Are you sure you pushed_back a few elements inside the vector? And I see no reason why having a std::vector inside a class would be a problem, makes no sense. There are a few requirements for the std::vector element type, IIRC, it must be default constructable, copy constructable and assignable...
Now I see that its better to use a numerical method, specially because I don't need a very accurate approximation for my specific application. Then I will give a try to that Jacobi method. Do you guys think this is one of the best choices for symmetrical 3x3 matrices?
Thanks.
Actually, I have to implement it myself in C++ code. Since there's a formula for the exact solution of a cubic equation I think its better to use it then. Numerical methods have problems finding all roots, don't they?
Uh I think using these methods is a waste for 3x3 matrices. After looking...
I know how to do this with pencil and paper, or in my mind perhaps ^^. But how to do it in programming? I don't know methods to compute a solution space (not only a single solution as most usual methods do like Gauss Seidel, Conugate Gradients, etc)..
I need to compute the 3 eigenvalues and 3 eigenvectors of a symmetric 3x3 matrix, namely a stress tensor, computationaly (in C++). More specific details http://en.wikipedia.org/wiki/Principal_stress#Principal_stresses_and_stress_invariants". Basically 2 questions:
1. I am running into trouble...