9. Structure selection for DFT calculations¶
9.2. search_poscar_variance¶
- Searching for a DFT structure for validating and improving a trial CE using the simulated annealing.
- DFT structures used for constructing the trial CE is specified by CORRELATION file.
- Available only for binary system.
Input files
Output files
- POSCAR_new
9.3. MKPOS.in¶
Searching for a structure with the lattice constructed by the 2x2x1 expansion of a 4-atoms unit cell (16-atoms cell). The structure has 12 A-atoms (spin=+1) and 4 B-atoms (spin=-1). The structure is optimized for clusters specified by CLUSTERINDEX.
ISUB = 1
NUCELL = 2 2 1
NCHANGE = 4
SPIN = 1 -1
NALLCLUSTER = 53
CLUSTERINDEX = 0 1 2 3 4 5 8 16 35 49 48
TEMPINIT = 1000
TEMPFINAL = 1
TEMPMUL = 0.99
NSTEP = 20
9.3.1. ISUB tag¶
Sublattice indexes for considering atomic configurations. Atomic configurations are considered on ISUBth lattice sites of UPOSCAR (line 6).
- Default : 1
- Example : ISUB = 1 3
9.3.2. NCHANGE tag¶
Number of atoms. In N-nary systems, set N-1 kinds of atoms. The number of the other kind of atoms is automatically set to (number of lattice sites - NCHANGE).
- Default : none
- Example : NCHANGE = 16
9.3.3. SPIN tag¶
Spin values of atoms. In binary systems, SPIN tag has two kinds of values. The same correspondence between spins and atom types used in correlation should be used here.
- Default : none
- Example : SPIN = 1 -1
In the above example, spin values of NCHANGE atoms are set to -1.
9.3.4. NUCELL tag¶
A structure is searched for using the NUCELL expansion of the unit cell.
- Default : none
- Example : NUCELL = 2 2 2
9.3.5. NALLCLUSTER tag¶
Number of all clusters included in CORRELATION file.
- Default : none
- Example : NALLCLUSTER = 53
9.3.6. CLUSTERINDEX tag¶
Indexes of clusters used for the trial CE.
- Default : none
- Example : CLUSTERINDEX = 0 1 2 3 4 5 8 16 35 48 49
9.3.7. TEMPINIT tag, TEMPFINAL tag¶
Initial and final temperatures in the simulated annealing.
- Default : none
- Example : TEMPINIT = 1
- Example : TEMPFINAL = 0.001
9.3.8. TEMPMUL tag¶
Exponential base for an automatic setting of temperatures in the simulated annealing. Set values ranged from 0 to 1.
- Default : none
- Example : TEMPMUL = 0.9
9.3.9. NSTEP tag¶
Number of steps for simulated annealing at one temperature.
- Default : none
- Example : NSTEP = 20
9.4. variance_energy¶
- Calculating the mean variance of the predicted energy.
Input files
- LS.in
- CORRELATION
- VARIANCE
- MEAN
Output files
- Mean variance of the predicted energy
9.5. variance_stpop¶
- Under development.
- Generating VARIANCE and MEAN files required in search_poscar_variance.
- VARIANCE and MEAN files can be generated by calculating correlation functions using correlation for random structures generated by mkposcar and calculating their means and variances.
Input files
Output files
- VARIANCE
- MEAN