-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Wolfram Tempel,
there might be some confusion about terms. It is correct that xscale scales several data sets together. However, in crystallography, 'merging' might be the better term for this process. Crystallographic 'Scaling' is far more complicated than 'merging'. It applies correction factors which try to make up for experimental errors in your data set. These corrections include the sigma-values, which is particularly important for experimental phasing. In that respect it can actually hamper the data quality if you (crystallographically) scale your data twice, although the effect is rather subtle. CORRECT carries out these corrections, hence CORRECT scales your data set, while XSCALE does not repeat this step - it "only" merges your data in the sense that it puts your data on a common scale. This is the application of a not too difficult mathematical formula (which is listed in the xds wiki, but I don't remember the URL). Regards, Tim On 11/11/2014 10:07 PM, Sudhir Babu Pothineni wrote: > > http://strucbio.biologie.uni-konstanz.de/xdswiki/index.php/Xscale > > XSCALE > <http://www.mpimf-heidelberg.mpg.de/%7Ekabsch/xds/html_doc/xscale_parameters.html> > > is the scaling program of the XDS suite. It scales reflection files > (typically called XDS_ASCII.HKL) produced by XDS. Since the CORRECT > step of XDS already scales an individual dataset, XSCALE is only > /needed/ if several datasets should be scaled relative to another. > However, it does not deterioriate a dataset if it is "scaled again" > in XSCALE, since the supporting points of the scalefactors are at > the same positions in detector and batch space. The advantage of > using XSCALE for a single dataset is that the user can specify the > limits of the resolution shells. > > _Scaling with scala/aimless_ > > http://strucbio.biologie.uni-konstanz.de/xdswiki/index.php/Scaling_with_SCALA_%28or_better:_aimless%29 > > > > -Sudhir > > > *************************** Sudhir Babu Pothineni GM/CA @ APS 436D > Argonne National Laboratory 9700 S Cass Ave Argonne IL 60439 > > Ph : 630 252 0672 > > > > > On 11/11/14 14:42, wtempel wrote: >> Thank you Boaz. So if CORRECT can do a fully corrected scaling, >> are there no corrections that XSCALE might apply to XDS_ASCII.HKL >> data that are beyond CORRECT's capabilities? Wolfram >> >> >> On Tue, Nov 11, 2014 at 3:05 PM, Boaz Shaanan >> <bshaa...@bgu.ac.il <mailto:bshaa...@bgu.ac.il>> wrote: >> >> Hi, >> >> I actually choose the option 'constant' further down in the >> aimless gui but I guess the effect is similar to 'onlymege'. >> >> Boaz >> >> /Boaz Shaanan, Ph.D. Dept. of Life Sciences Ben-Gurion University >> of the Negev Beer-Sheva 84105 Israel >> >> E-mail: bshaa...@bgu.ac.il <mailto:bshaa...@bgu.ac.il> Phone: >> 972-8-647-2220 Skype: boaz.shaanan Fax: 972-8-647-2992 or >> 972-8-646-1710 / // // / >> >> / >> >> ------------------------------------------------------------------------ >> >> *From:* CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK >> <mailto:CCP4BB@JISCMAIL.AC.UK>] on behalf of wtempel >> [wtem...@gmail.com <mailto:wtem...@gmail.com>] *Sent:* Tuesday, >> November 11, 2014 9:50 PM *To:* CCP4BB@JISCMAIL.AC.UK >> <mailto:CCP4BB@JISCMAIL.AC.UK> *Subject:* [ccp4bb] To scale or >> not to scale: XDS_ASCII.HKL input to POINTLESS/AIMLESS >> >> Hello all, in a discussion >> >> <https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind1307&L=CCP4BB&H=1&P=186901> >> >> >> on this board, Kay Diederichs questioned the effect of scaling >> data in AIMLESS after prior scaling in XDS (CORRECT). I >> understand that the available alternatives in this work flow are >> to specify the AIMLESS ‘onlymerge’ command, or not. Are there any >> arguments for the preference of one alternative over the other? >> Thank you for your insights, Wolfram Tempel >> >> >> >> > > - -- - -- 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) iD8DBQFUYzT7UxlJ7aRr7hoRAuO2AJ9P3kJAjP+8wWjXRvkZwgDs9UOo3ACfb1En 67VgyyqCTX6j5vOz3xMVwqE= =ooTC -----END PGP SIGNATURE-----
