[Pw_forum] A bug in the pp.x?

[zhaohscas]

>Hi chopstick ;-),

Aha, I'm using both forks and chopsticks once in a while.

>>  In the abobe case, the e1 \bot e2, and e2 \bot e3, but e1 isn'
>>  perpendicular to e3.  So, this will violate orthogonal condition.
>
>You are right: the actual check performed by the code is:
>  e_i \cdot \e_j > 1.d-6
>which wrongly allows non-orthogonal vectors if their pairwise scalar
>products are negative. Thank you for reporting, it will be fixed in the
>next release.

But, in my mind, as for the study of the distribution of the charge density, we generallly want to have the distribution w.r.t a specific miller plane.  In the periodic crystal system, this can be represented on the plane determined by a parallelogram whose two sides are the corresponding primitive plane vectors.  If we consider this requirement, I think we should use miller plane vectors to contruct the grid, which are not always perpendicular indeed.  Under the above consideration,  the orthogonal condition will be not so good.

Yours sincerely,
Hongsheng.

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