Tag Archives: Numpy

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 , , , , , , , , , , | Leave a comment

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 , , , , , , , , , | 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 , , , , , | Leave a comment

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

Posted in Arrays, Excel, Link to Python, NumPy and SciPy, UDFs, VBA | Tagged , , , , , , , , , | 2 Comments

Transferring and converting strings in Excel and Python

The load table for the 3D Frame spreadsheet has a column listing the global axis for each load as text (X, Y, or Z).  In the VBA version the table is converted to a variant array, and the axes are handled … Continue reading

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xlwSciPy 1.7

Following recent posts on xlwings 0.7.1, dictionaries, and optional arguments and xlwings – dataframes and statistics, I have added the associated functions and examples to the xlwSciPy spreadsheet, and also updated it to xlwings 0.71. The new spreadsheet can be … Continue reading

Posted in Excel, Link to Python, Maths, Newton, NumPy and SciPy, Python Pandas, UDFs, VBA | Tagged , , , , , , , , | 4 Comments

Numpy and Scipy for Excel

The Python Numpy and Scipy libraries contain a huge number of maths and science related functions.  Most of these are not directly available from Excel, but using the free ExcelPython package it is fairly easy to make the link, vastly increasing … Continue reading

Posted in Excel, Link to Python, Maths, NumPy and SciPy, UDFs, VBA | Tagged , , , , , , | 11 Comments