Hi Xuanxuan,

This:


from cctbx import miller
import cctbx
from cctbx import crystal

ms = miller.build_set(
    crystal_symmetry=crystal.symmetry(
        space_group_symbol='Fd-3m',
        unit_cell=(5.4307,5.4307,5.4307,90.00,90.0,90.00)),
    anomalous_flag=False,
    d_min=0.4)

for hkl in ms.indices():
    print hkl

gives:

(0, 2, 2)
.
.
.
(1, 3, 3)

etc

2,2,0 is related by symmetry to 0,2,2

HTH-P


On 5 December 2017 at 01:01, 李选选 <lixx11@csrc.ac.cn> wrote:

Dear cctbx developers,

I’m Xuanxuan, and I’m using cctbx to develop a crystallography-related algorithm. Recently, I found there is something wrong when I use miller package to generate miller indices for given space group and unit cell parameters. Maybe it’s my mistake, or it’s a bug.

Here are some details. I just use the following code to generate a list of miller indices for a Fd-3m crystal.

ms = miller.build_set(
    crystal_symmetry=crystal.symmetry(
        space_group_symbol='Fd-3m',
        unit_cell=(5.4307,5.4307,5.4307,90.00,90.0,90.00)),
    anomalous_flag=False,
    d_min=0.4)

And I found some reflections are missing, like 220, 311, which should exist according to the reflection conditions listed in this page http://img.chem.ucl.ac.uk/sgp/large/227az2.htm. 

Looking forward to your response.

Thanks,
Xuanxuan


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P.H. Zwart
Staff Scientist
Molecular Biophysics and Integrated Bioimaging &
Center for Advanced Mathematics for Energy Research Applications
Lawrence Berkeley National Laboratories
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Cell: 510 289 9246

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