On Mon, Aug 30, 2021 at 08:44:03PM +0100, Kay Diederichs wrote: > The following sentences (which are somewhat difficult to understand > for me) in https://www.ccp4.ac.uk/html/freerflag.html appear to > document that: "The FreeR_flag is randomly and uniformly distributed > reflexion-by-reflexion, but, additionally, if the keyword NOSYM is not > set, all reflections that are equivalent by the symmetry of the point > group of the twin lattice (assuming the data is twinned), obtain the > same flag. This includes both the possibility of merohedral and > pseudomerohedral twinning. In the latter case, the obliquity parameter > can be set using the keyword OBL." > > I wonder since which CCP4 version (or date) this is the default > behaviour.
Hi Kay, I believe it has been default since October 2015 but I'm not sure which version of CCP4 it was. 6.4 probably. In the previous version (6.3, I think), the default was to check the twinning (pseudo) symmetries only, but not the point group symmetries. The keyword NOSYM is there to retain the old behaviour of the program, which didn't check any symmetries. I'll try to improve the doc to make it clearer. Thanks for the feedback. Best wishes, Ville This email and any attachments are intended solely for the use of the named recipients. If you are not the intended recipient you must not use, disclose, copy or distribute this email or any of its attachments and should notify the sender immediately and delete this email from your system. UK Research and Innovation (UKRI) has taken every reasonable precaution to minimise risk of this email or any attachments containing viruses or malware but the recipient should carry out its own virus and malware checks before opening the attachments. UKRI does not accept any liability for any losses or damages which the recipient may sustain due to presence of any viruses. ######################################################################## 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/
