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Need references for MiniMax fitting
Message #1 Posted by Namir on 6 Sept 2006, 12:42 p.m.

Hi All,

Valentin Albillo has published on his web site an HP-71B BASIC program that calculates the minimax coefficients of polynomials that pass through a discrete set of data. As I find myself interested in the algorithms used to evaluate basic transcendental functions, Valentin's approach comes across as very practical and useful. He provides a minimax polynomial that is very easy to evaluate.

I would like very much to obtain references for the algorithms behind the minimax polynomial fit. Links to web sitss or references to books are most appreciated.

Namir

Edited: 6 Sept 2006, 9:35 p.m.

      
Re: Need references for MiniMax fitting
Message #2 Posted by Valentin Albillo on 8 Sept 2006, 8:26 a.m.,
in response to message #1 by Namir

Hi, Namir:

    Thanks a lot for your kind remarks and your interest in my HP-71B Minimax Polynomial Fit program (freely downloadable in PDF format from my HP calc web site).

    These references might prove useful to you as a start:

    • Ref. 1 (PDF document)

    • Ref. 2 (PDF document)

    • Ref. 3 (PDF document)

    • Ref. 4 (Web site, theory and plenty of useful examples, with graphics)

Best regards from V.

            
Re: Need references for MiniMax fitting
Message #3 Posted by Namir on 8 Sept 2006, 11:12 a.m.,
in response to message #2 by Valentin Albillo

Excellent Valentin. Many many thanks for these references. I have tried coding (using Excel VBA so far) different methods to evaluate e^x, the basic trig functions and their inverses. The minimax polyomial that you showed in a previous post is the most practical for a handheld calculator (as an exercise of course). I have used the approximation by summing the products of constants coefficients with shifted Chebyshev polynomials. While they work ok in VBA (or any other high-level langauge), they are no practical to implement on a vintage programmable calculator like the HP-67.

Again, thanks for the references.

Namir

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