[Wien] :FCHECK in Wien2k 13.1 vs. 14

Elias Assmann elias.assmann at gmail.com
Mon Nov 30 16:00:03 CET 2015


Hi List,

I reply to this thread
<http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg13276.html>.
This is still about the same set of oxide calculations.

Laurence Marks alerted me that :FCHECK (sum of forces) was large (see
below).  This is the same over a set of similar calculations (somewhat
different structures, GGA+U vs. plain GGA), and does not seem to get
better even after hundreds of calculations.

I have been using the latest Wien2k (14.2), but I did similar things
before with 13.1 and I did not remember having this problem, at least
to this extent.  So I compiled 13.1 (same options as 14.2) and
switched one of my calculations to it for 10 iterations.

Indeed, it seems that 13.1 is more “well-behaved” in this case than
14.2 — in any case they are different.  Below, I include some output
of the two versions, starting from the same charge density in both
cases.

As you can see, the two versions are the more or less the same in the
first iteration, but diverge from there; and 13.1 seems to converge,
in contrast to 14.2.  Also, 13.1 seems to be already satisfied with
the structure (it switches MSR1a off), while 14.2 continues
minimizing.  The greed (on whose smallness Prof. Marks also commented)
is pretty similar.

To me, that suggests that I should go on with these calculations using
the older Wien.  Is there any reason that doing so might be “unsafe”?


	Elias


14.2 :FCHECK:     11.008001043    12.164812176   -14.416571844
     :FCHECK:    249.814119002   264.664202568  -694.164686632
     :FCHECK:     97.292437031   103.207655853  -256.561081883
     :FCHECK:    126.184534662   136.666423509   -39.224005265
     :FCHECK:    176.349427337   188.815368048    36.914398561
     :FCHECK:     50.400659984    67.046955772    76.978472788
     :FCHECK:    -74.640170442    25.157628216   121.498217602
     :FCHECK:    -82.337983720    28.388321933   121.952351989
     :FCHECK:   -130.382154150    24.859863620   204.399962720
     :FCHECK:    -39.381668995   -31.379111345    91.507308943

13.1 :FCHECK:     11.009473749    12.153718710   -14.482142314
     :FCHECK:     10.707248409    11.500977675   -16.514184574
     :FCHECK:     10.289877753    10.742969135   -10.026151044
     :FCHECK:      7.566779454     6.128096382    -3.725471547
     :FCHECK:      3.572302068     1.087140350     6.011501945
     :FCHECK:     -4.275691705    -7.052038873    31.588782325
     :FCHECK:     -6.385420320    -8.403344519    33.874614737
     :FCHECK:     -6.106651082    -8.096761064    35.566398852
     :FCHECK:     -5.627436387    -7.565248768    32.843232377
     :FCHECK:     -3.074299958    -4.674255384    27.987425362

14.2 :ENE  : *WARNING** TOTAL ENERGY      -222784.46215529
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46926026
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46462435
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46263442
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46223935
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46214440
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46218336
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46213858
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46236760
     :ENE  : *WARNING** TOTAL ENERGY      -222784.46181283

13.1 :ENE  : ********** TOTAL ENERGY      -222784.46212826
     :ENE  : ********** TOTAL ENERGY      -222784.46212374
     :ENE  : ********** TOTAL ENERGY      -222784.46212843
     :ENE  : ********** TOTAL ENERGY      -222784.46207306
     :ENE  : ********** TOTAL ENERGY      -222784.46209495
     :ENE  : ********** TOTAL ENERGY      -222784.46204241
     :ENE  : ********** TOTAL ENERGY      -222784.46199458
     :ENE  : ********** TOTAL ENERGY      -222784.46200681
     :ENE  : ********** TOTAL ENERGY      -222784.46200118
     :ENE  : ********** TOTAL ENERGY      -222784.46201120

(It appears that the warnings come from the forces.  As mentioned
before there is not :WAR tag.)

14.2 :DIS  :  ( 0.0048283 for atom    7 spin 1)      0.0015628
     :DIS  :  ( 0.1175699 for atom    5 spin 1)      0.0137938
     :DIS  :  ( 0.0692919 for atom    5 spin 1)      0.0083222
     :DIS  :  ( 0.0098508 for atom    7 spin 1)      0.0017036
     :DIS  :  ( 0.0167530 for atom    5 spin 1)      0.0022822
     :DIS  :  ( 0.0278296 for atom    7 spin 1)      0.0038446
     :DIS  :  ( 0.0366785 for atom    5 spin 1)      0.0048138
     :DIS  :  ( 0.0371346 for atom    5 spin 1)      0.0047958
     :DIS  :  ( 0.0559135 for atom    5 spin 1)      0.0068198
     :DIS  :  ( 0.0157960 for atom    5 spin 1)      0.0035943

13.1 :DIS  :  ( 0.0048362 for atom    7 spin 1)      0.0015593
     :DIS  :  ( 0.0022134 for atom   12 spin 2)      0.0012247
     :DIS  :  ( 0.0052633 for atom    5 spin 1)      0.0014252
     :DIS  :  ( 0.0015732 for atom    5 spin 1)      0.0007705
     :DIS  :  ( 0.0046946 for atom    7 spin 1)      0.0010640
     :DIS  :  ( 0.0018880 for atom    8 spin 2)      0.0011590
     :DIS  :  ( 0.0017283 for atom    5 spin 1)      0.0008169
     :DIS  :  ( 0.0009736 for atom    8 spin 2)      0.0006944
     :DIS  :  ( 0.0018888 for atom    5 spin 1)      0.0007013
     :DIS  :  ( 0.0009991 for atom    7 spin 1)      0.0003925

14.2 :MIX  :   PRATT  REG: 1.00E-06  GREED: 0.200
     :MIX  :   PRATT  REG: 1.00E-06  GREED: 0.200  Reduce 0.25  0.20
     :MIX  :   MSE1a  REG: 1.88E-06  GREED: 0.120  Newton 1.00  0.01
     :MIX  :   MSE1a  REG: 2.17E-06  GREED: 0.083  Newton 1.00  0.01
     :MIX  :   MSE1a  REG: 3.19E-06  GREED: 0.050  Newton 1.00  0.01
     :MIX  :   MSE1a  REG: 4.08E-06  GREED: 0.034  Newton 1.00  0.03
     :MIX  :   MSE1a  REG: 5.17E-06  GREED: 0.022  Newton 1.00  0.00
     :MIX  :   MSE1a  REG: 5.20E-06  GREED: 0.021  Newton 1.00  0.06
     :MIX  :   MSE1a  REG: 7.51E-06  GREED: 0.018  Newton 1.00  0.14
     :MIX  :   MSE1a  REG: 4.52E-06  GREED: 0.017  Newton 1.00  0.10

13.1 :MIX  :   PRATT  REG: 1.00E-06  GREED: 0.025
     :MIX  :   MSR1a  REG: 1.00E-06  GREED: 0.030  Newton 1.00  0.03
     :MIX  :   MSE1a  REG: 1.59E-06  GREED: 0.030  Newton 1.00  0.18
     :MIX  :   MSE1a  REG: 2.61E-06  GREED: 0.042  Newton 1.00  0.29
     :MIX  :   MSE1a  REG: 3.72E-06  GREED: 0.057  Newton 1.00  0.54
     :MIX  :   MSE1a  REG: 3.58E-06  GREED: 0.093  Newton 1.00  0.46
     :MIX  :   PRATT  REG: 1.00E-06  GREED: 0.025
     :MIX  :   MSR1   REG: 1.00E-06  GREED: 0.050  Newton 1.00  0.05
     :MIX  :   MSE1   REG: 1.60E-06  GREED: 0.050  Newton 1.00  0.22
     :MIX  :   MSE1   REG: 2.41E-06  GREED: 0.055  Newton 1.00  0.40

On 11/03/2015 02:47 PM, Laurence Marks wrote:
> I am not sure exactly what the problem(s) were, but from you case.scf it
> was "right" that there were Warnings
> 
> a) :FCHECK (bottom of case.scf) was large. This is the sum of all the
> forces, and should be small. Particularly for cells without inversion
> one can get bad, highly asymmetric densities in which case MSR1a can
> have problems.
> 
> b) The greed is small. Too small a value can be as bad as too large. I
> have struggled with this for years and failed to find a strong ansatz
> for this, although I believe the next release of the mixer will be better.



-- 
Elias Assmann
Institute of Theoretical and Computational Physics
TU Graz                   ⟨https://itp.tugraz.at/⟩


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