[Pw_forum] disagreement of *.in and *.out file in VCSexample

[Stefano de Gironcoli]

Dear Y.C. Cheng ,
    when ibrav = 0 (your case) the Bravais lattice vectors are read from 
the cell_parameters card not build from celldm's or a,b,c,...
    Only the value of a is used and converted to a.u. the other are not 
used...
    You are right that there is a bug in the sense that the code should 
stop and complain that you are providing not needed information (or set 
all celldm(2:5) to zero and continue)
    best regards.
          stefano de Gironcoli

程迎春 wrote:
> Dear Y. L. Xie,
>         I know celldm(2)=b/a,celldm(3)=c/a. My question is why  
> celldm(5) and celldm(6) are equal to 0.495175 in the input file, 
> but  equal to 0 in the out file.
>
>  
> 2008/5/26, Y.L. Xie <xylnew at gmail.com <mailto:xylnew at gmail.com>>:
>
>     在 2008-05-26一的 11:04 +0800，
>     =?GB2312?B?IrPM0620uiIgPHljY2hlbmcubmp1QGdtYWlsLmNvbT4=?=写道：
>     > Dear pwscf users:
>     Dear Y. C. Cheng,
>     >      I checked VCSexample in V4.0, and found a disagreement in the
>                         ^^^^^^
>     Please ALWAYS check manual  before ask question in this forum.
>
>     >  *.in and *.out. For example:
>     > In the As.vcs00.in <http://As.vcs00.in> file,the system is
>     defined as follows:
>     > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>     > +   ibrav = 0 ,
>     > +   A = 3.70971016 ,
>     > +   B = 3.70971016 ,
>     > +   C = 3.70971016 ,
>     > +   cosAB = 0.49517470 ,
>     > +   cosAC = 0.49517470 ,
>     > +   cosBC = 0.49517470 ,
>     > +
>     > +   CELL_PARAMETERS cubic
>     > +    0.58012956  0.00000000  0.81452422
>     > +   -0.29006459  0.50240689  0.81452422
>     > +   -0.29006459 -0.50240689  0.81452422
>     > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>     > In the beginning of As.vcs00.out file,the system is changed.
>     > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>     > +     bravais-lattice index     =            0
>     > +     lattice parameter (a_0)   =       7.0103  a.u.
>     > +     unit-cell volume          =     245.3705 (a.u.)^3
>     > +
>     > +     celldm(1)=   7.010336  celldm(2)=   1.000000  celldm(3)=
>     > 1.000000
>
>     celldm(2)=b/a,celldm(3)=c/a
>     Best
>
>     Xie Y.L.
>
>     > +     celldm(4)=   0.495175  celldm(5)=   0.000000  celldm(6)=
>     > 0.000000
>     > +
>     > +     crystal axes: (cart. coord. in units of a_0)
>     > +               a(1) = (  0.580130  0.000000  0.814524 )
>     > +               a(2) = ( -0.290065  0.502407  0.814524 )
>     > +               a(3) = ( -0.290065 -0.502407  0.814524 )
>     > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>     > a=3.70971016A -> celldm(1)=7.010336a.u. and celldm(2)=celldm(3)=1
>     > celldm(4)=cos(bc)=0.495175
>     > but why celldm(5),celldm(6)are equal to 0?
>     >
>     > --
>     > Y. C. Cheng
>     > Department of Phyics
>     > Nanjing University
>     > Nanjing 210093
>     > P. R. China
>     > Tel: 86-25-83592907
>     > Email: yccheng.nju at gmail.com <mailto:yccheng.nju at gmail.com>
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>
>
> -- 
> Y. C. Cheng
> Department of Phyics
> Nanjing University
> Nanjing 210093
> P. R. China
> Tel: 86-25-83592907
> Email: yccheng.nju at gmail.com <mailto:yccheng.nju at gmail.com>
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