- the array of matrices associated with the eigenproblem
Notes
The polynomial eigenproblem is defined as P(l)*x=0, where l is
the eigenvalue, x is the eigenvector, and P(l) is defined as
P(l) = A_0 + l*A_1 + ... + l^d*A_d, with d=nmat-1 (the degree of P).
For non-monomial bases, this expression is different.