[Pw_forum] Re: Pw_forum digest, Vol 1 #1208 - 1 msg

[Axel Kohlmeyer]

On Mon, 30 Oct 2006, Amit Kumar wrote:

AK>   >Why the manual is not as clear as ABINIT in PWSCF????
AK> 
AK>     because we made the choice to make the code better than the manual,
AK> rather the
AK> the other way around ;-)
AK> 
AK> 
AK>   Respected Users,
AK> 
AK>   >>>>>>>>>> It's definitely Good  Choice
AK>   but not the best !!!!! It would be better if the manual and the code -
AK> both are
AK>   equally  good.
AK>   Writing a good manual is not as difficult as  writing  a beutiful code.
AK>   I think any project asistant can do it.

well, are you willing to assign somebody to do it?
are you willing to help out with it?

AK>   I don't know why in Example directory there are so many simple example
AK> programs
AK>   (
AK>   Al , Ni, Cu, C,
AK>   Si, etc. etc.)???????? It would be better if there is some simple examples
AK> and at
AK>   least one example of
AK>   some complex material of some difficult structure (i.e. non cubic say
AK> monoclinic
AK>   structure).
AK>   You know there are so many tutorial on how to handle simple cubic system.
AK>   But no (as far as I know) tutorial on how to construct a supercell for a
AK> monoclin
AK>   ic structure?????

so start writing one, and ask people here to correct it.
_this_ is the way things work in 'community projects'.

AK>   I think my question is not a stupid one. Because I have checked almost all
AK> the
AK>   letters of the PWFORUM
AK>    and almost half of them are just trivial one (like What's the difference
AK> between
AK>    alat and bohr??? Is it posiible to include
AK>    spin in PWSCF????  How to calculate electron phonon coupling using
AK> PWSCF????? All
AK>    are very very trivial
AK>     questions.). What do you people think???????
AK>     If you think that PWFORUM is only for experts then you can creat another
AK> forum PW
AK>    FORUM_for_novice.

i think you are missing the point of a forum. splitting it does not help
you a tiny bit, since to give good answers, you have to have good 
questions. if people only ask trivial questions (and it depends a _lot_
on the personal perspective what is a trivial question!!) you will
only see trivial answers.

you have to realize, that nobody here has the time or gets paid to 
provide you with a custom tutorial for your personal needs. the 
'contract' usually is that you do a step towards people providing 
answers, i.e. make it easy to answer. right now i only see you
complaining a lot in a style this is not respecting the large 
amounts of work many, many people have put into the package to 
make it as good as it is now.


AK>   Because it's very difficult to find out useful informations in the sea of
AK> trivial questions.
AK>   I really want to learn how to handle the complicated structures in
AK> pwscf????

so what is wrong with starting to learn the code using simple
structures and then slowly move towards more complicated ones,
once you are confident with what you have learned?

[...]


AK>   I'll be  highly obliged if you kindly give me some useful references for
AK> supercell construction.

after all you remarks about trivial questions, what is so difficult
for you. unless you let us know where you are stumbling, nobody will
help you. the quality of information you can get, completely depends
on the quality of information you provide. as far as i recollect, you
have the space group already, you have the irreducible positions of your
atoms, now you just need to apply the symmetry operations included
(usually not a big problem, if you enter the positions in fractional
coordinates).

AK>   By the way, many many thanks for all who gave me a long reply and
AK> informations about references on the
AK>   web.

yes, but have you _looked_ at the stuff? ...or even tried it.

one of the most common mistakes that people do when trying to 
do calculations with package programs like quantum espresso, 
is that they start with too complicated problems, so they cannot
tell, what part of the input they don't understand. it takes
a little longer to do this in stages.

...and again, please don't forget to submit your tutorial once
you figured out what you needed in your case. ;-)


axel.


AK> 
AK>   With best regards,
AK>   Amit
AK> 

-- 
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
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If you make something idiot-proof, the universe creates a better idiot.