Multiple Structure Fitting
Keywords: ProFit

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Multiple Structure Fitting

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.

- Specifying Zones With Multiple Structure Fitting

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