# Arnoldi

Inheritance Diagram

Methods

 `Arnoldi.__init__`(H, psi0, options) `Arnoldi.iadd_prefactor_other`(w, alpha, v) `Arnoldi.iscale_prefactor`(w, scale) Find the ground state of H.
class tenpy.linalg.krylov_based.Arnoldi(H, psi0, options)[source]

Bases: `KrylovBased`

Arnoldi method for diagonalizing square, non-hermitian/symmetric matrices.

Generalization of `LanczosGroundState`, allowing general, square matrices.

Options

config Arnoldi
option summary

cutoff (from KrylovBased) in KrylovBased

Cutoff to abort if the norm of the new krylov vector is too small. [...]

E_shift (from KrylovBased) in KrylovBased

Shift the energy (=eigenvalues) by that amount *during* the Lanczos run by [...]

min_gap (from KrylovBased) in KrylovBased

Lower cutoff for the gap estimate used in the P_tol criterion.

N_max (from KrylovBased) in KrylovBased

Maximum number of steps to perform.

N_min (from KrylovBased) in KrylovBased

Minimum number of steps to perform.

num_ev

Number of eigenvectors to look for/return in `run`.

P_tol (from KrylovBased) in KrylovBased

Tolerance for the error estimate from the Ritz Residual, [...]

which

Determines which (extremal) eigenvalues to look for, name [...]

option which: `'LM' | 'LR' | 'SR'`

Determines which (extremal) eigenvalues to look for, name largest magnitude (in absolute value, `'LM'`), or largest or smallest real part (`'LR'` and `'SR'`, respectively).

option num_ev: int

Number of eigenvectors to look for/return in run.

run()[source]

Find the ground state of H.

Returns: