aspect)
- The "IOM startup" project (submitted): this is aimed at verifying
   the quality of PP by comparing with all-electron calculations,
   to be performed by the IOM unit in Cagliari. NM reports on more
   work he and collaborators are currently doing on PP/AE comparison.
----------------------------------------------------------

4) Moka builder, new XML I/O
RS present the status of the Moka structure builder and job submitter.
He also explains the need for a more structured QE input and output,
based on XML, so as to streamline production of input data, job
submission and retrieval of info from output. In the following
discussion, TK argues that we should not get rid of the possibility
to produce input by simply editing a file with vi and that XML has
a heavy and baroque syntax. He suggests considering a "simplified"
input of the form "keyword followed by value" instead of using the
full <markup option='value'> ... </markup> syntax.

[ note by PG: later I heard other unfavorable opinions on the XML
   input. I wonder if it isn't wiser to postpone the new XML input
   and finish first the XML output. This could also be an opportunity
   to make some serious and much-needed cleaning and documentation work
   on the XML output, and to provide more tools to extract data from
   XML output: something like the pw_export tools by AF, that
   unfortunately was never really integrated with the rest of the
   distribution, so it becomes quickly outdated ]
Pania:~/Work/Espresso$

---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222