A general Fourier program for X-ray crystal-structure analysis which utilizes the Cooley-Tukey algorithm

A computer program utilizing the Cooley-Tukey algorithm for rapid Fourier transformation is described. It has the following main features: (1) Fortran language compatible with most present day computers (the program was tested on Univac 1106/8, IBM 360, CDC 6600) is used; (2) limited core-storage is required (30,000-40,000 words); (3) except for the electron-density output, no auxiliary storage is required; (4) all space groups can be treated without any modification in the program; in every case only the independent reflections must be supplied; (5) repetitive syntheses, such as are required in working with direct multi-solution methods, can be carried out; (6) automatic search for the electron-density peaks, calculation of the distances between them and direct drawing of the structure on the computer printout are provided.