Category Archives: AlgLib

Fitting high order polynomials

Posted on 04/02/2011 by dougaj4

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

Complex Numbers and Solving Quartic Polynomial Equations

Posted on 19/09/2010 by dougaj4

It was recently pointed out to me that the User Defined Function (UDF) for solving quartic polynomial equations presented in this post returned an error for some input values.  In tracking down the source of the error I decided that it … Continue reading →

Posted in AlgLib, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 2 Comments

Eval.xls and the ALGLIB integration functions.

Posted on 11/09/2010 by dougaj4

In a comment on a previous post on numerical integration I mentioned that I might implement the ALGLIB integration functions using the same technique, that is using the VBA Evaluate function to evaluate functions entered as text in the spreadsheet.  Well … Continue reading →

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

Route Map …

Posted on 29/08/2010 by dougaj4

… so we know where we are going. I’ll be starting several, to some extent interlinked, new themes in this blog over the coming weeks.  Firstly VBA Classes.  Regular readers may have noticed that my VBA code tends to be … Continue reading →

Posted in AlgLib, Concrete, Excel, Finite Element Analysis, Frame Analysis, Link to dll, Maths, Newton, VBA | Tagged , , , , , | 4 Comments

2D Spline Interpolation with ALGLIB

Posted on 20/08/2010 by dougaj4

I have updated the ALGLIB Spline and Matrix Function spreadsheet to include 2D interpolation of tabular data, including both linear and cubic spline interpolation.  The spreadsheet including the new functions with full open source code may be downloaded from AL-Spline-Matrix03.zip … Continue reading →

Posted in AlgLib, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , | 6 Comments