[Pw_forum] Problems Computing Cholesky for VC-Relax of MnO2

[Lorenzo Paulatto]

On 01/09/17 23:04, Lance Kavalsky wrote:
>     nspin=2,
>     lda_plus_u=.TRUE.
>     hubbard_U(1)= 3.9
>     starting_magnetization(1)=0.5
>    starting_magnetization(2)=-0.5
>
I would be that it is the GGA+U correction that is causing problems, not 
the position of the atoms. Does your calculation converge without the 
+U? Does it converge wit ha very small +U value?

I also think, your smearing is a bit large for the number of k-points 
you have, this should not be a problem for convergence, but can affect 
the accuracy of your results.

>     diagonalization = 'cg'
>
Don't use CG, it is slow and does not converge "better" than davidson.

Why does everyone use CG diagonalization first thing when they have the 
slightest problem? (It is a serious question, if it is in some tutorial 
somewhere that tutorial needs to be corrected!)


-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 442 79822 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/423 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05

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