crystal_system: Crystal system corresponding to given space group.
Description
Crystal system corresponding to given space group.
Usage
crystal_system(gn)
Value
A character string, the name of the crystal system associated
with the given space group. If the input integer does not correspond
any existing space group, the function returns NULL and throws a
warning.
Arguments
gn
A natural integer (1,2,3,...). the space group number.