This module allows to create and manage orthogonal polynomials.
Features
--------
For each polynomial "x", the following functions are
available :
* x_eval : Evaluate Chebyshev polynomial
* x_norm : Compute Chebyshev L2 norm
* x_pdf : Chebyshev PDF
* x_poly : Create Chebyshev polynomial
* x_variance : Variance of Chebyshev polynomials
* x_weight : Chebyshev weight function
with :
* x="chebyshev" : Chebyshev Polynomials
* x="hermite" : Hermite Polynomials
* x="laguerre" : Laguerre Polynomials
* x="legendre" : Legendre Polynomials
