Re: [ccp4bb] Merging statistics and systematic absences

2011-01-24 Thread Ronald E Stenkamp
Maybe counting reflections is dull and boring, but doesn't it make you wonder sometimes when two programs read the same file and end up with different reflection counts? What sophisticated mathematics or logical conditions make it such that progams can't mimic adding machines? What else are t

Re: [ccp4bb] Merging statistics and systematic absences

2011-01-24 Thread Eleanor Dodson
I absolutely agree with Phil. However I think it is very important NOT to remove systematic absences before scala. There are many cases of mis-assigned space groups where "systematic absences" are misleading - due to NC translation or bad measurement or whatever Eleanor On 01/24/2011 09

Re: [ccp4bb] Merging statistics and systematic absences

2011-01-24 Thread Phil Evans
My immediate response to this is that anyone worrying about the number of reflections should get out more. More seriously, is assessing the quality of measurements then multiple observed measurements of systematically absent reflections should agree within their error estimates and (ideally) ha

[ccp4bb] Merging statistics and systematic absences

2011-01-24 Thread Graeme Winter
Dear ccp4bb, I had an interesting question from a xia2 user last week for which I did not have a good answer. Here's the situation: - spacegroup is P212121, which was specified on the command-line - xia2 processes this as oP, assigns the spacegroup as P212121 before running scala -> generates m