[Pw_forum] Fw: SCF convergence in magnetic system during vc-relax

MKondrin mkondrin at hppi.troitsk.ru
Sun Feb 22 15:53:34 CET 2015


talpha beta wrote:
> I'm having lots of trouble getting SCF convergence during a vc-relax 
> calculation. The first ~30 geometry relaxation steps will converge, 
> and then at some point, it doesn't reach convergence, and restarting 
> from there doesn't obtain convergence with a variety of input 
> parameters. I allow up to 400 steps for convergence; the calculation 
> gets close to energy convergence in the first ~40 steps and then 
> oscillates like this:
>
>
>
>      total energy              =   -3730.97262054 Ry
>      total energy              =   -3730.97260717 Ry
>      total energy              =   -3730.97261229 Ry
>      total energy              =   -3730.97261830 Ry
>      total energy              =   -3730.97258457 Ry
>      total energy              =   -3730.97261372 Ry
>      total energy              =   -3730.97268144 Ry
>      total energy              =   -3730.97262740 Ry
>      total energy              =   -3730.97259749 Ry
>      total energy              =   -3730.97264306 Ry
>      total energy              =   -3730.97263999 Ry
>      total energy              =   -3730.97266124 Ry
>      total energy              =   -3730.97263072 Ry
>      total energy              =   -3730.97261754 Ry
>      total energy              =   -3730.97260856 Ry
>      total energy              =   -3730.97261221 Ry
>      total energy              =   -3730.97282659 Ry
>      total energy              =   -3730.97252377 Ry
>      total energy              =   -3730.97259997 Ry
>      total energy              =   -3730.97261600 Ry
>      total energy              =   -3730.97264186 Ry
>      total energy              =   -3730.97263070 Ry
>      total energy              =   -3730.97260955 Ry
>      total energy              =   -3730.97267593 Ry
>      total energy              =   -3730.97263180 Ry
>      total energy              =   -3730.97259580 Ry
>      total energy              =   -3730.97269934 Ry
>      total energy              =   -3730.97275706 Ry
>      total energy              =   -3730.97245909 Ry
>      total energy              =   -3730.97258422 Ry
>      total energy              =   -3730.97257852 Ry
>      total energy              =   -3730.97255901 Ry
>      total energy              =   -3730.97259179 Ry
>      total energy              =   -3730.97262199 Ry
>      total energy              =   -3730.97259627 Ry
>      total energy              =   -3730.97261363 Ry
>      total energy              =   -3730.97262780 Ry
>      total energy              =   -3730.97273314 Ry
>      total energy              =   -3730.97251796 Ry
>      total energy              =   -3730.97259430 Ry
>      total energy              =   -3730.97258802 Ry
>      total energy              =   -3730.97257319 Ry
>      total energy              =   -3730.97257817 Ry
>      total energy              =   -3730.97254693 Ry
>      total energy              =   -3730.97253977 Ry
>      total energy              =   -3730.97254394 Ry
>      total energy              =   -3730.97254471 Ry
>      total energy              =   -3730.97282186 Ry
>      total energy              =   -3730.97250548 Ry
>      total energy              =   -3730.97248482 Ry
>      total energy              =   -3730.97247040 Ry
>      total energy              =   -3730.97239243 Ry
>      total energy              =   -3730.97226787 Ry
>      total energy              =   -3730.97222104 Ry
>      total energy              =   -3730.97219271 Ry
>      total energy              =   -3730.97222772 Ry
>      total energy              =   -3730.97244430 Ry
>      total energy              =   -3730.97291917 Ry
>      total energy              =   -3730.97279625 Ry
>      total energy              =   -3730.97207455 Ry
>      total energy              =   -3730.97249466 Ry
>      total energy              =   -3730.97247870 Ry
>      total energy              =   -3730.97252112 Ry
>      total energy              =   -3730.97253986 Ry
>      total energy              =   -3730.97254804 Ry
>      total energy              =   -3730.97264250 Ry
>      total energy              =   -3730.97257019 Ry
>      total energy              =   -3730.97258495 Ry
>      total energy              =   -3730.97282802 Ry
>      total energy              =   -3730.97259481 Ry
>      total energy              =   -3730.97254903 Ry
>      total energy              =   -3730.97252576 Ry
>      total energy              =   -3730.97249424 Ry
>      total energy              =   -3730.97237618 Ry
>      total energy              =   -3730.97263210 Ry
>      total energy              =   -3730.97248594 Ry
>      total energy              =   -3730.97240941 Ry
>      total energy              =   -3730.97283533 Ry
>      total energy              =   -3730.97270373 Ry
>      total energy              =   -3730.97250770 Ry
>      total energy              =   -3730.97252933 Ry
>      total energy              =   -3730.97254547 Ry
>      total energy              =   -3730.97250286 Ry
>      total energy              =   -3730.97247847 Ry
>      total energy              =   -3730.97244537 Ry
>      total energy              =   -3730.97244642 Ry
>      total energy              =   -3730.97241718 Ry
>      total energy              =   -3730.97242648 Ry
>      total energy              =   -3730.97296957 Ry
>      total energy              =   -3730.97258207 Ry
>      total energy              =   -3730.97250996 Ry
>      total energy              =   -3730.97271424 Ry
>      total energy              =   -3730.97258977 Ry
>      total energy              =   -3730.97259733 Ry
>      total energy              =   -3730.97264651 Ry
>      total energy              =   -3730.97263695 Ry
>      total energy              =   -3730.97259491 Ry
>      total energy              =   -3730.97261988 Ry
>      total energy              =   -3730.97272206 Ry
>      total energy              =   -3730.97261538 Ry
>      total energy              =   -3730.97256870 Ry
>      total energy              =   -3730.97252499 Ry
>      total energy              =   -3730.97252092 Ry
>      total energy              =   -3730.97252172 Ry
>      total energy              =   -3730.97257641 Ry
>      total energy              =   -3730.97256721 Ry
>      total energy              =   -3730.97257116 Ry
>      total energy              =   -3730.97256679 Ry
>      total energy              =   -3730.97274213 Ry
>      total energy              =   -3730.97253146 Ry
>      total energy              =   -3730.97249600 Ry
>      total energy              =   -3730.97250428 Ry
>      total energy              =   -3730.97254304 Ry
>      total energy              =   -3730.97256978 Ry
>      total energy              =   -3730.97273656 Ry
>      total energy              =   -3730.97248342 Ry
>      total energy              =   -3730.97240302 Ry
>      total energy              =   -3730.97243408 Ry
>      total energy              =   -3730.97241248 Ry
>      total energy              =   -3730.97238562 Ry
>      total energy              =   -3730.97251359 Ry
>      total energy              =   -3730.97247234 Ry
>      total energy              =   -3730.97264369 Ry
>      total energy              =   -3730.97259674 Ry
>      total energy              =   -3730.97266736 Ry
>      total energy              =   -3730.97257325 Ry
>      total energy              =   -3730.97247542 Ry
>      total energy              =   -3730.97252150 Ry
>      total energy              =   -3730.97248097 Ry
>      total energy              =   -3730.97246945 Ry
>      total energy              =   -3730.97253380 Ry
>      total energy              =   -3730.97255385 Ry
>      total energy              =   -3730.97254624 Ry
>      total energy              =   -3730.97277355 Ry
>      total energy              =   -3730.97261952 Ry
>      total energy              =   -3730.97255316 Ry
>      total energy              =   -3730.97253355 Ry
>      total energy              =   -3730.97247700 Ry
>      total energy              =   -3730.97253033 Ry
>      total energy              =   -3730.97247318 Ry
>      total energy              =   -3730.97244662 Ry
>      total energy              =   -3730.97246907 Ry
>      total energy              =   -3730.97244103 Ry
>      total energy              =   -3730.97306304 Ry
>      total energy              =   -3730.97245649 Ry
>      total energy              =   -3730.97247788 Ry
>      total energy              =   -3730.97281807 Ry
>      total energy              =   -3730.97269524 Ry
>      total energy              =   -3730.97274703 Ry
>      total energy              =   -3730.97267068 Ry
>      total energy              =   -3730.97251186 Ry
>      total energy              =   -3730.97245086 Ry
>      total energy              =   -3730.97258230 Ry
>
> I input a starting_magentization value close to the converged values 
> from previous runs
> I increase the number of bands (nbnd) to well above #electrons/2
> diagonalization = 'cg' or 'david'
> electron_maxstep = 400
> mixing_mode = 'plain' or 'local-TF'
> mixing_beta = as low as 0.05
>
> what are the other tricks/tips to obtain convergence?  
>
>
> ------------------------------------------------------------------------
>
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Wouldn't you just increase etot_conv_thr (in &control namelist) to some 
larger value? The total energy is high  enough so the oscillation at the 
level of 1e-8 of the absolute value may be due to the calculation errors.

M. V. Kondrin



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