Dear Dr. Gale,
I hope this message finds you well. I am a member of a laboratory that has been using GULP for a long time for materials modeling. However, most of the time, parameter adjustments are performed empirically and manually, when not found in the literature.
I recently started exploring the adjustment algorithms available in GULP, such as BFGS and SIMPLEX. Despite following the examples provided in the documentation, I found it difficult to use them; when activating the “fit” flag, errors appear, which I will show below.
In addition, I had doubts about the functionality described in the documentation related to the genetic algorithm: does it only search for possible structures or does it also adjust the parameters of the potentials? When discussing these questions with other users, I realized that they are recurrent in the community.
Another point that I did not find clarification in the manual was the meaning of the number that follows the “fractional” command, as well as the practical differences between the “fractional” and “frac” commands.
I would like to thank you in advance for your attention and availability. Below I have attached the input file corresponding to the problem to facilitate analysis, as well as the error that appears.
Kind regards,
Willamis A Silva
INPUT:
fit relax conp optimise properties compare phono distance
cell
5.4200 38.5800 5.5270 90.0 90.0 90.0
fractional 6
Y core 0.71400 0.03590 0.25000
Y core 0.29500 0.10760 0.28600
Y core 0.71500 0.17980 0.24300
Y core 0.29400 0.25000 0.29400
O core 0.50000 0.00000 0.47800
O shel 0.50000 0.00000 0.47800
O core 0.48900 0.07230 0.01900
O shel 0.48900 0.07230 0.01900
O core 0.46800 0.14360 0.99600
O shel 0.46800 0.14360 0.99600
F core 0.44200 0.21320 0.01000
F shel 0.44200 0.21320 0.01000
O core 0.00000 0.00000 0.05700
O shel 0.00000 0.00000 0.05700
F core 0.03100 0.06310 0.40000
F shel 0.03100 0.06310 0.40000
F core 0.94000 0.12730 0.12100
F shel 0.94000 0.12730 0.12100
F core 0.10300 0.19130 0.36900
F shel 0.10300 0.19130 0.36900
F core 0.92000 0.25000 0.12200
F shel 0.92000 0.25000 0.12200
space
39
temperature 293 K
cell
10.60380 10.60380 10.60380 90.0000 90.0000 90.0000
fraccional 6
Y core -0.03200 0.00000 0.25000
Y core 0.25000 0.25000 0.25000
O core 0.39110 0.15160 0.38270
O shel 0.39110 0.15160 0.38270
space
206
temperature 293 K
cell
6.35370 6.85450 4.39530 90.0000 90.0000 90.0000
fraccional 6
Y core 0.36730 0.25000 0.05910
F core 0.52270 0.25000 0.59100
F shel 0.52270 0.25000 0.59100
F core 0.16520 0.06430 0.37550
F shel 0.16520 0.06430 0.37550
space
62
temperature 293 K
species
Y core 3.00
O core 0.86902
O shel -2.86902
F core 0.59
F shel -1.59
buck
Y core O shell 1345.1000 0.3491 0.00 0.00 10.0 1 1 0
Y core F shel 1515.68 0.3011 0.0 0.0 12.0 0 0 0
O shell O shell 22764.00 0.1490 27.88 0.00 10.0 0 0 0
O shel F shel 100.54 0.0029 22.10 0.0 12.0 0 0 0
F shel F shel 1127.7 0.2953 15.83 0.0 12.0 0 0 0
spring
O 74.92
F 20.77
OUTPUT:
-
GENERAL UTILITY LATTICE PROGRAM *
-
Julian Gale *
-
Curtin Institute for Computation *
-
School of Molecular and Life Sciences *
-
Curtin University, Western Australia *
- Version = 6.0.0 * Last modified = 9th June 2021 *
!!!
!! ERROR : Incorrect potential coefficient input
!! : Error is apparently on line 64
!!!
Program terminated by processor 0 in potword22
STOP GULP terminated with an error