[Pw_forum] correction to functional.f90 (4.1): optx identified as a meta-GGA functional

[Paolo Giannozzi]

Latévi Max LAWSON DAKU wrote:

> the OPTX functional was flagged as a meta-GGA.

thank you for reporting this

> By the way, the following comment is written in functional.90.
> 
>   !              "olyp"  = "nox+lyp+optx+blyp"!!! UNTESTED !!!
> 
> Does this mean, simply, that the olyp shortname is not well tested?

exactly. It should work, because it has been working in some version
in the past, but if you have the possibility to verify it, please do
it, report if that comment can be removed

> By the way, I noticed that the keyword "blyp" is used for designating
> both the blyp XC functional and the lyp gradient correction to
> correlation. 

the logic used to label XC functionals, based on four keywords,
seemed a smart method years ago, but it has been outsmarted by
the ever-increasing number of XC functionals, and by a choice
for the meaning of "blyp" that turned out not to be a good one.
Changing the way XC functionals are labelled (in particular,
fixing the "blyp" inconsistency you mention) might break old
pseudopotentials (the XC functional is read from pseudopotential
files).

> Finally, I've inserted the following lines in the subroutine dft_name(),
> Line 609:
> 
>   else if (iexch_==0.and.icorr_==3.and.igcx_==6.and.igcc_==3) then
>      shortname_ = 'OLYP'

that's a good solution...your changes will go in the next version

Paolo
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy