[Wien] Extraction of optimized lattice parameters using Simultaneous Optimization with option 6

Tue Oct 14 13:31:38 CEST 2014

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 at 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: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
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