Reciprocal polynomial ($p^{\ast }(X)=X^{\mathrm{deg}p}p(X^{-1})$)

The reciprocal polynomial reverses the coefficients of a polynomial with nonzero constant term. For a binary cyclic code with generator $g$ and canonical check polynomial $h$, the reciprocal $h^{\ast }$ generates the dual of a cyclic code.

// Target: algebra.bigb