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Category Archives: UDFs
LinEstGap with non-linear functions
The LinEstGap user defined function (UDF) allows the built-in Linest function to be used on data with empty cells or hidden rows, returning results that agree with the chart trend-line function, which automatically ignores blank cells and hidden data. It … Continue reading
Posted in Arrays, Curve fitting, Excel, Maths, Newton, UDFs, VBA
Tagged Excel, Exponential curves, Linest, Linest with gaps, Log curves, non-linear curve fitting, Polynomial curves, Power curves, UDF, VBA
1 Comment
DigitGraph Spreadsheet and WebPlot Digitiser
I have posted here previously a spreadsheet that allows XY data to be extracted from images of graphs, maps or other images of objects in a single plane: How to digitise a scanned image. I have updated the instructions for the … Continue reading
Posted in Charts, Charts, Computing - general, Curve fitting, Drawing, Excel, UDFs, VBA
Tagged DigitGraph, digitize scanned image, Excel, UDF, VBA, WebPlot Digitizer
5 Comments
Asymmetric Catenary Function
Back in 2009, I posted a user defined function (UDF) to generate a catenary curve, that could be used together with the Excel Solver to generate a curve of a specified span and sag: A catenary function Following a discussion … Continue reading
Posted in Coordinate Geometry, Curve fitting, Excel, Maths, Newton, UDFs, xlwings
Tagged Catenary, Excel, Solver, UDF, VBA
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Column buckling under multiple loads
Following another buckling discussion at Eng-tips I have modified my Frame4-buckle spreadsheet to allow input of multiple axial loads at any point along the column, along with any number of sections with different section properties. Background on the method used … Continue reading
Posted in AlgLib, Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Newton, UDFs, VBA
Tagged AlgLib, column buckling, Euler buckling, Excel, Frame Analysis, multiple load buckling, stepped column, tapered column, VBA, Vianello
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Python Traps
When converting existing VBA code to Python there are a number of obvious changes to the syntax that need to be made for the code to run at all, but there are also a number of not so obvious traps … Continue reading
Posted in Arrays, Excel, Link to Python, Newton, NumPy and SciPy, PyXLL, UDFs, VBA
Tagged Excel, for loop counters |, Numpy, Passing variables, Python, python traps, PyXLL, UDF, VBA
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Excel Dynamic Arrays
Previews of dynamic arrays in Excel have been available for some time through the “Insider” programme. They are now being published to general subscribers through Office 365 monthly updates: Further information is given at: Easier array formulas and Dynamic array … Continue reading
Posted in Arrays, Excel, UDFs
Tagged array functions, CSE array functions, dynamic arrays, Excel, UDFs, VBA
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A problem with integers in VBA
A recent question at Quora asked: “Why am I getting an overflow error in Excel VBA when doing a simple arithmetic calculation like str1 = 24*60*30 where str1 is a variant or long or double?” I hadn’t encountered that problem … Continue reading
