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[Licence| Download | New Version Template] abfp_v1_0.gz(33 Kbytes)
Manuscript Title: POLYFIT: a package for polynomial fitting.
Authors: S.J. Sciutto
Program title: POLYFIT
Catalogue identifier: ABFP_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 52(1989)427
Programming language: Pascal.
Computer: IBM/370-4361.
Operating system: OSVS1.
RAM: 24K words
Word size: 32
Keywords: General purpose, Numerical analysis, Data handling, Fitting, Correlation, Error propagation.
Classification: 4.9.

Nature of problem:
Fitting a polynomial to a given data set is a problem appearing in most branches of experimental and theoretical physics.

Solution method:
With this package, the user can fit polynomials P(x) of arbitrary degree, with or without constraints, to a given set of points (Xn,Yn) n = 1,...N; N>1, using the least squares method. It is also possible to assign to each point a weight Omega n and/or an error -or fluctuation- Delta n to the respective Y n's. Two kinds of constraints can be specified: 1) Keeping fixed a certain subset of the polynomial's coefficients, and 2) Imposing that P(Xi q)= Eta q, q=1, ...Q, Q>0 for given points (Xi q, Eta q), q=1,...Q. The problems here presented can be reduced to a system of linear equations. The routines solve these systems using the well-known Gauss reduction technique. The package was written in a fully modular form, so as to allow the user to select just the necessary routines to solve any particular problem.

Running time:
1.25 sec for the test run.