Hi Graeme This has nothing to do with Randy's 1986 paper on minimally-biased map coefficients from partial structures (which I assume is the one you're referring to) since as you said yourself these are experimental, not partial structure, phases. Rather, this is Blow & Crick's (1959) result where they showed that coefficients m*F with the centroid phase give the electron density with the least mean-square error over the unit cell. But maybe the error in the density is not something you need to worry about, since if the signal/noise ratio is sufficiently high the peaks will stand out against the background anyway?
Paul's solution looks like the best one (once tested!). Cheers -- Ian On 24 May 2012 10:38, <[email protected]> wrote: > Hi Tim, > > Thanks, this seems like a good plan. As I don't get to do much refinement I > have never really spent much time worrying about FWT, FOM etc. I should read > Randy's papers more I guess. > > Best wishes, > > Graeme > > BTW - does everyone have to confirm every message to the mailing list? > > > -----Original Message----- > From: Mailing list for users of COOT Crystallographic Software > [mailto:[email protected]] On Behalf Of Tim Gruene > Sent: 24 May 2012 10:31 > To: [email protected] > Subject: Re: --auto column labels > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi Graeme, > > So far I never noticed any difference between using or not using FOM into > account from a phs-file, so if you only want to display the resulting map > from shelxe DM I would not bother about whether this is mathematically > correct. > > I DON'T think FWT=F*FOM: as far as I understand FWT are the sigmaA weighted > amplitudes and I don't think shelxe calculates sigmaA weighted coefficients. > > Regards, > Tim > > On 05/24/12 10:47, [email protected] wrote: >> Hi Tim, >> >> A good answer, but I thought FWT = F * FOM? So this would not include >> the FOM's for the reflections? If I have this wrong that would be >> great. >> >> Thanks, >> >> Graeme >> >> -----Original Message----- From: Tim Gruene >> [mailto:[email protected]] Sent: 24 May 2012 09:46 To: >> Winter, Graeme (DLSLtd,RAL,DIA) Cc: [email protected] Subject: >> Re: --auto column labels >> >> Hi Graeme, why don't you name the column types FWT and PHWT as you >> convert the phs-file to mtz? >> >> You can also read in the phs-file directly given a cell, although I am >> not aware of an automated way. >> >> Cheers, Tim >> >> On 05/24/12 10:27, [email protected] wrote: >>> Hi Folks, >> >>> I would like to load a phased mtz file from shelxe / convert2mtz >>> automatically in coot: >> >>> (from mtzdmp) >> >>> * Column Labels : >> >>> H K L F FOM PHI SIGF FreeF_flag >> >>> * Column Types : >> >>> H H H F W P Q I >> >>> * Associated datasets : >> >>> 0 0 0 0 0 0 0 0 >> >>> I see from the manual I need: >> >>> --auto filename for auto-reading mtz files (mtz file has the default >>> labels FWT, PHWT) >> >>> Is there an easy way to join these up? I just want to be able to >>> inspect the map. I use this already to automatically show results >>> from refmac, which works very nicely indeed. >> >>> Many thanks, >> >>> Graeme >> >> >> > > - -- > - -- > Dr Tim Gruene > Institut fuer anorganische Chemie > Tammannstr. 4 > D-37077 Goettingen > > GPG Key ID = A46BEE1A > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.12 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iD8DBQFPvf/oUxlJ7aRr7hoRAnNbAKDbFMAUwqUGoijyV1JdjrS1xQDB/ACggTZ8 > UV1zCe/IdRwpeaeFhSydtxU= > =RyGN > -----END PGP SIGNATURE-----
