openfermion.ops.InteractionRDM

Class for storing 1- and 2-body reduced density matrices.

Inherits From: PolynomialTensor

openfermion.ops.InteractionRDM(
    one_body_tensor, two_body_tensor
)

one_body_tensor Expectation values .
two_body_tensor Expectation values .

one_body_tensor The expectation values .
two_body_tensor The expectation values .
constant The value of the constant term.
n_body_tensors

n_qubits

Methods

expectation

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expectation(
    operator
)

Return expectation value of an InteractionRDM with an operator.

Args
operator A QubitOperator or InteractionOperator.

Returns
float Expectation value

Raises
InteractionRDMError Invalid operator provided.

get_qubit_expectations

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get_qubit_expectations(
    qubit_operator
)

Return expectations of QubitOperator in new QubitOperator.

Args
qubit_operator QubitOperator instance to be evaluated on this InteractionRDM.

Returns
QubitOperator QubitOperator with coefficients corresponding to expectation values of those operators.

Raises
InteractionRDMError Observable not contained in 1-RDM or 2-RDM.

projected_n_body_tensors

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projected_n_body_tensors(
    selection, exact=False
)

Keep only selected elements.

Args
selection Union[int, Iterable[int]

If int, keeps terms with at most (exactly, if exact is True) that many unique indices. If iterable, keeps only terms containing (all of, if exact is True) the specified indices.

exact bool

Whether or not the selection is strict.

rotate_basis

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rotate_basis(
    rotation_matrix
)

Rotate the orbital basis of the PolynomialTensor.

Args
rotation_matrix A square numpy array or matrix having dimensions of n_qubits by n_qubits. Assumed to be real and invertible.

with_function_applied_elementwise

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with_function_applied_elementwise(
    func
)

__add__

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__add__(
    addend
)

__eq__

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__eq__(
    other
)

Return self==value.

__getitem__

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__getitem__(
    args
)

Look up matrix element.

Args
args Tuples indicating which coefficient to get. For instance, my_tensor[(6, 1), (8, 1), (2, 0)] returns my_tensor.n_body_tensors[1, 1, 0][6, 8, 2]

__iter__

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__iter__()

Iterate over non-zero elements of PolynomialTensor.

__mod__

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__mod__(
    other
)

__mul__

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__mul__(
    multiplier
)

__ne__

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__ne__(
    other
)

Return self!=value.

__neg__

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__neg__()

__radd__

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__radd__(
    addend
)

__rmul__

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__rmul__(
    multiplier
)

__rsub__

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__rsub__(
    subtrahend
)

__sub__

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__sub__(
    subtrahend
)

__truediv__

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__truediv__(
    dividend
)