NAME
     CalcCluster - reduce number of structures

SYNOPSIS
     CalcCluster expr expr expr

DESCRIPTION
     Takes a bundle of superimposed structures and
     determines a smaller number of structures that
     represent the same bundle as well as possible. This is
     done by clustering similar structures into groups, and
     taking the "central" structure of each group.

     The command acts on all selected molecules and only
     considers the selected atoms of these molecules for
     the calculation.

     The first argument gives the desired number of
     structures. The second argument gives the minimal RMSD
     between two resulting groups, where the RMSD between
     two groups is defined as the maximal RMSD between a
     member of one group and a member of the other group.
     The third argument gives the maximal RMSD of two
     members of a group. Due to these restrictions, the
     number of calculated clusters can be different from
     the one given as first argument.

     The property "cluster" is set on all molecules that
     represent a group. From each group, the one with the
     smallest sum of RMSDs to all other members is chosen.
     A property (cluster1, cluster2, etc.) is also set for
     each member of every cluster.

     This command supports groups.

EXAMPLE
     CalcCluster 5 0.02 1

SEE ALSO
     SelectMol, SelectAtom, Group, Fit, MeanMol

DATE
     980817
