Category Archives: Charts

Iterative solvers and arrays

Posted on October 21, 2018 by

A recent thread at Eng-Tips was looking for a solution to the problem described  below: The solutions to this problem described below can be downloaded from: ItSolve.zip and xlScipy3.zip The ItSolve.xlsb spreadsheet contains a user defined function (UDF) to solve iterative … Continue reading →

Posted in Arrays, Charts, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings | Tagged , , , , , , , | 1 Comment

Arcs and arc-splines

Posted on August 17, 2018 by

I have added two user defined functions (UDFs) to the IP2 spreadsheet to generate coordinates for a single  arc, or a series of arcs connected (if necessary) by straight lines.  The new version may be downloaded from: IP2.zip As an example … Continue reading →

Posted in Animation, Charts, Charts, Coordinate Geometry, Drawing, Excel, Maths, UDFs, VBA | Tagged , , , , , , | 1 Comment

Plotting Charts With Gaps …

Posted on March 31, 2018 by

“How do you get VB6 to initialize doubles with +infinity, -infinity and NaN”… and various sorts of Not a Number. Back in 2012 (When is an xy chart not an xy chart) I concluded that it was not possible to … Continue reading →

Posted in Arrays, Charts, Charts, Excel, UDFs, VBA | Tagged , , , | 5 Comments

Using Matplotlib from Excel with xlwings – update

Posted on May 7, 2017 by

In February 2016 I posted a spreadsheet with examples of linking to the Python Matplotlib library with xlwings.  Since then updates to xlwings required some changes to the python code, specifically plot.show has been replaced with pictures.add. The spreadsheet has … Continue reading →

Posted in Charts, Charts, Excel, Link to Python, Newton, NumPy and SciPy, VBA | Tagged , , , , , , , | Leave a comment

More on trend line equations on line charts

Posted on April 27, 2017 by

In the previous post we saw that if a trend line equation is added to a line chart it will return the wrong coefficients if the x values are not a continuous sequence of integers, starting at 1 (click on … Continue reading →

Posted in Charts, Excel, Maths, Newton | Tagged , , , , | 1 Comment

Displaying trend line equations on line charts

Posted on April 16, 2017 by

This post is prompted by a recent comment at Using LINEST for non-linear curve fitting which found that the trend line formula displayed on a chart was totally different from that found using the Linest function. The problem was caused by using a … Continue reading →

Posted in Charts, Charts, Excel, Maths | Tagged , , , | Leave a comment

A mystery curve links to Jupyter

Posted on July 16, 2015 by

Reviewing some of my less visited links recently, I was intrigued by a post at The Math Less Travelled: The previous post at the site provides more details of the source of the curve, and some links to an interactive … Continue reading →

Posted in Charts, Charts, Excel, Maths, Newton | Tagged , , , , , , | 2 Comments