Generic macro to generate constraints

U [atoms] A Site or xyz [atoms] A Same group [n=2 atoms]

This is a generic macro to generate constraints.

The same group or non-crystallographic symmetry constraint makes two or more groups identical and linked through a transformation matrix, refined as a shift and 3 Euler angles. If two atoms are given, they must belong to two identical fragments; Olex2 will then try to match the fragments containing the atoms and automatically generate the constraint. In more generic/complex cases the user has to provide the number of groups to generate the constraint for and also the selection which matches atoms in the fragments.