TwoSiteH¶
full name: tenpy.algorithms.mps_common.TwoSiteH
parent module:
tenpy.algorithms.mps_common
type: class
Inheritance Diagram
Methods
|
Initialize self. |
Return the hermitian conjugate of self. |
|
Combine LP and RP with W to form LHeff and RHeff. |
|
|
Combine the legs of theta, such that it fits to how we combined the legs of self. |
|
Apply the effective Hamiltonian to theta. |
Contract self to a matrix. |
Class Attributes and Properties
-
class
tenpy.algorithms.mps_common.
TwoSiteH
(env, i0, combine=False, move_right=True)[source]¶ Bases:
tenpy.algorithms.mps_common.EffectiveH
Class defining the two-site effective Hamiltonian for Lanczos.
The effective two-site Hamiltonian looks like this:
| .--- ---. | | | | | | LP----W0--W1---RP | | | | | | .--- ---.
If combine is True, we define LHeff and RHeff, which are the contractions of LP with W0, and RP with W1, respectively.
- Parameters
env (
MPOEnvironment
) – Environment for contraction<psi|H|psi>
.i0 (int) – Index of the active site if length=1, or of the left-most active site if length>1.
combine (bool) – Whether to combine legs into pipes. This combines the virtual and physical leg for the left site (when moving right) or right side (when moving left) into pipes. This reduces the overhead of calculating charge combinations in the contractions, but one
matvec()
is formally more expensive, \(O(2 d^3 \chi^3 D)\).move_right (bool) – Whether the the sweep is moving right or left for the next update.
-
combine
¶ Whether to combine legs into pipes. This combines the virtual and physical leg for the left site and right site into pipes. This reduces the overhead of calculating charge combinations in the contractions, but one
matvec()
is formally more expensive, \(O(2 d^3 \chi^3 D)\).- Type
-
acts_on
¶ Labels of the state on which self acts. NB: class attribute. Overwritten by normal attribute, if combine.
- Type
list of str
-
LHeff
¶ Left part of the effective Hamiltonian. Labels
'(vR*.p0)', 'wR', '(vR.p0*)'
for bra, MPO, ket.- Type
-
RHeff
¶ Right part of the effective Hamiltonian. Labels
'(p1*.vL)', 'wL', '(p1.vL*)'
for ket, MPO, bra.- Type
-
LP, W0, W1, RP
Tensors making up the network of self.
- Type
-
combine_Heff
()[source]¶ Combine LP and RP with W to form LHeff and RHeff.
Combine LP with W0 and RP with W1 to get the effective parts of the Hamiltonian with piped legs.