Firefly and PC GAMESS-related discussion club

 
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Thomas
thomaspijper@hotmail.com

GDIIS (geometry optimization using direct inversion in the iterative sub-space) is
an extrapolation method analogous to the DIIS method used for the wavefunction 
optimization. The implementation used in Firefly is unique and uses ideas presented in 
references 5 and 6. GDIIS is usually superior to RFO and QA, especially on flat regions 
on the PES. For this reason, it is the default optimizer.

5. S. Vogel, T. H. Fischer, J. Hutter, H. P. Luthi Int. J. Quantum Chem. 45, 6, 679-688 (1993)
6. H. Sellers Int. J. Quantum Chem. 45, 1, pages 31-41 (1993)

>>Thank you for your honest reply. I also do not know technically how GDIIS works that makes it superior than other methods. Why it is faster and reliable - that I do not know despite that I'm using it. Nevertheless, thanks for the insights!
>
>
>The original description of the algorithm is :

>Pál Császár, Péter Pulay, Geometry optimization by direct inversion in the iterative subspace, Journal of Molecular Structure, Volume 114, 1984, Pages 31-34, ISSN 0022-2860, http://dx.doi.org/10.1016/S0022-2860(84)87198-7http://dx.doi.org/10.1016/S0022-2860(84)87198-7http://dx.doi.org/10.1016/S0022-2860(84)87198-7http://dx.doi.org/10.1016/S0022-2860(84)87198-7http://dx.doi.org/10.1016/S0022-2860(84)87198-7http://dx.doi.org/10.1016/S0022-2860(84)87198-7http://dx.doi.org/10.1016/S0022-2860(84)87198-7http://dx.doi.org/10.1016/S0022-2860(84)87198-7.
>(http://www.sciencedirect.com/science/article/pii/S0022286084871987http://www.sciencedirect.com/science/article/pii/S0022286084871987http://www.sciencedirect.com/science/article/pii/S0022286084871987http://www.sciencedirect.com/science/article/pii/S0022286084871987http://www.sciencedirect.com/science/article/pii/S0022286084871987http://www.sciencedirect.com/science/article/pii/S0022286084871987http://www.sciencedirect.com/science/article/pii/S0022286084871987http://www.sciencedirect.com/science/article/pii/S0022286084871987)

>I do not have access to the article, but you may be able to get it from your institution..

>Pedro