Cubic spline interpolation

[bobshackleton]

I need to impose curve-smoothing interpolations on a large number of data series - basically eliminating a number of linearly changing data points on either side of a kink and impsoing a smooth curve. The Cardinal and Catmull-Rom spline methods in the ipolate procedure produces s-curves rather than simple curves. Has anyone written a procedure that uses a simple cubic spline to impose a simple curve in an interpolation?