Oh – I seemed to have diverted Frank’s thread. Fortunately most languages themselves are highly redundant, with following characters and words being quite predictable. The entropy and redundancy of English language was analysed by Shannon (with the help of his wife) and he obtained figures of about 1 bit per character rather than log base 2 (27), a redundancy of around 75%. I guess this redundancy helps us put things in context. However, in order to avoid future misunderstandings, I would like to suggest that further communications with CCP4BB be done in Latin which I believe has less ambiguity. I hope people will adopt this helpful suggestion.
OK – perhaps not a good idea. More relevant to Frank’s question, I was referring to cases where, for a particular reflection, the path of x-rays through the crystal was altered to average out systematic errors. What type of systematic errors would be mitigated by this? There is one potential addition to the list (absorption errors, detector calibration) I produced but it applies to synchrotron sources rather than the type of x-ray source used in the Acta D paper. I will let others have a think before suggesting it. Colin
