Ian, Ah! the old the row is the column depiction of matrices in CCP4 - ha had forgotten about that! Now at least the output makes sense and the caveat is to never use brackets.
Thanks to all replies!! Jens On Tue, 2012-01-31 at 10:17 +0000, Ian Tickle wrote: > On 31 January 2012 02:30, Jens Kaiser <kai...@caltech.edu> wrote: > > Hi all, > > we encountered an odd behaviour of REINDEX. > > > > Snip form logfile: > > > > Data line--- reindex HKL (h+l)/2, -k, (h-l)/2 > > Data line--- end > > > > Reflections will be reindexed, and unit cell recalculated > > > > Reindexing transformation: > > (h' k' l') = ( h k l ) ( 1.00000 0.00000 1.00000 ) > > ( 0.00000 -1.00000 0.00000 ) > > ( 0.50000 0.00000 -0.50000 ) > > > > Obviously, the first line of the matrix is not what we intended to > > create. > > > > inputting the transformation as HKL h/2+l/2, -k, h/2-l/2 > > produces the desired result: > > > > Data line--- reindex HKL h/2+l/2, -k, h/2-l/2 > > Data line--- end > > > > Reflections will be reindexed, and unit cell recalculated > > > > Reindexing transformation: > > (h' k' l') = ( h k l ) ( 0.50000 0.00000 0.50000 ) > > ( 0.00000 -1.00000 0.00000 ) > > ( 0.50000 0.00000 -0.50000 ) > > > > > > > > Admittedly, the documentation does not use any brackets in the examples, > > but i would expect REINDEX either to throw an error or treat (h+l)/2 > > like (h-l)/2 but not treat them in the way encountered. > > Jens > > Reindex is not treating (h+l)/2 any differently from (h-l)/2, they are > being treated identically, i.e. it is simply ignoring the brackets in > both cases (which is why expanding the expressions without brackets > works).. > > So (h+l)/2 is being treated as though you had specified h+l/2 and > (h-l)/2 becomes h-l/2. > > Don't forget that the rule for matrix multiplication is row-by-column, > not row-by-row! > > Cheers > > -- Ian
