On 29 May 2012, at 15:02, Ian Tickle wrote: > Phil, > > On 29 May 2012 14:08, Phil Evans <p...@mrc-lmb.cam.ac.uk> wrote: >> NO do NOT invert the hand. If you do you will end up with left-handed >> helices etc > > Surely not if you take care to also change the signs of the anomalous > differences?
I suppose that's true (I think) but it's no harder to do it properly (ie preserving the hand > >> The alternative indexing systems all need to preserve the right-handed axis >> system imposed by the data integration program (eg k,h,-l) >> >> The ONLY time it is valid to invert the hand is if the indexing/integration >> program itself inverted the hand due to a bug (this has been know, but not >> for a long time) > > Assuming I've got the correct transformations and a.u. in P321 it's > only possible to re-index from the alternate setting if the hand is > inverted (and the anomalous data & any phase columns converted). > No the hand-preserving transformation in 321 is (k,h,-l) Phil > Cheers > > -- Ian
