Category Archives: Newton

Update to AL-Spline-Matrix

Posted on 28/11/2017 by dougaj4

The AL-Spline-Matrix spreadsheet contains a large number of VBA user defined functions (UDFs) performing spline fitting and matrix operations, using the free and open source ALGLIB library. It was recently pointed out that the Excel interface code for the CSplineFitCW1da … Continue reading →

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

Composite Beam Spreadsheet Update 1.01

Posted on 04/11/2017 by dougaj4

Following a comment here, I have modified the Composite Beam spreadsheet to correct the stage 1 stresses forces in the reinforcement as listed in Columns 6 and 7, when the tensile face is the top.  The output has also been … Continue reading →

Posted in Beam Bending, Concrete, Excel, Newton, UDFs, VBA | Tagged , , , , , , , | 3 Comments

Hofstadter, Pahud, Bach

Posted on 08/10/2017 by dougaj4

The latest ACO concert series features the Swiss flautist Emmanuel Pahud (interview here). The performance included J.S. Bach’s 6 Part Ricercar, from The Musical Offering, which was the inspiration for the final dialogue in Douglas Hofstadter’s Godel, Esher, Bach: Achilles … Continue reading →

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Working with implied units – update

Posted on 30/09/2017 by dougaj4

Following comments at Eng-Tips I have added two examples with different procedures for evaluating ACI equations for the flexural tensile strength of concrete here.

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , , , , , | Leave a comment

Using Alglib least-squares solvers

Posted on 23/09/2017 by dougaj4

Following the last post on using the Python version of Alglib from Excel, via xlwings, this post looks in more detail at alternatives for fitting a non-linear function to a set of data, using the Levenberg-Marquardt method.  The spreadsheet with … Continue reading →

Posted in AlgLib, Curve fitting, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings | Tagged , , , , , , , , , , | 2 Comments