I think it's a very non-trivial task to "just" copy and paste a three-decade-old program that has tens of thousands of lines of dependencies, making sure to rem

I think it's a very non-trivial task to "just" copy and paste a three-decade-old program that has tens of thousands of lines of dependencies, making sure to remember to add conjugates as necessary. :) Eigenvalues and eigenvectors are notoriously difficult programs to get right for general matrices with no known properties a priori.