I suspect the problem is that sftools hasn't been modernised to alter all the cell dimension records used in current MTZ files. I can't remember right now but maybe the DCELL command in cad might fix it.
Randy Read ---- Randy J. Read > On 2 Oct 2013, at 17:13, wtempel <wtem...@gmail.com> wrote: > > Hello, > I would like to expand a reflection data set in mtz format from C2221 to P21. > The purpose is to obtain consistent R-free flags based on a structure already > refined in C2221 for a related data set that I suspect is pseudo-C2221 but > "real" P21. > > Primitive cell dimensions are: 37.6 126.1 40.61 89.99 117.6 90.01, > C-centered: 37.6 71.99 126.1 90 89.99 90.01 > pointless provides the following matrix: > <pointless> > Reindex operator from input cell to lattice cell: [h,h+2l,-k] > > h' = ( h k l ) ( 1 1 0 ) > ( 0 0 -1 ) > ( 0 2 0 ) > > </pointless> > In sftools, I loaded the C2221 data set and did > > sftools$ reindex matrix 1 0 0 0 0 -1 -.5 .5 0 > > with the transposed (to account for the presumably inverted order of factors > in the program?) inverse matrix of the one listed above with the aim of > restoring the primitive asymmetric unit. > I was encouraged seeing sftools report new cell dimensions matching the > expected primitive cell. > Then I did > > sftools$ expand 4 > > I expected now to have a "workable" P21 version of my C2221 data set, but > molecular replacement (MOLREP) with my C2221 model failed to place even a > single copy of the model. > Thus, I must have misused sftools by issuing commands that were either wrong > or in the wrong order or my application of linear algebra was mistaken. > Any ideas out there? > Thanking you in advance, > Wolfram Tempel
