Just to be clear, the Pointless default setting (“CELL-BASED”), which has a<b<c for all primitive orthorhombic groups irrespective of which axes are screws, is the IUCr standard. Space groups such as P 2 21 2 are accepted by essentially all programs except XDS, which identifies it only as number 17, which is ambiguous. The advantage of keeping the CELL-BASED setting is that in most cases there is no need to reindex the data after the initial indexing, when the space group is determined either from systematic absences or by structure solution eg by MR, and reindexing may be confusing.
Of course if there is a real indexing ambiguity, eg a~=b, then a reference dataset is needed for consistency between datasets, either for XDS or Pointless - in the most common space group P 21 21 21 systematic absences don’t help, and they can be missing or unreliable. That said, it’s up to you which way you find less confusing - either work in the end Phil > On 10 Aug 2018, at 08:29, Kay Diederichs <kay.diederi...@uni-konstanz.de> > wrote: > > Tommi, > > one aspect that may be confusing is that XDS and POINTLESS by default have a > different way to describe the setting of orthorhombic space groups with 1 or > 2 screw axes > This seems relevant for this particular project, and is discussed in > https://strucbio.biologie.uni-konstanz.de/xdswiki/index.php/Pointless > In short, to make the POINTLESS setting compatible with that of XDS, you want > to use > SETTING SYMMETRY-BASED > in the POINTLESS input. XDSGUI does that for you. > > HTH, > Kay > > ######################################################################## > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
