[Pw_forum] Davidson diagonalization with overlap

[Giuseppe Mattioli]

Dear Cao
Why do you think that this is a problem? "Davidson" is the standard diagonalization algorithm of 
electronic degrees of freedom...
I suggest accurate reading of the QE manual...
HTH
Giuseppe

On Tuesday 15 November 2011 09:14:45 Cao TF wrote:
> Dear QE users
>          I am relaxing the structure of graphene with hydrogen adsorbed on
> it. But in iteration there is " Davidson diagonalization with overlap". 
> What can be the reasons?  And how to solve it . Any suggestions will be
> appreciated. Here is part of the  out file:
>  Writing output data file graphene.save
>      NEW-OLD atomic charge density approx. for the potential
>
>      total cpu time spent up to now is 127989.94 secs
>
>      per-process dynamical memory:   116.7 Mb
>
>      Self-consistent Calculation
>
>      iteration #  1     ecut=    30.00 Ry     beta=0.70
>      Davidson diagonalization with overlap
>      ethr =  1.00E-06,  avg # of iterations =  4.0
>
>      total cpu time spent up to now is 129567.23 secs
>
>      total energy              =   -1141.65432551 Ry
>      Harris-Foulkes estimate   =   -1141.65612583 Ry
>      estimated scf accuracy    <       0.00636573 Ry
>
>      iteration #  2     ecut=    30.00 Ry     beta=0.70
>      Davidson diagonalization with overlap
>      ethr =  1.58E-06,  avg # of iterations =  2.0
>
>      total cpu time spent up to now is 130246.48 secs
>
>      total energy              =   -1141.65417045 Ry
>      Harris-Foulkes estimate   =   -1141.65465073 Ry
>      estimated scf accuracy    <       0.00113580 Ry
>
>      iteration #  3     ecut=    30.00 Ry     beta=0.70
>      Davidson diagonalization with overlap
>      ethr =  2.83E-07,  avg # of iterations =  2.7
>
>      total cpu time spent up to now is 131108.66 secs
>
>      total energy              =   -1141.65435750 Ry
>      Harris-Foulkes estimate   =   -1141.65436350 Ry
>      estimated scf accuracy    <       0.00002145 Ry
>
>      iteration #  4     ecut=    30.00 Ry     beta=0.70
>      Davidson diagonalization with overlap
> ------
> ======================================================================
> T.F.Cao  DFT and phonon physics
> ======================================================================
> Add: Research Laboratory for Computational Materials Sciences,
> Instutue of Solid State Physics,the Chinese Academy of Sciences,
> P.O.Box 1129, Hefei 230031, P.R.China
> Tel: 86-551-5591464-326(office)
> Fax: 86-551-5591434



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   Giuseppe Mattioli                            
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