swsym.position#

Syntax#

[r, aIdx, opInfo] = swsym.position(sym,r0)

[r, aIdx, opInfo] = swsym.position(sym,r0,fid)

[r, aIdx, opInfo] = swsym.position(sym,r0,fid,tol)

Description#

[r, aIdx, opInfo] = swsym.position(sym, r0, fid, tol) generates all symmetry equivalent atomic positions from a given space group and coordinates of the symmetry inequivalent atoms. If fid is defined, the result are printed onto the corresponding file.

Input Arguments#

sym

Either the label of the space group or the index from the International Tables of Crystallography or string containing the space group operators in the same format as used in the symmetry.dat file (for details see swsym.str).

r0

Atomic position in lattice units in a matrix with dimensions of \([3\times n_{atom}]\).

fid

If non-zero, the symmetry operators will be printed to the file identified by fid, the following values are valid:

  • 0 no printed output (default),

  • 1 standard output (Command Line),

  • fid text file opened before using fid = fopen(path).

tol

Tolerance, distance within two atoms are considered identical, default value is \(10^{-5}\) lattice unit. Necessary to check for badly defined atomic positions (when atoms are not exactly on the symmetry element) and to avoid numerical errors.

Output Arguments#

r

All generated atomic positions stored in a matrix with dimensions of \([3\times n_{genAtom}]\).

aIdx

The index of the symmetry inequivalent position for every generated position, stored in a row vector with \(n_{genAtom}\) number of elements.

opInfo

Structure with the following fields:

  • ismoved Cell, where each element contains a vector with logical values, whether the given operator moved the atom or not. Each vector has a dimensions of \([1\times n_{sym}]\), where the \(n_{sym}\) is multiplicity of the general position.

  • opmove The rotation operator that moved the original atom the equivalent position stored in a matrix with dimensions of \([3\times 3\times n_{genAtom}]\).

See Also#

swsym.operator