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562. AP: A General Fitting Program for Resolution of
Complex Profiles
by M. A. Raso, J. Tortajada, D. Escolar and F. Acción, Departamento Química-Física(Espectroscopia), Facultad CC. Químicas, Universidad Complutense, 28040 Madrid, España AP is an interactive, conversational, general-purpose program to fit experimental profiles to a set of theoretical distribution functions. The functions implemented are: Gaussian, Lorentzian, Gauss x Lorentz and log-normal (asymmetric). Moreover, the program has been developed in such a way as to be easily extended to any other function. Fitting is carried out by the least-squares procedure, employing Newton's method in the search of the minimum of squares of deviations. This method has been modified with several optimization criteria to avoid the nonconvergence problem.The algorithm and intelligent handling of these criteria are described in ref. 1. Input instructions and operating procedures are detailed in the documentation and in the COMMENT cards within the program, especially in the main input routines: LECESP, PAROPT and LECPAR. Sample decks and associated output of two examples are provided. The selected examples are two theoretical profiles obtained as a sum of three Lorentzian and three log- normal profiles, respectively. Fitting procedure of these profiles illustrates the common use of optimization criteria. The first example shows the necessity and usefulness of the BLOCK OPTIMIZATION criterion.The second explains the FIXED BAND criterion.The way to estimate the initial approximations of parameters is described in ref. 2. __________ References: 1. M. A. Rasso, J. Tortajada, D. Escolar and F. Acción, Comput. Chem., 11, 125 (1987). 2. J. Tortajada and F. Acción, J. Mol. Struct., 142, 263 (1986). __________ FORTRAN 77 (VAX 11/750) Lines of Code: 1865 |