Hello I guess you are using 5.5. In this version in the beginning twin fractions are just initial values. They need to be refined. This are potential twin operators. Further down in the log file there should be Rmerge for each twin operator and estimated twin fractions. What are they? Can you send me full log file?
One warning about twin refinement: In the beginning twin refinement may give wrong twin fractions. And perhaps before starting twin refinement you need to do refinement without twin (but select you reflections to reflect twin operators, i.e. free reflections should obey twin relationship). Regards Garib On 13 Oct 2010, at 21:33, Arnon Lavie wrote: > Hello: > > I am puzzled (probably shows my lack of understanding) by a REFMAC output > using the TWIN option. My data set is in space group 145 (P32), with a > twinning factor (according to the twining server) of ~ 40% along a*,b*. In > this space group there are three possible twinning operators, but only this > one shows a significant value. > > When refining with REFMAC, the program reports 4 twin domains: Here is the > relevant output. > > The number of twin domains = 4 > Twin domains ((pseudo)merohedral only): > Twin domain 1 with operator: " 1.000H, 1.000K, L" and with initial > fraction = 0.318 > Twin domain 2 with operator: "-1.000H, 1.000H+1.000K, -L" and with > initial fraction = 0.227 > Twin domain 3 with operator: "-1.000H, -1.000K, L" and with initial > fraction = 0.227 > Twin domain 4 with operator: "-1.000H-1.000K, 1.000K, -L" and with > initial fraction = 0.227 > --------------------------------------------------------------- > > So my question: why 4 twin domains? My understanding from the twinning server > is that there are only two twin domains, with a relative abundance of 40:60. > > Thanks. > > Arnon > > -- > *********************************************************** > Arnon Lavie, Professor > Dept. of Biochemistry and Molecular Genetics > University of Illinois at Chicago > 900 S. Ashland Ave. > Molecular Biology Research Building, Room 1108 (M/C 669) > Chicago, IL 60607 > U.S.A. > Tel: (312) 355-5029 > Fax: (312) 355-4535 > E-mail: la...@uic.edu > http://www.uic.edu/labs/lavie/ > ***********************************************************
