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# Category Archives: AlgLib

## 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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## Update to AL-Spline-Matrix

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 AlgLib, Cubic spline, Excel, spline curve fitting, UDF, VBA, weights and constraints
1 Comment

## Using Alglib least-squares solvers

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 AlgLib, Excel, Levenberg Marquardt, lsfit, minlm, Numpy, Python, SciPy, UDF, VBA, xlwings
2 Comments

## Evaluating text and calling Python functions from Excel with xlwings

The Alglib spreadsheet presented here includes functions to evaluate formulas entered as text on the spreadsheet, or to call specified Python functions. I have now added a user defined function (UDF) that will perform either of these operations (xl_CallFuncD), and added … Continue reading

Posted in AlgLib, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings
Tagged AlgLib, call Python functions, evaluate text strings, Excel, Numpy, Python, SciPy, UDF, VBA, xlwings
1 Comment

## Excel to Alglib via xlwings

The Alglib library provides many valuable numerical analysis routines, but the VBA version is no longer actively maintained. The latest versions are available in C++, C#, and Python, of which the Python version (in conjunction with xlwings) provides the easiest interface … Continue reading

Posted in AlgLib, Curve fitting, Excel, Link to Python, Maths, Newton, Numerical integration, UDFs, VBA, xlwings
Tagged AlgLib, Cubic Spline functions, curve fitting, Excel, Higher order polynomials, Matrix Functions, Python, UDF, VBA, xlwings
12 Comments