Contents
FitUtil  Curve Fitting Utility APL+Win Workspace
OVERVIEW
General Utility Workspace for Curve Fitting.
DESCRIPTION
The main functions are FIT and TFIT. Both will perform 10 different curve fittings on a set of X and Y values. The function TFIT will removed the nonsignificatives points by performing a Student test on the data. The results are stored in a global nested variable called ∆FIT or ∆TFIT depending of the main function used. FIT and TFIT will present the results of the curve fittings in the APL session, the function SHOW will present them graphically using ∆FIT or ∆TFIT. It uses QPLOT developed by Jeff Koloseus and the APL2000 grid. The usage of the functions is as follow: x FIT y SHOW ∆FIT x TFIT y SHOW ∆TFIT The regressions performed are: 1. Linear: Y' = a + b×X 2. Exponential: Y' = a × exp(b×X) 3. Power: Y' = a × X*b 4. Logarithmic: Y' = a + b×ln(X) 5. Parabolic: Y' = a + b×X + c×X*2 6. Cubic: Y' = a + b×X + c×X*2 + d×X*3 7. Linear through origin: Y' = 0 + b×X 8. Parabolic through origin: Y' = 0 + b×X + c×X*2 9. Cubic through origin: Y' = 0 + b×X + c×X*2 + d×X*3 10.Weibull: Y' = a × exp(b×X*c) The first 9 curve fittings are a least square fit using the APL's domino operator. The Weibull regression is obtained by iterations and may not converge to a solution all the time.
EXAMPLES
Here is an example of what you can do:
(⍳10) FIT 2+4×⍳10
VERSION
May 2008  First Release of WS
DOWNLOAD
The workspace in APL+Win version 5 can be downloaded here: FitUtil.w3
INFORMATION
Original author: 
Pierre Gilbert 
Responsible: 

Email: 
<apgil AT SPAMFREE videotron DOT ca> 