[Q-e-developers] Next Quantum ESPRESSO release -- June 20th

[Paolo Giannozzi]

This is a rather complex issue and I am not sure it can be solved in the
next few days. If I understand correctly,
3D-RISM-SCF modifies the way the self-consistent code works internally, by
adding computation of additional
quantities inside the self-consistent loop. Until now this kind of changes
has been added inside QE directly by
the author, but after many uncoordinated additions the result has become a
mess. One idea that has been around
for a while is to locate some "hooks" in the code where additional
computations can be confined; then release the
implementation of additional methods (like 3D-RISM-SCF) as "add-ons" that
modify QE in those specific points only
(notice the plugins_* subroutines). Unfortunately this is still ongoing (or
maybe "notgoing") work.

My suggestion for the next release is to align 3D-RISM-SCF to the QE
version that will be released (this should be easy);
to release 3D-RISM-SCF as a modified QE (not yet sure how in practice, if
as a patch, or as a bunch of modified routines,
or as new PW/src and Modules/ directories); then, to start seriously to
think at how to merge it into QE.
Unfortunately, merging takes a lot of time and nobody is really in charge
of it (in the future this may change, hopefully).

About "custom" FFTs: these are used only in hybrid calculations, to speed
up the computation of (V_x\psi)(r) using FFTs
with a grid corresponding to a reduced cutoff (this is 1-2 times ecutwfc,
the cutoff for plane waves used in the expansion of \psi(r)=\sum_G\psi(G)
e^{iGr}, instead of 4*ecutwfc, needed in principle to perform the exact
computation). I am surprised
to hear that this is used in 3D-RISM-SCF (or are you planning to use them
in the future)?

Paolo

On Mon, Jun 8, 2015 at 3:38 PM, Filippo Spiga <spiga.filippo at gmail.com>
wrote:

> Dear Satomichi,
>
> thank you very much for your quick feedback. I will attempt myself to
> merge your branch into a local copy of current QE codebase and run the
> tests. If I get something weird, I will contact you directly. I suggest to
> sync by email again beginning next week, I will get in touch privately.
> From my perspective, once the code compiles and is aligned and test are
> provided then it can be released. I let senior QE developers and PIs
> comment further.
>
> Thank you to contributing to Quantum ESPRESSO, your effort is really
> appreciated!
>
> Regards,
> Filippo
>
> On Jun 8, 2015, at 1:02 PM, nisihara225 at gmail.com wrote:
> > Dear Dr. Filippo Spiga,
> >
> > the answers to your questions are as follows.
> >
> > > Which QE version is compatible with it?
> > The branch of 3D-RISM-SCF is compatible with the Q.E. 5.1.2.
> > In more detail, it has branched from the 11516th revision of SVN.
> > The URL of the branch is
> http://qeforge.qe-forge.org/svn/q-e/branches/espresso-3drismscf .
> >
> > > Did you develop 3D-RISM-SCF as external plug-in or directly inside the
> QE code?
> > The 3D-RISM-SCF was implemented directly inside the Q.E. code.
> > Source files in Modules/ and PW/ were mainly modified.
> >
> > > Do you have extensive tests to validate your implementation?
> > Yes, I prepare some tests or examples:
> > /branches/espresso-3drismscf/espresso/PW/examples/RISM_example .
> > And I confirm that these examples provide reasonable results.
> >
> > > Do you have one or more reference papers that explains the method
> utilized?
> > Yes, main reference papers are
> > H.Sato et al., J. Chem. Phys. 2000, 112, 9463 , and
> > A.Kovalenko, F.Hirata, Chem. Phys. Lett. 1998, 290, 237 .
> > Some formulas are utilized in the 3D-RISM-SCF, and
> > their references are written in comments of corresponding source codes
> or manuals.
> >
> > > Is your code suitable for general public release under GPL license?
> > Yes, my code is based on GPL license (
> http://www.gnu.org/copyleft/gpl.txt).
> > I have wrriten so, in header comments of the source codes.
> >
> > > Are you willingness to maintain and take care of bug fixes and
> improvements of this particular piece of code for at least one year
> starting from the release date?
> > Of course, I will maintain the code.
> >
> > Regards,
> > Satomichi Nishihara
>
> --
> Mr. Filippo SPIGA, M.Sc.
> Quantum ESPRESSO Foundation
> http://fspiga.github.io ~ skype: filippo.spiga
>
> «Nobody will drive us out of Cantor's paradise.» ~ David Hilbert
>
> *****
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-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
hone +39-0432-558216, fax +39-0432-558222
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