inv_coeff — build a polynomial matrix from its coefficients
[P]=inv_coeff(C,[,d,[name])
big matrix of the coefficients
Polynomial matrix degree. optional parameter with default value d=-1+size(C,'c')/size(C,'r')
string giving the polynomial variable name (default value 'x').
P=inv_coeff(Mp,k), when k is compatible with Mp
size, returns a polynomial matrix of degree k. C=[C0,C1,...,Ck] and
P= C0 + C1*x +... +Ck*x^k.