DummyTwoSiteH

full name: tenpy.algorithms.mps_common.DummyTwoSiteH
parent module: tenpy.algorithms.mps_common
type: class

Inheritance Diagram

Methods

`DummyTwoSiteH.__init__`(args, *kwargs)
`DummyTwoSiteH.adjoint`()	Return the hermitian conjugate of self
`DummyTwoSiteH.combine_theta`(theta)	Combine the legs of theta, such that it fits to how we combined the legs of self.
`DummyTwoSiteH.matvec`(vec)	Calculate the action of the operator on a vector vec.
`DummyTwoSiteH.to_matrix`()	Contract self to a matrix.
`DummyTwoSiteH.update_LP`(env, i[, U])	Equivalent to `env.get_LP(i, store=True)`; optimized for combine.
`DummyTwoSiteH.update_RP`(env, i[, VH])	Equivalent to `env.get_RP(i, store=True)`; optimized for combine.

Class Attributes and Properties

`DummyTwoSiteH.acts_on`
`DummyTwoSiteH.length`

class tenpy.algorithms.mps_common.DummyTwoSiteH(*args, **kwargs)[source]

Bases: EffectiveH

A dummy replacement for TwoSiteH() with similar methods but no actual MPO.

This allows to base the VariationalCompression on the Sweep class.

combine_theta(theta)[source]

Combine the legs of theta, such that it fits to how we combined the legs of self.

Parameters:: theta (Array) – Wave function to apply the effective Hamiltonian to, with uncombined legs.
Returns:: theta – Wave function with labels as given by self.acts_on.
Return type:: Array

adjoint()[source]

Return the hermitian conjugate of self

If self is hermitian, subclasses can choose to implement this to define the adjoint operator of self.

matvec(vec)[source]

Calculate the action of the operator on a vector vec.

Note that we don’t require vec to be one-dimensional. However, for square operators we require that the result of matvec has the same legs (in the same order) as vec such that they can be added. Note that this excludes a non-trivial qtotal for square operators.

to_matrix()[source]

Contract self to a matrix.

If self represents an operator with very small shape, e.g. because the MPS bond dimension is very small, an algorithm might choose to contract self to a single tensor.

Returns:: matrix – Contraction of the represented operator.
Return type:: Array

update_LP(env, i, U=None)[source]

Equivalent to env.get_LP(i, store=True); optimized for combine.

Parameters:

env (MPOEnvironment) – The same environment as given during class initialization.
i (int) – We update the part left of site i. Can optimize if i == i0 and combine is True.
U (None | Array) – The tensor on the left-most site self acts on, with combined legs after SVD. Only used if trying to optimize.

update_RP(env, i, VH=None)[source]

Equivalent to env.get_RP(i, store=True); optimized for combine.

Parameters:

env (MPOEnvironment) – The same environment as given during class initialization.
i (int) – We update the part right of site i. Can optimize if i == i0 + 2 - length and combine is True.
U (None | Array) – The tensor on the right-most site self acts on, with combined legs after SVD. Only used if trying to optimize.