type t

val make :
  ?guess:('a, 'b) Matrix.t ->
  ?n_states:int ->
  ?n_iter:int ->
  ?threshold:float ->
  'a Vector.t ->
  (('a, 'b) Matrix.t -> ('a, 'b) Matrix.t) ->
  ('a, 'b) Matrix.t * 'b Vector.t

(** Performs a Davidson diagonalization. Example:

let eigenvectors, eigenvalues =
  Davidson.make diagonal mat_prod

- [diagonal] contains the diagonal of the matrix to diagonalize
- [mat_prod] is a function performing a matrix multiplication of the matrix to
  diagonalize with the matrix containing the current set of vectors
*)