Tag Archives: Interpolation

VBA procedures for the Numerical Analysis of Tabular Functions

Posted on March 12, 2022 by dougaj4

Long time on-line friend Alfred Vachris has recently been converting Fortran code developed through his working career into VBA: I had the opportunity to work at Grumman while going to Graduate School and they gave me a part-time job as … Continue reading →

Posted in Coordinate Geometry, Curve fitting, Excel, Fortran, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 1 Comment

Daily Download 22: Splines and Curves

Posted on October 8, 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 September 4, 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

Interpolation Update

Posted on December 7, 2010 by dougaj4

The interpolation functions in IP2.xls have been given an overhaul: The linear and quadratic interpolations routines have been modified to accept negative values. All the routines have been modified to convert the table range to an array, rather than using a … Continue reading →

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , | 4 Comments

Another update to IP.xls

Posted on April 7, 2009 by dougaj4

Following some suggestions from Mike Seymour I have modified my polyline intersection function, and added a new version. The changes are: The data ranges for the new function, IP4(), are entered as four separate ranges, so the X and Y … Continue reading →

Posted in Excel, Maths, UDFs, VBA | Tagged , , , , | 1 Comment