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# Tag Archives: Numpy

## More circle fitting options with Scipy

A comment on the first post on this topic found that the method used did not work well for short arcs of large radius circles. An example of the problem can be seen in the screen shots below: The function … Continue reading

Posted in Coordinate Geometry, Curve fitting, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings
Tagged curve fitting, Excel, least squares, Numpy, ODR, Python, SciPy, VBA
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## More Python rotation functions

The code described in the previous post includes a Python function that rotates 3D coordinates by an angle defined with two vectors, using Rodrigue’s Rotation. I have now added this function to the IP2_py spreadsheet, where it is used in the … Continue reading

Posted in Coordinate Geometry, Drawing, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings
Tagged Excel, fit 3D circle, Numpy, Python, RPView, UDF, VBA, xlwings, xl_RPView
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## Fitting 3D circles to scattered points

Following a comment at update-to-glob_to_loc3-and-loc_to_glob3-functions, I have modified the Python code at the linked site, so it can be run from Excel, via xlwings. The spreadsheet described below, and the associated Python code, can be download from: 3DCirc.zip The original … Continue reading

Posted in Coordinate Geometry, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings
Tagged 3DCirc, Excel, fit 3D circle, Numpy, Python, UDF, VBA, xlwings
5 Comments

## 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