# Eigenvectors for a large symbolic matrix

I'm trying to compute the eigenvectors for a 42x42 symbolic matrix (with one variable) in Mathematica. I get the following error:

Eigenvectors::eivec0: Unable to find all eigenvectors. >>

You seem to mix exact integers with floating point. Try: Eigensystem[mat/. j-> 1.0*j ] ; I got a result in a few seconds using version 9.0. You could also have mentioned that your matrix is degree 1 in 'j' on the diagonal, and is all zero except at two above and below the diagonal. – Wouter Mar 30 '14 at 17:46