[Pw_forum] problems with converge of geometric optimization
Stefano de Gironcoli
degironc at sissa.it
Thu Sep 16 10:50:43 CEST 2010
except for the first 2 atoms and a few more in the cell the forces are
below threshold...
The energy criterion is probably already satisfied (it usually converge
faster than the forces).
Are the atoms with comparatively large forces close to each others and
alway the same or are they
a random set that change from one iteration to the other ? Do they form
a cluster where something
special is expected to happen ? You could try to take the last
configuration and restart the relaxation
from scratch freezing all the atoms whose forces are below threshold so
as to reduce the dimension of
the subspace that bfgs is dealing with...
However the fact that damped dynamics finds problems to converge may
mean that there is something
unstable in your calculation.. are you sure that the cutoffs (wfc and
rho) are sufficient, the BZ sampling is
appropriate for the smearing width you are using...
stefano
Stephan Rix wrote:
> @Stefano
> I have listed the forces from the last bfgs iteration. The forces are in the
> same range for the other iterations.
> The etot_conv_thr is set to 1.0D-4, the forc_conv_thr to 1.0D-3.
>
> @Jia
> I've tried setting ion_dynamics to damp. However, then I run into difficulty
> with the electronic convergence.
>
> Thanks again.
>
> Forces from last bfgs iteration:
> atom 1 type 2 force = 0.00674604 0.00401572 -0.00315882
> atom 2 type 2 force = -0.00707328 -0.00401102 -0.00417376
> atom 3 type 1 force = 0.00015167 -0.00003914 0.00011509
> atom 4 type 2 force = -0.00016229 -0.00052862 0.00042288
> atom 5 type 2 force = 0.00015237 -0.00005063 -0.00033087
> atom 6 type 2 force = 0.00097198 0.00025690 0.00085239
> atom 7 type 2 force = -0.00020876 0.00063517 0.00036422
> atom 8 type 2 force = 0.00057032 0.00054804 0.00024175
> atom 9 type 2 force = 0.00096382 -0.00038407 0.00067724
> atom 10 type 2 force = -0.00027981 -0.00030741 -0.00017944
> atom 11 type 2 force = 0.00014642 0.00002012 -0.00002955
> atom 12 type 1 force = -0.00022861 0.00033720 0.00044263
> atom 13 type 1 force = 0.00034998 -0.00016970 0.00062187
> atom 14 type 1 force = -0.00008588 -0.00012786 0.00006090
> atom 15 type 1 force = 0.00189702 0.00094614 -0.00025442
> atom 16 type 2 force = 0.00050876 0.00005659 0.00049815
> atom 17 type 2 force = 0.00088281 -0.00040997 0.00090335
> atom 18 type 2 force = 0.00134491 0.00032421 -0.00078394
> atom 19 type 2 force = 0.00066250 0.00025287 -0.00049312
> atom 20 type 2 force = -0.00011040 -0.00050559 -0.00006915
> atom 21 type 2 force = 0.00095934 -0.00035701 -0.00081817
> atom 22 type 2 force = -0.00038611 -0.00007281 -0.00001118
> atom 23 type 2 force = 0.00115667 0.00046339 -0.00028953
> atom 24 type 1 force = 0.00114906 -0.00047371 0.00049679
> atom 25 type 1 force = -0.00090091 0.00041464 0.00047287
> atom 26 type 1 force = -0.00127753 -0.00043198 -0.00016529
> atom 27 type 1 force = 0.00092469 -0.00029180 0.00027208
> atom 28 type 2 force = -0.00004433 -0.00023892 0.00041675
> atom 29 type 2 force = 0.00100550 -0.00031420 0.00113785
> atom 30 type 2 force = 0.00000884 -0.00111712 0.00068738
> atom 31 type 2 force = 0.00003832 -0.00009958 0.00076318
> atom 32 type 2 force = 0.00056036 0.00058104 0.00185944
> atom 33 type 2 force = 0.00069824 0.00004986 0.00197662
> atom 34 type 2 force = 0.00007865 -0.00031354 -0.00024944
> atom 35 type 2 force = 0.00040935 -0.00065039 0.00079960
> atom 36 type 1 force = 0.00054453 -0.00050520 -0.00081090
> atom 37 type 1 force = -0.00014881 0.00019052 -0.00056561
> atom 38 type 1 force = -0.00069173 0.00086720 0.00049374
> atom 39 type 1 force = -0.00032728 -0.00048677 0.00049346
> atom 40 type 2 force = 0.00005298 -0.00003038 0.00057008
> atom 41 type 2 force = 0.00052392 0.00031805 0.00092472
> atom 42 type 2 force = 0.00053091 0.00148619 0.00034716
> atom 43 type 2 force = -0.00139237 -0.00074654 -0.00130242
> atom 44 type 2 force = -0.00015835 0.00027715 -0.00041422
> atom 45 type 2 force = 0.00098086 -0.00018579 -0.00095187
> atom 46 type 2 force = -0.00064724 -0.00000916 0.00016756
> atom 47 type 2 force = 0.00368611 -0.00002795 0.00045003
> atom 48 type 1 force = 0.00031498 -0.00033410 -0.00002164
> atom 49 type 1 force = -0.00072047 0.00063453 0.00013858
> atom 50 type 1 force = 0.00054850 0.00029128 0.00078326
> atom 51 type 1 force = -0.00018902 0.00061944 0.00105489
> atom 52 type 2 force = -0.00043475 0.00002882 0.00006407
> atom 53 type 2 force = -0.00056709 0.00012075 0.00041822
> atom 54 type 2 force = -0.00056741 0.00024715 0.00023894
> atom 55 type 2 force = -0.00041280 0.00059675 0.00160623
> atom 56 type 2 force = 0.00014651 0.00028960 0.00159954
> atom 57 type 2 force = -0.00171450 0.00002096 0.00247953
> atom 58 type 2 force = -0.00017183 0.00085781 0.00007596
> atom 59 type 2 force = -0.00102680 0.00054910 -0.00040500
> atom 60 type 1 force = -0.00009379 0.00014378 -0.00127470
> atom 61 type 1 force = 0.00012531 -0.00025665 -0.00112033
> atom 62 type 1 force = 0.00080427 -0.00056558 0.00101772
> atom 63 type 1 force = -0.00498284 0.00033298 -0.00350540
> atom 64 type 2 force = -0.00086830 0.00066374 0.00055719
> atom 65 type 2 force = -0.00073070 -0.00057656 0.00125530
> atom 66 type 2 force = -0.00083096 -0.00034313 -0.00035115
> atom 67 type 2 force = 0.00106363 -0.00040306 -0.00077587
> atom 68 type 2 force = 0.00071954 0.00035647 -0.00132880
> atom 69 type 2 force = 0.00017170 0.00042807 -0.00121455
> atom 70 type 2 force = -0.00025769 -0.00395602 0.00174604
> atom 71 type 2 force = -0.00129773 -0.00071931 0.00039821
> atom 72 type 1 force = -0.00301732 -0.00065251 0.00435206
> atom 73 type 1 force = 0.00329464 0.00030046 0.00470849
> atom 74 type 1 force = 0.00484552 -0.00038429 -0.00313326
> atom 75 type 1 force = 0.00022645 -0.00012545 0.00117296
> atom 76 type 2 force = -0.00037719 0.00045763 -0.00319435
> atom 77 type 2 force = -0.00040814 0.00008839 0.00005440
> atom 78 type 2 force = 0.00033602 -0.00001990 0.00046392
> atom 79 type 2 force = 0.00028389 -0.00067385 0.00205674
> atom 80 type 2 force = -0.00004079 0.00009821 -0.00339820
> atom 81 type 2 force = -0.00030699 -0.00038710 0.00080237
> atom 82 type 2 force = 0.00008637 -0.00026351 -0.00008527
> atom 83 type 2 force = -0.00156333 0.00023433 0.00055603
> atom 84 type 1 force = -0.00025828 -0.00004507 0.00074608
> atom 85 type 1 force = 0.00057079 -0.00060726 -0.00014710
> atom 86 type 1 force = -0.00011808 -0.00005027 0.00081874
> atom 87 type 1 force = -0.00282270 0.00131933 -0.00472331
> atom 88 type 2 force = -0.00158720 0.00067537 0.00032135
> atom 89 type 2 force = -0.00039389 -0.00111775 0.00005539
> atom 90 type 2 force = -0.00056433 -0.00005048 -0.00167901
> atom 91 type 2 force = -0.00014824 0.00003539 -0.00627238
> atom 92 type 2 force = -0.00205334 0.00037334 -0.00044205
> atom 93 type 2 force = -0.00025693 0.00472185 0.00131091
> atom 94 type 2 force = -0.00366386 0.00012575 0.00058219
> atom 95 type 1 force = -0.00339605 -0.00077984 0.00213525
> atom 96 type 1 force = 0.00430043 0.00036977 0.00195456
> atom 97 type 1 force = 0.00347151 -0.00182346 -0.00493084
> Total force = 0.025508 Total SCF correction = 0.000128
>
> Stephan Rix
> Institute for Inorganic und Analytical Chemistry
> Johannes Gutenberg-University Mainz, Germany
>
>
> Date: Wed, 15 Sep 2010 17:10:07 +0200
> From: Stefano de Gironcoli <degironc at sissa.it>
> Subject: Re: [Pw_forum] problems with converge of geometric
> optimization
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <4C90E1CF.6040400 at sissa.it>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> This happens when the energy landscape become noisy compared with the
> expected energy decrease in the relaxation steps.
> This can happen when you are very close to the minimum.
> How large are your forces ? How tight is your force/energy threshold ?
> stefano
>
> Stephan Rix wrote:
>
>> I am trying to calculate an H-center in CaF2, and I am having trouble with
>> the geometry optimization.
>> I have tried adjusting various parameters such as ion dynamics, trust
>> radius, convergence tresholds, but it seems that convergence cannot be
>> improved.
>>
>> Using bfgs I always get the following error:
>>
>> %%%%%%%%%%%%%%%%%%%%%%%%%%
>> from bfgs : error # 1
>> bfgs history already reset at previous step
>> %%%%%%%%%%%%%%%%%%%%%%%%%%
>>
>> Alternatively the electonic convergence gets extremely slow.
>>
>> In addition, no matter what parameters I adjust the total forces in the
>> system never converge, e.g.
>> Total force = 0.026394 Total SCF correction = 0.000314
>> Total force = 0.018379 Total SCF correction = 0.000282
>> Total force = 0.018824 Total SCF correction = 0.000120
>> Total force = 0.018857 Total SCF correction = 0.000155
>> Total force = 0.020215 Total SCF correction = 0.000193
>> Total force = 0.058765 Total SCF correction = 0.000241
>> Total force = 0.016998 Total SCF correction = 0.000205
>> Total force = 0.042967 Total SCF correction = 0.000238
>> Total force = 0.106226 Total SCF correction = 0.000073
>> Total force = 0.137142 Total SCF correction = 0.000071
>> Total force = 0.109549 Total SCF correction = 0.000108
>> Total force = 0.068723 Total SCF correction = 0.000103
>> Total force = 0.076599 Total SCF correction = 0.000168
>> Total force = 0.033233 Total SCF correction = 0.000342
>> Total force = 0.026883 Total SCF correction = 0.000248
>> Total force = 0.025846 Total SCF correction = 0.000378
>> Total force = 0.025596 Total SCF correction = 0.000225
>> Total force = 0.025482 Total SCF correction = 0.000275
>> Total force = 0.025508 Total SCF correction = 0.000128
>>
>> I am thankful for any suggestions.
>>
>> Stephan Rix
>> Institute for Inorganic und Analytical Chemistry
>> Johannes Gutenberg-University Mainz, Germany
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://www.democritos.it/mailman/listinfo/pw_forum
>>
>>
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
More information about the users
mailing list