Author Archives: dougaj4

Update to Glob_to_loc3 and Loc_to_glob3 functions

Posted on 30/05/2017 by dougaj4

Following a comment here I have updated the Glob_to_loc3 and Loc_to_glob3 functions to deal with some problems when the local longitudinal axis is parallel to the global Y or Z axes.  The IP2 spreadsheet, including the revised functions, can be downloaded from: … Continue reading →

Posted in Coordinate Geometry, Excel, Finite Element Analysis, Frame Analysis, Newton, UDFs, VBA | Tagged , , , , , , | 6 Comments

Working with milliseconds in Excel

Posted on 27/05/2017 by dougaj4

Edit 3rd Jan 2026: This download is not currently available. A recent post at Eng-Tips looked for a solution to problems with working with times in Excel, when time differences are required to the nearest millisecond. The problem is that although … Continue reading →

Posted in Computing - general, Excel, UDFs, VBA | Tagged , , , , , , | 1 Comment

Using Matplotlib from Excel with xlwings – update

Posted on 07/05/2017 by dougaj4

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 27/04/2017 by dougaj4

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 16/04/2017 by dougaj4

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