ALTER: eclectic management of molecular structure data.

ALTER is a computer program written to facilitate easy conversion between different representations of molecular structure data. The program functions as a file converter, data generation engine, and through the creation of control or input files, as an interface to other programs. The main aspects of program function--the reading and writing of files; coordinate transformation; data reorganization: structure building; data abstraction, including the generation of a wide variety of topological indices and constitutional descriptors; and display--are described in appropriate detail.