These two Smath documents go together. They highlight the two
Smath built-in "ainterp, cinterp" for appropriate application(s).
Akima [ainterp] is complimentary to SS. Mathcad 11 and earlier
did not have such a good cubic spline. Though Akima was proved
disatrous in some applications.

The "Model" data was design by the Mathsoft Collab group mostly
to warn user about under the hood of "cubic splines". In fact,
not knowing more about the given data set, the cubic spline is
the wrong approach ... the data set is by inspection not cubic.
That Akima does a good job here, is pure coincidence.

Jean

Spline Quadratic Holistic.sm (76 KiB) downloaded 69 time(s).

Spline Quadratic [Model].sm (66 KiB) downloaded 57 time(s).