The optimization of 3 lattice parameters in wien2k is quite some work
and requires large computational effort.
To use just 10 structures is the minimal requirement to determine 10
fit-parameters. Usually, such a solution will suffer from the smallest
numerical noise and not give accurate results.
In any case, your procedure gave you its solution as output (but as
mentioned above, it might suffer from noise and is probably very
inaccurate):
At the bottom you found:
> Parabolic equation of state: info 8
>
> E = x1 + x2(a-x3)^2
>
> + x4(b-x5)^2 + x6(a-x3)(b-x5)
>
> + x7(c-x8)^2 + x9(a-x3)(c-x8) + x10(b-x5)(c-x8)
>
> Fitparameter are
>
> -195722.961991 0.024128 15.665728 0.031781
>
> 15.308083 0.060289 0.069122 11.327643
>
> -5.455925 -5.218681
So this gives your a,b,c as 15.666, 15.308, 11.328
On the other hand it seems that you got the lowest total energies when
a is small and b is large !!! So I doubt that this is an accurate
solution. You need more points (3x3x3 or, of course, even more ...)
On 10/14/2014 09:35 AM, Shafqat Hussain Shah wrote:
Dear All
I have trouble in extracting the optimized lattice parameters (a,b c)
from my optimized structures using option 6 plus MSR1a.
My system of interest has an orthorhombic structure. I want to
simultaneously optimize its volume and internal atomic positions. I have
used option 6 (with number of structures 10 at 1% change) of the
optimizer plus MSR1a with default parameters in case.inM. All the 10
structures are geometry optimized well and forces on atoms are less than
the tolerances. Then I used the command
parabolfit_lapw -t 3 -f BIFOfm -scf *abc*.scf
to fit the data as shown in the end.
My question ; what is the best way to extract the optimized lattice
parameters for my system from this procedure????
I have tried following things but to no avail.
1> I tried to plot the data (a,b,c, E) with a scatter plot in Origin
where E was color coded. The number of data points was not sufficient
(10) and it did not give the exact values of the optimized lattice
parameters.
2> I tried to find the minima of the fitted function with first order
and second order derivatives (Hessian) but it did not give any information.
3> I looked up in the mailing list but could not find the answer to
my problem.
Any suggestion to extract the optimized lattice parameters from the data
will be highly appreciated.
Many thanks in advance.
Dr. Shafqat Hussain Shah
PS: I am using parallel WIEN2k_13 on a multicore machine.
shs28@apollo1:~/WIEN2k/BIFO/BIFOfm> parabolfit_lapw -t 3 -f BIFOfm -scf
*abc*.scf
BIFOfm.ene and BIFOfm.latparam generated
Enter dimension of fit (number of variable lattice parameters, 1-6):
3 fitcase 10 parameter
lowest data point: -195723.042487450 15.0632000000000
15.7881200000000 11.2255400000000
10 -195723.042487450 -195722.955530700
-195722.964214750 -195722.971284580 -195722.954407870
-195722.971888480 -195722.957634800 -195722.968628590
-195722.944729150 -195723.042426910
I INITIAL X(I) D(I)
1 -0.195723D+06 0.100D+01
2 0.100000D+00 0.600D+00
3 0.150632D+02 0.600D+00
4 0.100000D+00 0.600D+00
5 0.157881D+02 0.600D+00
6 0.000000D+00 0.600D+00
7 0.100000D+00 0.600D+00
8 0.112255D+02 0.600D+00
9 0.000000D+00 0.600D+00
10 0.000000D+00 0.600D+00
IT NF F RELDF PRELDF RELDX MODEL STPPAR D*STEP NPRELDF
0 1 0.237D-01
1 3 0.217D-01 0.85D-01 0.83D+00 0.7D-06 G 0.7D-02 0.4D+00 0.10D+01
2 4 0.621D-02 0.71D+00 0.84D+00 0.3D-06 G 0.4D-02 0.2D+00 0.10D+01
3 6 0.333D-02 0.46D+00 0.47D+00 0.7D-07 G 0.1D+00 0.4D-01 0.82D+00
4 8 0.310D-02 0.69D-01 0.14D+00 0.2D-06 G 0.4D-01 0.1D+00 0.67D+00
5 9 0.257D-02 0.17D+00 0.19D+00 0.2D-06 G 0.3D-01 0.9D-01 0.55D+00
6 10 0.234D-02 0.87D-01 0.96D-01 0.2D-06 G 0.2D-01 0.8D-01 0.41D+00
7 11 0.229D-02 0.22D-01 0.19D-01 0.2D-07 G 0.1D-01 0.1D-01 0.35D+00
8 13 0.226D-02 0.16D-01 0.16D-01 0.6D-07 S 0.3D-01 0.3D-01 0.14D+00
9 14 0.225D-02 0.15D-02 0.12D-02 0.8D-08 G 0.9D-01 0.5D-02 0.10D+01
10 16 0.223D-02 0.12D-01 0.12D-01 0.5D-07 G 0.3D-01 0.3D-01 0.23D+00
11 17 0.220D-02 0.93D-02 0.60D-02 0.4D-07 G 0.1D-01 0.2D-01 0.10D+01
12 18 0.219D-02 0.64D-02 0.41D-02 0.2D-07 G 0.1D-01 0.2D-01 0.10D+01
13 20 0.217D-02 0.11D-01 0.12D-01 0.5D-07 G 0.3D-01 0.3D-01 0.28D+00
14 21 0.215D-02 0.77D-02 0.65D-02 0.2D-07 G 0.3D-01 0.1D-01 0.10D+01
15 22 0.212D-02 0.13D-01 0.19D-01 0.8D-07 S 0.2D-01 0.5D-01 0.35D+00
16 23 0.206D-02 0.28D-01 0.31D-01 0.7D-07 S 0.2D-01 0.4D-01 0.00D+00
17 25 0.202D-02 0.23D-01 0.24D-01 0.7D-07 S 0.6D-02 0.5D-01 0.00D+00
18 26 0.197D-02 0.23D-01 0.26D-01 0.4D-07 G 0.5D-02 0.7D-01 0.10D+01
19 27 0.192D-02 0.23D-01 0.55D-01 0.1D-06 G 0.6D-02 0.1D+00 0.10D+01
20 28 0.181D-02 0.56D-01 0.97D-01 0.9D-07 G 0.6D-02 0.1D+00 0.10D+01
21 29 0.168D-02 0.76D-01 0.12D+00 0.9D-07 G 0.6D-02 0.1D+00 0.10D+01
22 30 0.152D-02 0.95D-01 0.16D+00 0.1D-06 G 0.6D-02 0.1D+00 0.10D+01
23 31 0.130D-02 0.14D+00 0.18D+00 0.1D-06 G 0.6D-02 0.1D+00 0.10D+01
24 32 0.111D-02 0.15D+00 0.16D+00 0.1D-06 G 0.6D-02 0.1D+00 0.10D+01
25 33 0.943D-03 0.15D+00 0.15D+00 0.2D-06 G 0.5D-02 0.1D+00 0.10D+01
26 35 0.804D-03 0.15D+00 0.14D+00 0.2D-06 G 0.2D-02 0.1D+00 0.10D+01
27 37 0.747D-03 0.71D-01 0.72D-01 0.7D-07 G 0.2D-01 0.5D-01 0.10D+01
28 39 0.699D-03 0.63D-01 0.64D-01 0.8D-07 G 0.4D-02 0.5D-01 0.10D+01
29 40 0.622D-03 0.11D+00 0.24D+00 0.4D-06 G 0.4D-02 0.2D+00 0.10D+01
30 41 0.430D-03 0.31D+00 0.37D+00 0.5D-06 G 0.3D-02 0.2D+00 0.10D+01
31 42 0.364D-03 0.15D+00 0.45D+00 0.5D-06 S 0.6D-02 0.2D+00 0.62D+00
32 43 0.195D-03 0.46D+00 0.50D+00 0.5D-06 G 0.2D-02 0.2D+00 0.10D+01
33 44 0.117D-03 0.40D+00 0.43D+00 0.5D-06 G 0.2D-02 0.2D+00 0.10D+01
34 45 0.662D-04 0.44D+00 0.51D+00 0.5D-06 G 0.1D-02 0.2D+00 0.10D+01
35 47 0.325D-04 0.51D+00 0.69D+00 0.5D-06 S-G 0.6D-03 0.2D+00 0.10D+01
36 49 0.120D-04 0.63D+00 0.93D+00 0.5D-06 S-G 0.2D-03 0.2D+00 0.10D+01
37 53 0.328D-05 0.73D+00 0.15D+01 0.1D-08 S 0.1D+02 0.1D-02 0.00D+00
38 54 0.238D-05 0.27D+00 0.27D+00 0.2D-08 G 0.6D-01 0.1D-02 0.10D+01
39 58 0.404D-06 0.83D+00 0.97D+00 0.2D-06 G 0.1D-04 0.1D+00 0.10D+01
40 59 0.337D-07 0.92D+00 0.91D+00 0.2D-07 G 0.1D-06 0.6D-02 0.10D+01
41 60 0.318D-07 0.57D-01 0.42D-01 0.5D-08 G 0.6D-07 0.2D-02 0.10D+01
42 61 0.315D-07 0.71D-02 0.53D-02 0.2D-08 G 0.1D-06 0.7D-03 0.10D+01
43 62 0.315D-07 0.87D-03 0.66D-03 0.6D-09 G 0.3D-07 0.2D-03 0.10D+01
44 63 0.315D-07 0.13D-03 0.13D-03 0.3D-09 G 0.0D+00 0.1D-03 0.13D-03
45 67 0.315D-07 0.68D-07 0.13D-06 0.2D-12 G 0.2D+00 0.8D-07 0.10D+01
46 72 0.315D-07-0.44D-07 0.74D-08 0.8D-14 G 0.2D+02 0.3D-08 0.23D-04
***** FALSE CONVERGENCE *****
FUNCTION 0.315053D-07 RELDX 0.794D-14
FUNC. EVALS 72 GRAD. EVALS 460
PRELDF 0.737D-08 NPRELDF 0.227D-04
I FINAL X(I) D(I) G(I)
1 -0.195723D+06 0.100D+01 -0.141D-08
2 0.241284D-01 0.568D+00 0.430D-07
3 0.156657D+02 0.671D+00 -0.947D-08
4 0.317814D-01 0.903D+00 -0.114D-08
5 0.153081D+02 0.646D+00 0.442D-08
6 0.602895D-01 0.508D+00 -0.512D-09
7 0.691222D-01 0.457D+00 -0.595D-10
8 0.113276D+02 0.161D+01 -0.143D-07
9 -0.545592D+01 0.110D+00 -0.489D-09
10 -0.521868D+01 0.535D+00 0.446D-09
Parabolic equation of state: info 8
E = x1 + x2(a-x3)^2
+ x4(b-x5)^2 + x6(a-x3)(b-x5)
+ x7(c-x8)^2 + x9(a-x3)(c-x8) + x10(b-x5)(c-x8)
Fitparameter are
-195722.961991 0.024128 15.665728 0.031781
15.308083 0.060289 0.069122 11.327643
-5.455925 -5.218681
lattic parameters energy de(EOS)
15.063200 15.788120 11.225540 -195723.042487 -0.000001
14.912570 15.947590 11.338930 -195722.955531 -0.000094
15.063200 15.947590 11.338930 -195722.964215 0.000194
15.213830 15.947590 11.338930 -195722.971285 -0.000037
15.063200 15.788120 11.338930 -195722.954408 -0.000100
15.063200 16.107070 11.338930 -195722.971888 -0.000028
15.063200 15.947590 11.225540 -195722.957635 0.000000
15.063200 15.947590 11.452320 -195722.968629 0.000000
14.912570 15.788120 11.338930 -195722.944729 0.000065
14.912570 15.947590 11.225540 -195723.042427 0.000001
Sigma: 0.000084
Optionally create data points from fit function
Enter number of datapoints for your 3 dimensional Energy surface
NI=0 terminates; NI=1 will use 1 specific value in I-th component and
allows to
generate 2D-cuts
0.000u 0.004s 0:00.01 0.0% 0+0k 1952+8io 5pf+0w
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--
P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at
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