[CPMD-list] Davidson diago of TDDFT

[Eung-Gun Kim]

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.

Best regards,

EG Kim

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 *********************** 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
 ****************************************************************
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***   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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