Documentation for NEWTON_CG and Newton_MINRES

Questions
#1

Is there any example documentation for NEWTON_CG and Newton_MINRES? There is none I could find in the manual. NEWTON_CG and Newton_MINRES are mentioned in passing but no information appears to be present for their application. There appears to be no information on DIIS control with NEWTON_CG and Newton_MINRES as well. And no information on any parameters associated with NEWTON_CG and Newton_MINRES is apparent in the manual.

Your help is appreciated.

#2

These are relative new options and there is not documentation at the present time. I will post a ticket.

#3

Thanks John. Is their an example file I can get? I really need to try these options out on a system I am characterizing.

#4

Hi Jim,
After some discussion on the developer forum it appears these options were added ca. 2015 but never proved to be very useful due to slow convergence away from the minimum, and were never tested in a comprehensive way. I’ve asked for a sample job and will post one here if someone comes up with something. I agree there should be a sample if it’s going to be in the manual but it’s not clear at this point whether this is a feature that was ready to be advertised.

#5

Thanks John. I appreciate your looking into this.

#6

Courtesy of Yuezhi Mao, here is an example where DIIS is used to converge to 1e-4 a.u. then NEWTON-CG leads to fast convergence afterwards.

$molecule
0 2
8            .000000     .000000     .108786
1            .000000     .000000    -.870284
$end

$rem
jobtype sp
method  wB97X-D
basis 6-31g
gen_scfman true
unrestricted true
thresh 14
symmetry false
sym_ignore true
gen_scfman_hybrid_algo true
gen_scfman_algo_1 diis
gen_scfman_iter_1 50
gen_scfman_conv_1 4
gen_scfman_algo_2 newton_cg
gen_scfman_iter_2 10
gen_scfman_conv_2 8
internal_stability true
$end
#7

John,

Thanks! I’ll give it a try.

Jim