Tag Archives: UDF

ALGLIB linear and polynomial fitting functions

As promised here: Fitting high order polynomials this post presents details of four Excel User Defined Functions (UDFs) linking with ALGLIB functions for least squares fitting of linear and polynomial functions.  The new functions are: AL_Linest: AL_LinestCW: AL_PolyFit: and AL_PolyFitCW: These functions have been added … Continue reading

Posted in AlgLib, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 5 Comments

Fitting high order polynomials

This post is a follow up to Using LINEST for non-linear curve fitting and the following comments from Scott Rogers and Lori Miller.  Scott found that he was getting different results from Linest and the xy chart trend line for polynomials of … Continue reading

Posted in AlgLib, Charts, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , | 31 Comments

Finding all range names in a specified range

Another useful little snippet from Eng-tips. There was a question regarding how to list all the range names applied to a specified cell.  Forum members electricpete and MintJulep came up with a short macro to do the job, which I have … Continue reading

Posted in Excel, UDFs, VBA | Tagged , , , | 2 Comments

Evaluating higher order polynomials …

… and a better solution for quadratics. Having written a better solver for high order polynomials, that raises a few other issues.  The error in the roots found by the RPolyJT was checked by simply substituting each root as the … Continue reading

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 4 Comments

Solving higher order polynomials

The Quartic spreadsheet presented here previously (most recently here) uses algebraic techniques to provide an “exact” solution to polynomial equations of up to fouth order.  For polynomials of higher order there is no general algebraic solution, and numerical methods are … Continue reading

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 12 Comments