On Sun, Aug 18, 2013 at 4:02 PM, Júlio Hoffimann <julio.hoffimann@gmail.com> wrote:

I've run into an eigenvalue problem where I need to compute the roots of a cubic polynomial.

If you're trying to solve the characteristic equation det(A-\lambda I) = 0 by hand, it's the wrong path. Try using an appropriate library for solving eigenproblems.

I'm aware that some lin-alg libraries, such as e.g. Eigen, includes eigenvalue solvers that might suit my needs. It would, however, be an advantage for me to avoid introducing any additional dependencies just to solve this "tiny" problem. Boost math already includes several math functions for root finding, so I was surprised over the lack of functions to solve lower order polynomials.

Fredrik