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# Category Archives: Arrays

## Cubic splines with jagged data

A cubic spline provides a good approximation to a smooth curve, and alternative versions are available for free download (see Daily Download 22: Splines and Curves, Update to AL-Spline-Matrix, and xlwSciPy 1.09 – update for xlwings 0.10 and Scipy 0.18.1), but if … Continue reading

Posted in Arrays, Beam Bending, Concrete, Curve fitting, Excel, Newton, UDFs, VBA
Tagged CSplineA, Cubic splines, Excel, fitting jagged data, MSplineA, UDF, VBA
2 Comments

## Brent’s Method; Update and Examples

Has the free software at this site saved you time and/or money? If so, please contribute to the Raw Impact charity group providing practical help to poor communities in Cambodia: Everydayhero – Cambodia 2018 All contributions gratefully accepted. Contributions are … Continue reading

Posted in Arrays, Excel, Maths, Newton, UDFs, VBA
Tagged Brents method, Excel, inverse quadratic, iterative solution, Maths, UDF, VBA
1 Comment

## Setting up UDF Applications

Following a recent comment, this post looks at setting up a user defined function (UDF) on a blank worksheet, using the ConBeamU function as an example. To use a UDF, the VBA code for the function must either be included … Continue reading

Posted in Arrays, Beam Bending, Excel, Finite Element Analysis, Newton, UDFs, VBA
Tagged ConBeamU, Excel, resize array functions, UDF, VBA
2 Comments

## Plotting Freeze-Thaw Data …

… or other irregular cyclic data. Another Eng-Tips question asked how to approximate ice area over a freeze-thaw cycle using a function based on a sine or cosine curve. The screen-shot below shows three alternatives: Using built in Excel functions requires … Continue reading

Posted in Arrays, Curve fitting, Excel, Maths, Newton, UDFs, VBA
Tagged cyclic data, Excel, Freeze-thaw curve, sigmoid curve, UDF, VBA
1 Comment

## Indexing NumPy arrays with floats …

… now you can’t. I recently updated to the latest version of NumPy (1.12.1), and today I discovered that some of my spreadsheets using NumPy arrays (via xlwings) were returning errors like: IndexError: only integers, slices (`:`), ellipsis (`…`), numpy.newaxis … Continue reading

Posted in Arrays, Excel, Link to Python, NumPy and SciPy, UDFs, VBA
Tagged Float index, IndexError, Numpy, Python, VBA, xlwings
2 Comments

## The meaning of = in Python

In VBA, if you have an array named a and a variant named b, then the statement “b = a” creates a new array b with the same size and values as a. If the values of either a or b are subsequently changed, the values of the … Continue reading