Dear Team who work on GSL, First of all I would like to thank you for this project, which I use in my work in my phd thesis. I work in Ecole Polytechnique in France on the topic of tomography. Me and my supervisor work in particular work on tomography in 3d (in 3 dimensions, thought it is usually done in 2 dimensions) and on implementation of new algorithms. http://www.cmap.polytechnique.fr/~fedor.goncharov/
To code them I use a bit of GSL and I'm happy that native C in linux distributions have this library installed. My question, or suggestion, would be implementation in GSL of interpolations in 3D (trlinear, for example). It is easy to realize interpolation in 3D by hand having already 2D interpolations from GSL, but having these commands inside the library will look more natural. Especially because all these numerical procedures are often used in numerical analysis in dimensions 1, 2, 3. p.s. Sorry that I don't propose my help, since I don't have much time already working on thesis. All best, Fedor Goncharov