[Wien] survey results

Laurence Marks L-marks at northwestern.edu
Fri Jun 28 18:24:02 CEST 2013


Thanks, it looked unusual. Removing "|| 13" fixes it, i.e. (for others)

# Li, Si
sub rkm4_5 {
    my ($a) = @_ ;
    if ( $a == 3 || $a == 14 )  {
        return 1;
    } else {
        return 0;
    }
}



On Fri, Jun 28, 2013 at 11:13 AM, Peter Blaha
<pblaha at theochem.tuwien.ac.at> wrote:
> The answer is simple: it is a  bug.
>
> As listed on the faq page  http://www.wien2k.at/reg_user/faq/rkmax.html
> the necessary RKmax for Al and O are both 6.5.
> Therefore the spheres should be "equal".
>
> These RKmax estimates come from total energy tests of an atom in a
> simple box.
>
> For Al, however, the convergence depends a lot on the semicore-treatment
> and at first I had obtained a RKmax=4.5 for Al, but later on it was
> updated to 6.5.
> Unfortunately, setrmt has the Al in both, the 4.5 and 6.5 section and
> thus uses "4.5", which will then make the Al sphere smaller than O.
>
> # Li, Al, Si
> sub rkm4_5 {
>      my ($a) = @_ ;
>      if ( $a == 3 || $a == 13 || $a == 14 )  {
>         return 1;
>
> Removing a == 13 from the above, should fix the problem.
>
> I'll update the sources.
>
> On 06/28/2013 05:24 PM, Laurence Marks wrote:
>> As a follow up, can I request a little more information comparing the
>> New and Old setrmt algorithms perhaps in a FAQ. I just noticed a very
>> large difference between them for bulk LaAlO3, e.g.
>>
>> Old:
>> atom  Z   RMT-max   RMT
>>   1   8.0  1.77   1.77
>>   2  13.0  1.77   1.77
>>   3  57.0  2.50000  2.50000
>>
>> New
>> atom  Z   RMT-max   RMT
>>   1   8.0  1.95   1.95
>>   2  13.0  1.60   1.60
>>   3  57.0  2.50000  2.50000
>>
>> I assume that the New algorithm is better and this is "right", but  it
>> would be helpful to know why O is now being chosen so much larger than
>> Al, more like the relative atomic radii
>>
>>
>> On Thu, Jun 27, 2013 at 1:47 PM, Peter Blaha
>> <pblaha at theochem.tuwien.ac.at> wrote:
>>> I've updated    http://www.wien2k.at/reg_user/faq/rkmax.html
>>>
>>> Maybe it helps if I put a link in w2web in the initialization section next to the
>>> RKmax input/editing ?  (But which experienced user is using w2web for intialization ?)
>>>
>>>
>>> Am 27.06.2013 16:49, schrieb Stefaan Cottenier:
>>>>
>>>> One week ago, a two-question survey was posted on this mailing list.
>>>> Here comes the result and a discussion/interpretation of the data.
>>>>
>>>> The goal of the survey was to collect quantitative information on the
>>>> following hypothesis:
>>>>
>>>> "In the transition from code development to code usage, inevitable some awareness and knowledge about fine (?) details gets lost. Developers tend to think that users know
>>>> more than they actually do. While users tend to think that there are less hidden subtleties than there actually are. It might well be that grey intermediate area of
>>>> supposed/lacking knowledge is far larger than either of both parties thinks it is."
>>>>
>>>> The discussion of one week ago about the relation between RKmax and Rmt offered an opportunity to collect some data to examine this hypothesis. The topic was one about
>>>> which an experienced user could think: "You can't use wien2k properly if you don't know this." While a 'general user' could think: "I can survive without this."
>>>>
>>>> 34 people filled out the survey. Less than the 100 I hoped for, but nevertheless sufficient for meaningful conclusions. The results can be found for a while at
>>>> https://dl.dropboxusercontent.com/u/10829484/Results%20RKmax%20survey.pdf (attachment too large for this list).
>>>>
>>>> 1/3 of the respondents say they could have given the right answer on the RKmax question themselves. 2/3 say this was new for them. As one can expect that users who have no
>>>> clue at all about the topic are less
>>>> likely to take part in the survey, it seems fair to conclude that 75% or more of the wien2k community was not aware about this RKmax issue. A
>>>> number that might surprise some people.
>>>>
>>>> Whereas the first question of the survey roughly probes 'understanding', the second question of the survey asked about 'experience' (measured as the amount of years someone
>>>> has been using wien2k). Slightly less than one half of the respondents were relatively new users (<3y), the other half were quite to very much experienced (>3y, >7y). It is
>>>> interesting to correlate the answers on both questions in a knowledge-vs-experience graph (3th page of
>>>> https://dl.dropboxusercontent.com/u/10829484/Results%20RKmax%20survey.pdf ) :
>>>>
>>>> It is reassuring to observe in this correlation that roughly spoken understanding seems to increase as a function of experience (or time). Nevertheless, even in the
>>>> category of the most experienced users (>7y), there are still almost twice as many who were not aware of the RKmax issue than those who were (26% vs. 15%).
>>>>
>>>> This is only a rough observation, that does not pretend to be a statistically significant scientific study. It does point to a trend, however.
>>>>
>>>> The bottom line: is there anything all of us, as a community, can do to improve the knowledge transfer towards 'general users'? Feel free to discuss this on this mailing
>>>> list, and in particular, to post suggestions.
>>>>
>>>> Stefaan
>>>>
>>>>
>>>>
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>>>
>>> --
>>> -----------------------------------------
>>> Peter Blaha
>>> Inst. Materials Chemistry, TU Vienna
>>> Getreidemarkt 9, A-1060 Vienna, Austria
>>> Tel: +43-1-5880115671
>>> Fax: +43-1-5880115698
>>> email: pblaha at theochem.tuwien.ac.at
>>> -----------------------------------------
>>> _______________________________________________
>>> Wien mailing list
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>>> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>>
>>
>
> --
>
>                                        P.Blaha
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
> Email: blaha at theochem.tuwien.ac.at    WWW:
> http://info.tuwien.ac.at/theochem/
> --------------------------------------------------------------------------
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-- 
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what
nobody else has thought"
Albert Szent-Gyorgi


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