Hi Miles,

Can I use `davidson`

function to obtain the low-lying eigenvectors corresponding to a ITensor, and a given initial guess, similar to `diagHermitian`

function? Is it possible to do?

Titas

**EDIT**

Motivated from the `localmpo`

class, I have created a wrapper class for ITensor objects (in the matrix form, which is also required for `diagHermitian`

), containing a `const&`

of the actual object, say `A`

. The wrapper class have three member functions -- (1) `product(psi, phi)`

which computes `A*psi`

and store it on `phi`

; (2) `diag()`

which returns diagonal tensor of `A`

, can be easily defined using `delta()`

; (3) `size()`

which returns total dimension of all unprimed indices.

I hope, I am doing it correctly.