> We still need to work on this. For simple molecules, TNCG indeed
> works better
> than L_BFGS. But for other molecules, TNCG is taking longer than
> L-BFGS, which
> is odd. I'll put together some test cases and post them -- maybe there are
> things we can tweak in the input paramters.
This is the expected behavior. TNCG will always use significantly less
minimization steps than LBFGS, but a single step can be a lot more
expensive. It all depends on the Hessian structure of the molecule at
hand. In terms of total wall-clock time, LBFGS often beats TNCG.
However, if you need very low gradient RMS, say < 1e-04, TNCG will
readily beat LBFGS and oftentimes LBFGS would give up before reaching
convergence.
Istvan
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Received on Fri Dec 11 2009 - 07:30:03 PST
