Fix compilation of Tridiagonalization_diagonal example. After changeset 63806965d637, matrixT() is a real matrix even if the matrix which is decomposed is complex.
Fix compilation of Tridiagonalization_diagonal example.
After changeset 63806965d637, matrixT() is a real matrix even if the matrix
which is decomposed is complex.

madlib/eigen,madlib/eigen,madlib/eigen,madlib/eigen