[comp.sys.apollo] GPR Cubic Spline Algorithm

ferguson@BKNLVMS.BITNET (03/15/88)

Does anyone have the specification for the algorithm used in
GPR_$SPLINE_CUBIC_P (the parametric one)? I've got a program
called XYPLOT (it's in the ADUS lib) which uses GPR for the
screen, and then Imagen imPress for hardcopy (sorry, I don't
know Postscript, but I'm working on HPGL). Since Imagen doesn't
have a cubic spline built into hardware, I copied an algorithm
out of "Numerical Analysis", by Burden, Faires, and Reynolds.

Unfortunately, the curves don't always look the same. If anyone
could tell me where to find the GPR algorithm, I would sell you
my first born.

Thanks,

Scott Ferguson
Bucknell University
ferguson@bknlvms.bitnet