Crunch2 is a program for the determination of sub-structures of anomalous scatterers or heavy atoms in macromolecular crystallography. Crunch2 is contained in the Crank suite and is available for download from the Crank web site.

Crunch is a fully developed and maintained version aimed at the ab initio solution of difficult small structures via the the implementation of a probabilistic approach involving Karle-Hauptman matrices. On the Crunch webpage, this program can be downloaded.