Introduction - If you have any usage issues, please Google them yourself
Usage: yi=akimai(x,y,xi)
Given vectors x and y (of the same length)
and the array xi at which to interpolate,
fits piecewise cubic polynomials and returns
the interpolated values yi at xi.
Ref. : Hiroshi Akima, Journal of the ACM, Vol. 17, No. 4, October 1970,
pages 589-602.
Programmer: N. Shamsundar, University of Houston, 6/2002
Correction to lines 32-33, 9/2004, motivated by Gilford Ward,
to make routine work correctly for linear data.
Notes: Use only for precise data, as the fitted curve passes through the
given points exactly. This routine is useful for plotting a pleasingly
smooth curve through a few given points for purposes of plotting.