# Ordering of Eigenvectors [duplicate]

I am interested in computing the derivatives of the eigenvalues of a certain $$n\times n$$ Hermitian matrix $$M(t)$$. I know I can do this easily since I know the exact expression for $$\dot{M}$$, and the resulting matrix is time independent. The usual argument is that $$\dot{\lambda_i}(t)= \langle v_i(t),\dot{M}v_i(t) \rangle$$, where $$v_i(t)$$ are the instantaneous eigenvectors of M. The problem that I am running into is that when computing the $$v_i(t)$$ numerically, the Eigenvector command will rearrange the order of the eigenvectors as $$t$$ changes (most likely because two eigenvalues approach one another in value and cross). My idea would be to try to order the eigenvectors by minimizing their distance to a reference vector. Does anyone know if it's possible to implement this?