Just re-ran the sqm test with Dave's tight sqm settings. For both
LBFGS and TNCG I used the same LBFGS memory depth=3.
XMIN method Final energy Nof outer minim
steps Time
(xmin_iter)
PRCG (conjgrad) -120.50380837969715 9352
38m26.130s
LBFGS -120.50380707124714 3087
4m47.540s
TNCG -120.50380888493964 225
2m27.690s
Both LBFGS and TNCG give slightly lower energies in a little fewer
steps with more memory depth, but the difference is insignificant.
Istvan
Quoting istvan.kolossvary.hu:
> Andreas,
>
>> Here my question:
>> I wanted to play around with scfconv, tight_p_conv and grms_tol and
>> turned on verbosity. For the ash test I get for the standard non-verbose
>> output
>> ...
>> sqm energy: 50 -179.5406 0.001885
>> sqm energy: 60 -179.5406 0.000357
>> Final SCF energy is -179.540648949995
>>
>> Turning on verbosity shows that there is *many more* calls to the
>> energy/gradient routines than what is apparent from sqm's output. I
>> printed the number of force calls in the do while loop in xmin.f and it
>> counts 870 calls... this means that the TNCG optimizer does not need 60+
>> steps but rather almost 900... if this is correct there is still
>> something wrong with the optimizer, interface, or gradients. So what
>> does the variable xmin_iter actually count? Or did I overlook something?
>> Switching back to LBFGS results in 846 force calls.
>
> When you run TNCG, it uses gradient evaluations for computing
> Hessian-vector matrix products in the inner conjugate gradient loop.
> This is where the numerous calls come from. For some systems the
> total number of function calls, which is ultimately the rate
> limiting calculation, turns out to be less with LBFGS than with TNCG
> even though the latter uses a lot less outer minimization steps
> (counted by xmin_iter). For most systems, however, especially when
> you set the minimization convergence criterion really tight, TNCG
> wins out.
>
> Istvan
>
>
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Received on Sat Dec 19 2009 - 09:00:02 PST
