Tag Archives: Cubic spline

Daily Download 22: Splines and Curves

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 , , , , , , , , | 6 Comments

Alglib Spline Functions 1.32

Following a comment to AlgLib Spline Functions, the AL-Spline-Matrix spreadsheets have been updated, and may be downloaded from AL-Spline-Matrix03 for Excel 2003 and earlier and AL-Spline-Matrix07 for Excel 2007 and 2010.

Posted in AlgLib, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , , , | Leave a comment

Revision to CSpline2.xls

It was recently reported to me that the cubic spline spreadsheet CSpline2.xls (posted here) was crashing on loading in Excel 2003.  It seems that the problem was with the ChartSpline function, and that there are no problems if this function is … Continue reading

Posted in Drawing, Excel, Maths, UDFs, VBA | Tagged , , | 6 Comments

SplineBeam update

Previous SplineBeam post I have modified the SplineBeam spreadsheet to allow input of a single span (simply supported or with end constraints), and to optionally allow input of the position of intermediate nodes, rather than dividing each span into equal segment lengths.  This … Continue reading

Posted in Arrays, Beam Bending, Excel, Frame Analysis, Newton, UDFs, VBA | Tagged , , , , | 1 Comment

AlgLib Spline Functions

Following earlier posts on cubic splines I have collected the Alglib interpolation routines, and the necessary supporting routines, and written interface functions to allow most of the 1Dspline routines to be called from the spreadsheet.  Since there is a large measure … Continue reading

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , , , | 6 Comments

Cubic Hermitic and Cardinal Splines

In my previous post on splines I described a quick and dirty approach to adjusting a cubic spline to fit monotonic data, which did not meet with universal approval, so I have followed up Mike Woodhouse’s link: (http://en.wikipedia.org/wiki/Monotone_cubic_interpolation) which gives a … Continue reading

Posted in Charts, Excel, Maths, UDFs, VBA | Tagged , , , , , , | 8 Comments

Using Cubic Splines in Practice

I recently had an interesting query from Georg,  a geography student in Germany regarding the use of cubic splines to fit a smooth curve to experimental data.  The graph he sent me is shown below: The cubic spline has produced … Continue reading

Posted in Charts, Excel, Maths, Newton, UDFs | Tagged , | 9 Comments