The MULTI command allows a multiple set of structures to be
read in for fitting. The filename specified for MULTI is a
`file of files' i.e. it contains a list of filenames which will be
read.
MULTI is used in place of REFERENCE and MOBILE to
read in a set of structure files. The first structure file is used as
a reference set for the first fitting stage, but the coordinates are
averaged after each fitting stage to derive an averaged template used
for subsequent fitting.
i.e. Given N files to fit, file 2 is fitted to file 1 and an averaged structure, A, is calculated, file 3 is then fitted to Aand a new average, A' is calculated. This continues until all Nstructures have been fitted. The whole procedure iterates until convergence (typically 3 or 4 cycles).
Progress and RMSds are reported at each iteration unless the QUIET
command is used.
The resulting fitted files are written with the MWRITE command.
Note that there is no ``reference'' set in the sense used for normal
2-structure fitting; fitted versions of all N files will be written
since the reference set is actually an averaged template.
When the MWRITE command is used, the output filenames are the
same as the input files, but with the extension replaced by that
specified in the MWRITE command. If no extension is specified,
then `.fit' will be used. If the input structure files contained no
extension, then the extension specified will be appended to the
filenames.
Note that since only the extension is changed when writing back the fitted files, you must have permission to write to the directory from which the original files were read.
Note that multiple structure fitting and zone interation can be very slow as these have been added to the earlier pair-wise fitting engine. An increase in speed needs a complete re-design of the code.