Tag Archives: curve fitting

More circle fitting options with Scipy

Posted on 17/03/2018 by dougaj4

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 , , , , , , , | Leave a comment

Excel to Alglib via xlwings

Posted on 11/08/2017 by dougaj4

The Alglib library provides many valuable numerical analysis routines, but the VBA version is no longer actively maintained.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 , , , , , , , , , | 12 Comments

ExcelPython2, Alglib and Spline-Matrix update

Posted on 12/09/2014 by dougaj4

The ExcelPython add-in, offering easy access to Python code from Excel VBA, has had a major update to Release 2.  The new version provides new features and simpler installation, but has some incompatibilities with code written for the previous  version, so the … Continue reading →

Posted in AlgLib, Excel, Link to Python, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , | 4 Comments

Daily Download 22: Splines and Curves

Posted on 08/10/2012 by dougaj4

Since it was first published in 2009 my CSpline function has been the most popular download from this site.  CSpline (and various associated functions) is used to fit a series of cubic curves through specified points, allowing interpolation along a smooth … Continue reading →

Posted in AlgLib, Beam Bending, Charts, Charts, Coordinate Geometry, Excel, Newton, Numerical integration, UDFs, VBA | Tagged , , , , , , , , | 7 Comments

Spline Interpolation Alternatives

Posted on 04/09/2011 by dougaj4

A recent post at Jon Peltier’s Blog looks at an “on-sheet” method of performing linear interpolation on a set of tabular data, and the following comments include a number of alternative ways of carrying out the same process, and also some … Continue reading →

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , | 7 Comments