Author Archives: dougaj4

Faster Ferns

Posted on 03/10/2010 by dougaj4

I have modified the fern input parameters in the spreadsheet presented in the previous post to match the layout used by Barnsley and others, so that examples such as those given at the Wikipedia article can be entered directly.  The … Continue reading →

Posted in Arrays, Charts, Charts, Drawing, Excel, Maths, Newton, VBA | Tagged , , , | 4 Comments

Plotting Ferns

Posted on 27/09/2010 by dougaj4

Over at Daily-Dose-of-Excel mrt has posted an interesting VBA version of a Matlab program that used an Iterated Transfer Function to plot a graph resembling a fern.  The original Matlab code came from Dr Tom Wood, and Michael’s VBA version works just fine, … Continue reading →

Posted in Arrays, Charts, Drawing, Excel, Maths, Newton, VBA | Tagged , , , , | 5 Comments

Working with FEM data and using the dictionary object

Posted on 26/09/2010 by dougaj4

This post features an Excel User Defined Function (UDF) to count the number of different element types (beams, plates, bricks and links) and the number of node restraints at each end of listed beams from a finite element model.  The … Continue reading →

Posted in Arrays, Excel, Finite Element Analysis, Newton, UDFs, VBA | Tagged , , , , , | 5 Comments

PyXLL Links

Posted on 20/09/2010 by dougaj4

This is really just a bookmark for me and anyone else who may be interested. “PyXLL is an Excel addin that enables functions written in Python to be called in Excel.” That’s all I know, but it looks interesting, and … Continue reading →

Posted in Computing - general, Excel, Link to dll, UDFs | Tagged , | 1 Comment

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 , , , , , , | 3 Comments