INTERP does (n-1)th order interpolation, where `n' must be an even number; thus only odd orders greater than zero are handled. For example, n=2 gives 1st order (i.e. linear) interpolation; n=4 gives 3rd order (i.e. quartic) interpolation. (INTERP cannot supply quadratic interpolation, since this would require n=3 and odd values of `n' are not allowed.)
The data must have monotonically increasing X values.
Note that spline interpolation can also be executed, using the CDRAW command.
DIPSO --- A friendly spectrum analysis program