Hi Randy, > On 23 Feb 2024, at 11:49, Randy John Read <rj...@cam.ac.uk> wrote: > > Why would we want to impose an arbitrary restriction on users for this > relatively common scenario.
If the user has the unmerged data this can be imported into CCP4i2 via the data reduction task and merged in P1. How would you expand the merged data to P1 - using cad from a script? Perhaps this should be made possible in CCP4i2 after the merged data were imported. i2 already has a "Reindex or change spacegroup" task (using POINTLESS) but it won't do this: "FATAL ERROR: Specified SPACEGROUP P1 must belong to same crystal system and point group as the input space group P 41 21 2" > > Note that this kind of confusion between twinning and true symmetry will > mostly arise when the twin fractions are close to equal. Then: a) the > twin-related intensities should really be measurements of the same thing, and > you get more precise data by making them equal; b) the superimposed > diffraction patterns will obey the higher symmetry, although the spots might > start to split at higher resolution. > > I would also argue that, if the twin fractions are experimentally > indistinguishable from being equal, processing in higher symmetry and > expanding the data to the correct lower symmetry is the correct approach to > take for your final data set. That's a fair comment. In that case would you then report the merging statistics for the higher symmetry data in "Table 1" and note that the merged data were subsequently expanded to the correct lower symmetry? Huw ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
