B-Spline Fortran 4.0


My bspline-fortran multidimensional interpolation library is now at version 4.0. The documentation can be found here. Since I first mentioned it here, I’ve made many updates to this library, including:

  • Added object-oriented wrappers to the core routines. The user now has the choice to use the older subroutine interface or the new object-oriented interface.
  • Added a set of 1D routines (suggested by a user on GitHub). The library now works for 1D-6D data sets.
  • Everything is now thread-safe for your multithreaded pleasure.

The new object-oriented interface makes it pretty easy to use from modern Fortran. The classes have only three methods (initialize, evaluate, and destroy). For example, a 3D case would look like this:

type(bspline_3d) :: s
call s%initialize(x,y,z,fcn,kx,ky,kz,iflag)
call s%evaluate(xval,yval,zval,idx,idy,idz,f,iflag)
call s%destroy() 

The core routines of bspline-fortran were written in the early 1980s. Good Fortran code can live on for decades after it is written. While this is great, it also means that there is a lot of old Fortran code out there that is written in a coding style that no modern programmer should accept. This can be OK for well documented library routines that the user never needs to change (see, for example SPICE or LAPACK). However, refactoring old code using modern concepts can provide many advantages, as is demonstrated in this case.

See also

  1. DBSPLIN and DTENSBS from the NIST Core Math Library.
  2. Carl de Boor, A Practical Guide to Splines, Springer-Verlag, New York, 1978.
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One comment on “B-Spline Fortran 4.0
  1. Stefano says:

    Great work!

    Great Jacob!

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