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# LNMR SYM RED

LNMR_SYM_RED = .TRUE. | .FALSE.

Default: **LNMR_SYM_RED** = .FALSE.

Description: discard symmetry operations that are not consistent with the way *k*-space derivative are calculated in the linear response calculations of chemical shifts.

The star on which the *k*-space derivative is calculated is oriented along the cartesian directions in *k*-space. If the symmetry operations in *k*-space do not map this star onto itself, erroneous results can be obtained. To have VASP check for such operations, set LNMR_SYM_RED=.TRUE., and such operations will be discarded, resulting in a larger IBZ. In case of any doubt set LNMR_SYM_RED=.TRUE. Beware: It matters how the real space lattice vectors are set up relative to the cartesian coordinates in POSCAR. It determines the orientation of the *k*-space star and hence can affect the efficiency via the number of *k*-points in the IBZ.

## Related Tags and Sections

LCHIMAG, DQ, ICHIBARE, NLSPLINE