[CPMD-list] On PCG Minimize!

[Juerg Hutter]

Hi

the PCG minimizer is sometimes traped into a situation
where the step and the orthogonalization cancel,
leading to very small LAMBDA. If this happens only a restart
is possible.

Juerg

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Juerg Hutter                   Phone : ++41 1 635 4491
Physical Chemistry Institute   FAX   : ++41 1 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
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On Tue, 15 Jul 2003, [gb2312] Adrain Zhou wrote:

> Dear all,
>
> It seems there are some problems when using PCG Minimize to perform a multisteps wavefunction optimization. It is as follows,
>
>  LINE SEARCH : LAMBDA=.103           ENERGY =          -294.14310
>  228  3.006E-04   3.043E-06    -294.142940   -4.685E-06     43.33
>  LINE SEARCH : LAMBDA=.113E-01       ENERGY =          -294.14314
>  229  5.253E-04   4.688E-06    -294.142920    2.063E-05     40.45
>  LINE SEARCH : LAMBDA=.116E-02       ENERGY =          -294.14278
>  230  7.913E-04   9.229E-06    -294.142801    1.182E-04     40.08
>  LINE SEARCH : LAMBDA=.217E-03       ENERGY =          -294.14273
>  231  8.708E-04   1.001E-05    -294.142741    6.047E-05     39.11
>  LINE SEARCH : LAMBDA=.407E-04       ENERGY =          -294.14272
>  232  8.895E-04   1.086E-05    -294.142725    1.576E-05     40.98
>  LINE SEARCH : LAMBDA=.764E-05       ENERGY =          -294.14272
>  233  8.932E-04   1.086E-05    -294.142722    3.149E-06     42.24
>  LINE SEARCH : LAMBDA=.143E-05       ENERGY =          -294.14272
>  234  8.939E-04   1.086E-05    -294.142721    5.747E-07     39.37
> ~
> LAMBDA is less than 0.01,  the convergence never meet! When I just stop at the 120th step, and then restart again. The convergence reached very fast! It only take another 20 steps.  It is so strange!
>
> Can anyone tell me what's wrong with it?
>
> Many thanks in advance!
>
> Zhou
>
>
>
>
>
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