[Q-e-developers] ibrav = 5, in INPUT_PW.def

[Paolo Giannozzi]

I see, you are right. I fixed it. Thank you

Paolo


On Wed, May 3, 2017 at 12:27 PM,  <nisihara225 at gmail.com> wrote:
> Dear Paolo,
>
>
>
> trigonal lattice (ibrav = 5) has same angles alpha = beta = gamma.
>
> However, only cos(gamma) or cosab is copied to celldm(4), as the source file
> (cell_base.f90, line211-240):
>
>
>
>      IF ( celldm(1) == 0.D0 .and. a /= 0.D0 ) THEN
>
>         !
>
>         celldm(1) = a / bohr_radius_angs
>
>         celldm(2) = b / a
>
>         celldm(3) = c / a
>
>         IF ( (ABS(cosab) > 1.0_dp) .OR. (ABS(cosac) > 1.0_dp) .OR. &
>
>              (ABS(cosbc) > 1.0_dp) ) CALL errore ('cell_base_init',&
>
>                          'incorrect values for cosab, cosac, cosbc',1)
>
>         !
>
>         IF ( ibrav == 14 ) THEN
>
>            !
>
>            ! ... triclinic lattice
>
>            !
>
>            celldm(4) = cosbc
>
>            celldm(5) = cosac
>
>            celldm(6) = cosab
>
>            !
>
>         ELSE IF ( ibrav ==-12 ) THEN
>
>            !
>
>            ! ... monoclinic P lattice, unique axis b
>
>            !
>
>            celldm(5) = cosac
>
>            !
>
>         ELSE
>
>            !
>
>            ! ... trigonal and monoclinic lattices, unique axis c
>
>            !
>
>            celldm(4) = cosab
>
>            !
>
>         ENDIF
>
>
>
> Then, users have to set gamma (cosab) in an input-file, not alpha (cosbc) or
> beta (cosac).
>
>
>
> Regards,
>
> Satomichi
>
>
>
>
>
> 差出人: Paolo Giannozzi
> 送信日時: 2017年5月2日 23:52
> 宛先: General discussion list for Quantum ESPRESSO developers
> 件名: Re: [Q-e-developers] ibrav = 5, in INPUT_PW.def
>
>
>
> Hi
>
>
>
> ibrav=5 is the rhombohedral (or trigonal) lattice, having the three
>
> angles alpha=beta=gamma/=90. Is there any rule or tradition according
>
> to which such angle should be called gamma instead of alpha?
>
>
>
> Paolo
>
>
>
>
>
> On Mon, May 1, 2017 at 8:25 AM,  <nisihara225 at gmail.com> wrote:
>
>> Dear QE-developers,
>
>>
>
>>
>
>>
>
>> INPUT_PW.def says that celldm(4) = cos(alpha) when ibrav = +-5.
>
>>
>
>> However, it may be celldm(4) = cos(gamma) to be correct.
>
>>
>
>>
>
>>
>
>> Regards,
>
>>
>
>> Satomichi Nishihara
>
>>
>
>>
>
>>
>
>>
>
>> _______________________________________________
>
>> Q-e-developers mailing list
>
>> Q-e-developers at qe-forge.org
>
>> http://qe-forge.org/mailman/listinfo/q-e-developers
>
>>
>
>
>
>
>
>
>
> --
>
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>
> Phone +39-0432-558216, fax +39-0432-558222
>
> _______________________________________________
>
> Q-e-developers mailing list
>
> Q-e-developers at qe-forge.org
>
> http://qe-forge.org/mailman/listinfo/q-e-developers
>
>



-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222