I'm looking for a definition of a functional
f which works correctly with varying arguments
t while it will be nested.
For example, I've the following code
f[g__[t__]] := g[t] + g[t - s]
For an input function
in[t] I'll get
So far so good. But I want to nest the functional like
f[f[in[t]] and I'm expecting
as result. But what I get with the above definition is
-s + 2 in[t] + 2 in[-s + t]. My application is a cascaded FIR digital filter. The output of the first FIR is the input of the next one and so on.