On Wed, Dec 09, 2009, Andreas Goetz wrote:
>
> This still leaves the question why sqm requires so many steps to
> converge. For my NMA test for example I got 51/87/188 steps with
> orca/mopac2009/sqm (all optimizations in Cartesian coordinate space with
> tight convergence criteria, see below).
Thanks for the info. Istvan and I spent all day today looking at
minimizations and lmod in both sander and sqm. I'll be checking some things
in soon. I think we have fixed the problems in sander (zero rms gradient,
bad results for the lmod tests) and fixed up other printouts.
There are still some things to look at in terms of taking too many steps
in sqm. It may be a problem with slightly inaccurate gradients, even though
one can take sqm minimizations down to very small values. Some molecules seem
to work *much* better than others, and we are still trying things. But right
now, this seems to be a matter of efficiency, not accuracy of the final
result.
I'm glad to have the orca and mopac2009 results for comparison. Have you
ever compared the SCF energies for a given structure in sqm vs orca vs
mopac2009? (We did comparisons to Gaussian and Martin Field's programs in the
original paper.)
...thanks....dac
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Received on Wed Dec 09 2009 - 19:30:02 PST
