Hi, did this issue ever get resolved/answered? I would also be very interested in a solution/explanation of the behavior.
I also get relaxations where individual forces are higher than the threshold, without the line stating that "SCF correction compared to forces is large", in case that would be a reason here. Also happens in regular "relax" calculations. Thanks so much, Florian -- Florian Brown-Altvater PhD Candidate Neaton group UC Berkeley/LBNL Am 08.04.2015 um 12:07 schrieb Tianli Feng: > Dear All, > > I would really appreciate if anyone can help to explain a output in > relaxing a structure. I used vc-relax to relax a lattice > with forc_conv_thr set as 1.0D-9. After 44 steps, the results converge > as following: > > Forces acting on atoms (Ry/au): > > atom 1 type 1 force = 0.00000638 0.00000000 > 0.00000092 > atom 2 type 1 force = 0.00000602 0.00000000 > 0.00000671 > atom 3 type 1 force = -0.00000074 0.00000000 > 0.00000243 > atom 4 type 1 force = 0.00000358 0.00000000 > -0.00000082 > atom 5 type 2 force = -0.00000821 0.00000000 > -0.00000732 > atom 6 type 2 force = -0.00000635 0.00000000 > -0.00000202 > atom 7 type 2 force = 0.00000337 0.00000000 > -0.00000058 > atom 8 type 2 force = -0.00000406 0.00000000 > 0.00000068 > > Total force = 0.000018 Total SCF correction = 0.000002 > SCF correction compared to forces is large: reduce conv_thr to > get better values > > bfgs converged in 44 scf cycles and 43 bfgs steps > (criteria: energy < 1.0E-04, force < 1.0E-09, cell < 5.0E-01) > > The last line says the relaxation converges with force <1.0E-9, but I > saw the forces acting on each atom are not smaller than 1e-9. Does > anyone has experience on relaxing a lattice and know what is > happening? Many thanks!! > > Sincerely, > Best wishes, > Tianli > ------------ > Tianli Feng > Mechanical Engineering, Purdue University > ---The truth is not what you see, but what it is. > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum
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