On 29 May 2012, at 15:02, Ian Tickle wrote:
> Phil,
>
> On 29 May 2012 14:08, Phil Evans <[log in to unmask]> 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
|