Category Archives: UDFs

3D Intersections

Posted on 19/03/2011 by dougaj4

Following a discussion at the Eng-Tips Forum, I have written an Excel User Defined Function (UDF) to find the intersection point of two 3D line segments.  The UDF has been added to the IP2 spreadsheet, which is available for free … Continue reading →

Posted in Coordinate Geometry, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , | 7 Comments

Double Exponential Quadrature

Posted on 07/03/2011 by dougaj4

Graeme Dennes has updated his Tanh-Sinh Quadrature spreadsheet to include Double Exponential Quadrature.  His brief notes are given below, and more details and links to background information are included in the download file. ================================================================= Double Exponential Quadrature UDFs added to Tanh-Sinh Quadrature … Continue reading →

Posted in Excel, Maths, Newton, Numerical integration, UDFs, VBA | Tagged , , , , , | 1 Comment

Non linear regression – 2; ALGLIB functions

Posted on 05/03/2011 by dougaj4

The previous post looked at using the Excel Solver to fit a non-linear equation to a given set of data, using the least squares method.  This approach is reasonably convenient and straightforward, but it has a number of disadvantages: The … Continue reading →

Posted in AlgLib, Concrete, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , | 8 Comments

ALGLIB linear and polynomial fitting functions

Posted on 17/02/2011 by dougaj4

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

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