[Pw_forum] Fwd: different symmetry when using equivalent representation

[Paolo Giannozzi]

On Dec 17, 2009, at 18:08 , Jess Kondor wrote:

> The reason I indeed asked this question is why code
> cannot find all symmetries if lattice vectors are given
> with nine (9) significant digits

for lattice vectors (not atomic positions) actually there is a
different check. This is performed in either PW/hexsym.f90
or PW/cubicsym.f90 (depending on the kind of symmetry)
and is much stricter (maybe too much). See lines:
            if ( abs(DBLE(nint(value))-value) > 1.0d-8) then
               !
               ! if a noninteger is obtained, this implies that this  
operation
               ! is not a symmetry operation for the given lattice
               !
               go to 10
            end if
P.
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Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222