I recall that this has been discussed, more than once, on the ccp4-dev board and quite sensible solutions provided to this, for instance the inclusion of a one-character flag which would indicate the level of correctness of the spacegroup information - along the lines of
L => Bravais lattice correct P => pointgroup correct E => spacegroup or enantiomorph S => spacegroup is correct I can't find the appropriate email as it is buried in the mists of time, so the particular characters here may be different to those proposed. However, the idea was a sound one. This would need to go into the CCP4 MTZ library of course... And would be a very valuable addition. Cheers, Graeme -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Phil Evans Sent: 09 November 2007 13:54 To: [email protected] Subject: Re: [ccp4bb] pointless (1.2.0) and enantiomorphic SG's I agree On 9 Nov 2007, at 13:50, Eleanor Dodson wrote: > As I often say!!! The mtz format should carry point group and > alternate SGs - then be upgraded when youknow the correct SG.. > > Eleanor > > Phil Evans wrote: >> It just picks the first in the list, to store in the output MTZ file, >> which can only handle one (92 < 96) Phil >> >> >> On 8 Nov 2007, at 22:26, Bryan W. Lepore wrote: >> >>> when pointless (1.2.0) finds enantiomorphic SG's, what is the >>> criterion for 'Selecting' one over the other? >>> >>> e.g. i ran pointless on some tetragonal data, and the enantiomorphs >>> SG92/SG96 are selected as strong candidates >>> >>> Spacegroup TotProb SysAbsProb Reindex >>> Conditions >>> <P 41 21 2> ( 92) 0.956 0.956 00l: >>> l=4n, h00: h=2n (zones 1,2) >>> <P 43 21 2> ( 96) 0.956 0.956 00l: >>> l=4n, h00: h=2n (zones 1,2) >>> >>> ... then pointless reports : >>> >>> Selecting space group P 41 21 2 as solutions are enantiomorphic >>> Best Solution space group P 41 21 2 >>> >>> ... is that b/c pointless can only report one, and SG92 came up >>> first? >>> >>> -bryan >> >> >
