Interpolation with Rounded Ramp Functions
A new interpolation function is introduced.
 It has infinitely many continuous derivatives 
and is a composition of ramp functions with smoothed bends
called Rounded Ramp Functions.  How the interpolation 
function can be extended to more than one variable is
shown.  An efficient Fortran program is given by 
which the interpolation function can be obtained for a given point set.
CACM August, 1974
Lagerlof, R. O. E.
