I mentioned the ADSR as an example for how to save an interpolation. An ADSR is just four numbers specifying the state: "adsr 10 100 0.9 200". However those four values are used to interpolate another value: the volume of a signal for example - this is enveloped interpolation.
ok, it's just a question of word. for me an adsr is not interpolation because time is part of the adsr, but not for (my vision of ) the interpolation.
my vision of interpolation is more or less something like this :
http://cnmat.cnmat.berkeley.edu/~ali/documents/intuition.pdf
using [line] for interpolation is far away of what I nead for my specific use...
cyrille