Title of program: SROCASE data related to the diffuse scattered intensity [1] in diffraction patterns and to reconstruct the patterns. Thus, from Catalogue number: ACKN the diffraction data the Cowley -Warren s.r.o. parameters [2] are estimated and the clusters that satisfy these coeffi-Program obtainable from: CPC Program Library, Queen's cients are obtained by the probability variation method University of Belfast, N. Ireland (see application form in this (PVM) [3]. issue) Method of solution Computer: UNIVAC 1106;Installation: Computer Centre, To determine the s.r.o. coefficients aia Monte Carlo integra-Univ. of Tessaloniki tion was performed over a domain D defined in such a manner that at a point x ED the integrand function has a value given Operating system: EXEC8 by the diffraction data. The PVM requires the solution of a set of simultaneous Programming language used: FORTRAN IV nonlinear equations by the Newton-Raphson method. Application of this method leads to the solution of a system of High speed storage required: 9 K linear equations by the Gauss method. No. of bits in a word: 36 Restrictions on the problem The determinant of the simultaneous linear equations must overlay structure: none be different from zero. Typical running time No. of magnetic tapes required: none The time to calculate the first 8 s.r.o. parameters and the maximum probability and to print a diffuse intensity profile Other peripherals used : card reader, printer is 232 sec. The for time each additional diffuse intensity profile is 84 sec. No. of cards in combined program and test deck: 555 Unusual features of the program Card punching code: EBCDIC By modifying FUNCTION DOMAIN other diffuse intensity data may be reproduced.