There is a Matlab-based package called Chebfun that (among other things) computes polynomial approximations of functions. See here: http://www2.maths.ox.ac.uk/chebfun/. I don't know anything about ...
A question recently came up regarding Parks-McClellan and some of the comments point out that the wikipedia article on Parks-McClellan states, ...the Parks-McClellan algorithm is a variation of ...
We can easily design interpolation filters that obey certain frequency-domain constraints using the Parks-McClellan algorithm. However, it's not immediately clear how to enforce time-domain ...