[Pw_forum] converge problem in calculating the vacancy on TiO2 surfaces

[Axel Kohlmeyer]

On Sun, 1 Mar 2009, vega lew wrote:

VL> Dear sir,
VL> 
VL> I apologize for my pool understanding of your mails concerning my problems
VL> of convergence for SCF.
VL> 
VL> Because I am not strong enough with the theory background, I am not
VL> sensitive with what you said before. Now, you tell me how to overcome the
VL> problems so detail. I think I really benefit from your mail this time.

ok. here we go. writing something like that paragraph below
is like waving a red in front of a bull (and people that know
me in person know that i can do a pretty good impersonation of
that when i'm angry). sensitive minds, please hit delete right now.

VL> By the way, my understanding on quantum mechanism or quantum chemistry is
VL> not good enough. My purpose is to use the code to solve the problem and make
VL> better understanding with the materials we focus on. Do you think the theory
VL> background is really important for all the users of scientific code, even
VL> for researchers in chemical engineering or applied physics?

please read this paragraph again, hit yourself on the head 
three times with a hard item and then answer it yourself.

YES!!!!!!!!!

if you go to your local do-it-yourself store, you'll see tons of
powertools for every purpose. have you seen what these powertools
can do in the hand of somebody without sufficient understanding
of how they work?? do you know how many accidents (severed fingers,
punctured hands, etc.) happen because of that, every year?
there _is_ no "just using" of tools. without sufficient knowledge
you can get lucky and get it right, but how often?

mind you, you don't have to become that much of an expert so you
could write your own software or develop new algorithms, but you 
also have to keep the "garbage-in garbage-out" principle in mind. 
you have to have at least the ability to tell whether your results 
are gold or cow dung, and for that - sorry there ain't no escape
from the blues - you will have to learn the fundamentals. or to
give another example: what good would a pocket calculator be to you,
if you don't know the difference between adding and multiplying?

...and for that matter, asking questions on a mailing list is 
no replacement for working (not reading) through textbooks and
building your experience. the mailing list should be used _after_
there is no more help to be found in the textbook, not before.

looks like i managed to stay reasonably calm this way.

enjoy your "cigar",
   axel.

VL> 
VL> thank you for your time.
VL> 
VL> vega
VL> 

-- 
=======================================================================
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
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.