Source code for netket.operator._abstract_operator
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import abc
from netket.utils.types import DType
from netket.hilbert import AbstractHilbert
from ._abstract_observable import AbstractObservable
[docs]
class AbstractOperator(AbstractObservable):
"""Abstract class for quantum Operators.
An operator is a general object that defines a linear transformation
on vectors of the Hilbert space and their expectation value can
be comptued starting from a variational state using the method
`expect` or `expect_and_grad` of the variational states.
If the object is not a linear operator but some more general
function, it should inherit from {class}`~netket.operator.AbstractObservable`
instead.
Operators over discrete hilbert spaces that can be converted
to a dense representation should instead inherit from
{class}`~netket.operator.DiscreteOperator`, while operators
over that only work over continuous hilbert spaces should
inherit from {class}`~netket.operator.ContinuousOperator`.
This class determines the basic methods that an operator
must implement to work correctly with NetKet.
"""
def __init__(self, hilbert: AbstractHilbert):
super().__init__(hilbert)
@property
def is_hermitian(self) -> bool:
"""Returns true if this operator is hermitian."""
return False
@property
def H(self) -> "AbstractOperator":
"""Returns the Conjugate-Transposed operator"""
if self.is_hermitian:
return self
from ._lazy import Adjoint
return Adjoint(self)
@property
def T(self) -> "AbstractOperator":
"""Returns the transposed operator"""
return self.transpose()
@property
@abc.abstractmethod
def dtype(self) -> DType:
"""The dtype of the operator's matrix elements ⟨σ|Ô|σ'⟩."""
[docs]
def collect(self) -> "AbstractOperator":
"""
Returns a guaranteed concrete instance of an operator.
As some operations on operators return lazy wrappers (such as transpose,
hermitian conjugate...), this is used to obtain a guaranteed non-lazy
operator.
"""
return self
[docs]
def transpose(self, *, concrete=False) -> "AbstractOperator":
"""Returns the transpose of this operator.
Args:
concrete: if True returns a concrete operator and not a lazy wrapper
Returns:
if concrete is not True, self or a lazy wrapper; the
transposed operator otherwise
"""
if not concrete:
from ._lazy import Transpose
return Transpose(self)
else:
raise NotImplementedError
[docs]
def conjugate(self, *, concrete=False) -> "AbstractOperator":
"""Returns the complex-conjugate of this operator.
Args:
concrete: if True returns a concrete operator and not a lazy wrapper
Returns:
if concrete is not True, self or a lazy wrapper; the
complex-conjugated operator otherwise
"""
raise NotImplementedError
[docs]
def conj(self, *, concrete=False) -> "AbstractOperator":
return self.conjugate(concrete=False)
def __repr__(self):
return f"{type(self).__name__}(hilbert={self.hilbert}, dtype={self.dtype})"