[CPMD-list] Davidson diago of TDDFT

[Eung-Gun Kim]

Dear Prof. Hutter,

Thanks very much for your kind reply.  Having another look at my output file
after reading your message carefully, I thought it might make it easier to tune
the parameters if the gradient information is also printed in the output file.

Best regards,

EG Kim

Quoting Juerg Hutter <hutter at pci.unizh.ch>:

> Hi
>
> > Dear List Subscriber,
> >
> > I am trying to calculate electronic spectra using TDDFT (v3.9.1).  When
> some of
> > the roots are not converged after the Davidson diago step of the TDDFT
> matrix, I
> > understand RDIIS kicks in.  What puzzles me in my calculation is the point
> where
> > this transition takes place.  It seems to me that RDIIS is switched on even
> > though either MAX ITER or MAX SUBSPACE of DAVIDSON DIAGO has not been
> exceeded
> > (see portions of my output below).  Is there a third criterion to stop
> DAVIDSON?
> >  Thanks very much for reading.
>
> If progress in the Davidson diagonalisation is very slow and the gradient
> is small enough, the program switches to RDIIS. This can be controled by
>
>   DAVIDSON RDIIS
>    nrdiismax,nrestdmax,rdiistin
>
> where nrdiismax is max number of rdiis steps
> nrestdmax maximum number of restarts
> rdiistin minimum gradient to start RDIIS
>
> regards
>
> Juerg Hutter
>
>
>
>
> >
> > Best regards,
> >
> > EG Kim
> >
> >
> #############################################################################
> >
> >  *********************** LINEAR RESPONSE ************************
> >  Step size for numeric dmu/dn :                          .500E-02
> >  Number of calculations for dmu/dn :                            2
> >  Maximum number of optimisation steps:                       1000
> >  Threshold for Hessian (Preconditioner)                     .5000
> >  Optimizer for LR equations                             AUTOMATIC
> >                     Size of ODIIS buffer                        5
> >                     Size of ZDIIS buffer                        4
> >                     Switch from PCG to ODIIS at         .1000E+00
> >                     Switch to full preconditioning at   .1000E-02
> >  Step length                                                .1000
> >  Convergence criteria                                   .1000E-04
> >  ****************************************************************
> >
> >  ***************************  TDDFT  ****************************
> >  Step size for numeric dmu/dn :                          .500E-02
> >  Number of calculations for dmu/dn :                            2
> >  Tamm-Dancoff Approximation
> >  Diagonalization Method                                  DAVIDSON
> >           Max. number of iterations                           200
> >           Convergence criteria                           .100E-06
> >           Max. size of Davidson matrix                         50
> >           RDIIS Parameters
> >           NTDIISMAX=  20      NRESTDMAX=   3  RDIISTIN=  .100E-02
> >  Number of Singlet States                                       3
> >  Forces calculated for state                                    1
> >  ****************************************************************
> > .
> > .
> > .
> > .
> > .
> > ***   SPECTRA| THE NEW SIZE OF THE PROGRAM IS 286956 KBytes ***
> >  ==                      SINGLET STATES                        ==
> >  NUMBER OF STATES TO BE INITIALIZED                             3
> >  TOTAL NUMBER OF TEST VECTORS                                   6
> >  ***   SPECTRA| THE NEW SIZE OF THE PROGRAM IS 319776 KBytes ***
> >  ================================================================
> >  ==            DAVIDSON DIAGONALISATION OF TDDFT MATRIX        ==
> >  ================================================================
> >   ITER      STATES      SUBSPACE             RESIDUAL        TCPU
> >      1           0             3        .13533773E-01       87.40
> >      2           0             6        .46776986E-02       88.93
> >      3           0             9        .30463019E-02       90.23
> >      4           0            12        .33203299E-02       91.35
> >      5           0            15        .22075106E-02       93.19
> >      6           0            18        .11336981E-02       96.40
> >      7           0            21        .67511167E-03       98.32
> >      8           0            24        .64601509E-03      100.01
> >      9           0            27        .57523001E-03      105.70
> >     10           0            30        .47208419E-03      373.56
> >     11           0            33        .36949736E-03      253.12
> >     12           0            36        .40133983E-03      752.00
> >     13           0            39        .59391461E-03     2563.71
> >  >>> RESIDUAL DIIS OPTIMIZATION OF ROOT                         1
> >   ITER      ENERGY      SUBSPACE             RESIDUAL        TCPU
> >      1     2.88328             1        .30627204E-04      108.58
> >      2     2.88311             2        .82109007E-05      155.98
> >      3     2.88299             3        .66425066E-05       61.41
> >      4     2.88291             4        .43031780E-05       53.93
> > .
> > .
> > .
> > .
> > .
> >
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> >
>