Date: Thu, 2 Aug 2001 15:55:24 -0600 (MDT) From: Travis Oliphant <oliphant@ee.byu.edu> To: <scipy-dev@scipy.org> Subject: [SciPy-dev] Spline module

I'm not necessarily opposed to a separate splines module. But, splines do get used in a number of different ways --- and the algorithms used in each domain do tend to differ.

Perhaps your spline code would be better in a finite-element package, rather than a spline module.

Love to have more help with scipy...

I don't mind f77 code (but then again I haven't dealt with the Windows headaches as much as eric :-) ).

-Travis

Well, I base my code on some general B-spline code (written in F77) from the SLATEC library in Netlib. I only use less than a half dozen functions from the library, but it does include: BINT4 - interpolates with splines of order 4 BINTK - interpolates with splines of order k BSQAD - integrates the B-representation on subintervals PPQAD - integrates the PP-representation BFQAD - integrates the product of a function F and any spline derivative in the B-representation PFQAD - integrates the product of a function F and any spline derivative in the PP-representation BVALU - evaluates the B-representation or a derivative PPVAL - evaluates the PP-representation or a derivative INTRV - gets the largest index of the knot to the left of x BSPPP - converts from B- to PP-representation BSPVD - computes nonzero basis functions and derivatives at x BSPDR - sets up difference array for BSPEV BSPEV - evaluates the B-representation and derivatives BSPVN - called by BSPEV, BSPVD, BSPPP and BINTK for function and derivative evaluations where PP-representation is piecewise polynomial representation, and B-representation is B-spline representation. These are the basic functions the spline toolbox are based off of. From BSPVD one can get the tensor product B-spline form, which is what I do. There are some other routines in Carl de Boor, A Practical Guide to Splines, Applied Mathematics Series 27, Springer-Verlag, New York, 1978. for solving ODEs through co-location. The way I see things is that we can create a base spline module that includes the above functions (save BINT4 and BINTK) and have separate modules for: interpolation, solving ODEs through co-location, and my FEM code (possibly). Thoughts ? Cheers, Tim.