Here is the beginning of a package http://nbviewer.ipython.org/gist/lstagner/04a05b120e0be7de9915
-Luke On Wednesday, May 13, 2015 at 1:03:34 AM UTC-7, René Donner wrote: > > > Thin plate splines are just a special case of Polyharmonic Splines. > Would there be interest of expanding this script into a package? > > Yes please, that would be great to have! > > > > > -Luke > > > > On Wednesday, May 13, 2015 at 12:26:12 AM UTC-7, Jan Kybic wrote: > > I have a set of irregularly gridded data (x,y,z) and I am trying to > create an interpolating surface using Thin Plate Splines. I couldn't find > any existing Julia routines so I thought I'd just do it my self. Here is my > implementation. As you can see its wrong. I been staring at it for a while > now and I am beginning to think I must be hitting some sort of bug or quirk > of the language. It either that or I did something wrong. If I get this to > work I was thinking about incorporating it into one of the existing > interpolation packages. > > > > Can anyone figure out why this is not working? > > > > > > Hello. I have never seen the formulas you are using to find 'a' and 'b' > and I do not have the time to check. Provided they are correct, I would > suspect numerical problems - it is often not a good idea to calculate a > matrix inverse explicitely and the TPS matrix is ill-conditioned for even a > moderate number of points. I am attaching my Matlab implementation - you > see that I am solving the linear system by SVD, which is more stable. It > should be trivial to translate to Julia. Hope this helps. > > > > Jan > >
