Finding the characteristic polynomial takes seconds in mathematica. Its evaluating the discriminant of that polynomial that takes so long.
A typical entry in the 21x21 looks like this 1/2 h (61 h k1 - 159 h k2 - 14 g Hz uB). I forgot the particle is spin 10 so the hamiltonian is 21x21, not...
I'm doing a calculation which finds the characteristic polynomial of a matrix, HH, with rather complex entries and then determines the discriminant of that polynomial. For smaller matrices up to around 7x7 it finishes evaluating the Discriminant command within a few hours, but at a 10x10, which...