qiskit.aqua.operators.legacy.WeightedPauliOperator

class WeightedPauliOperator(paulis, basis=None, z2_symmetries=None, atol=1e-12, name=None)

Weighted Pauli Operator

パラメータ

• paulis (List[List[Union[complex, Pauli]]]) – the list of weighted Paulis, where a weighted pauli is composed of a length-2 list and the first item is the weight and the second item is the Pauli object.

• basis (Optional[List[Tuple[object, List[int]]]]) – the grouping basis, each element is a tuple composed of the basis and the indices to paulis which belong to that group. e.g., if tpb basis is used, the object will be a pauli. By default, the group is equal to non-grouping, each pauli is its own basis.

• z2_symmetries (Optional[Z2Symmetries]) – recording the z2 symmetries info

• atol (float) – the threshold used in truncating paulis

• name (Optional[str]) – the name of operator.

__init__(paulis, basis=None, z2_symmetries=None, atol=1e-12, name=None)

パラメータ

• paulis (List[List[Union[complex, Pauli]]]) – the list of weighted Paulis, where a weighted pauli is composed of a length-2 list and the first item is the weight and the second item is the Pauli object.

• basis (Optional[List[Tuple[object, List[int]]]]) – the grouping basis, each element is a tuple composed of the basis and the indices to paulis which belong to that group. e.g., if tpb basis is used, the object will be a pauli. By default, the group is equal to non-grouping, each pauli is its own basis.

• z2_symmetries (Optional[Z2Symmetries]) – recording the z2 symmetries info

• atol (float) – the threshold used in truncating paulis

• name (Optional[str]) – the name of operator.

Methods

__init__(paulis[, basis, z2_symmetries, …])	type paulis List[List[Union[complex, Pauli]]]
add(other[, copy])	Perform self + other.
anticommute_with(other)	Anti commutes with
chop([threshold, copy])	Eliminate the real and imagine part of weight in each pauli by threshold.
commute_with(other)	Commutes with
construct_evaluation_circuit(wave_function, …)	Construct the circuits for evaluation, which calculating the expectation <psi|H|psi>.
copy()	Get a copy of self
evaluate_with_result(result, statevector_mode)	This method can be only used with the circuits generated by the construct_evaluation_circuit() method with the same circuit_name_prefix name since the circuit names are tied to some meanings.
evaluate_with_statevector(quantum_state)	param quantum_state a quantum state.
evaluation_instruction(statevector_mode[, …])	param statevector_mode will it be run on statevector simulator or not
evolve([state_in, evo_time, …])	Carry out the eoh evolution for the operator under supplied specifications.
evolve_instruction([evo_time, …])	Carry out the eoh evolution for the operator under supplied specifications.
from_dict(dictionary[, before_04])	Load paulis from a dictionary to construct an Operator.
from_file(file_name[, before_04])	Load paulis in a file to construct an Operator.
from_list(paulis[, weights, name])	Create a WeightedPauliOperator via a pair of list.
is_empty()	Check Operator is empty or not.
multiply(other)	Perform self * other, and the phases are tracked.
print_details()	Print out the operator in details.
reorder_paulis()	Reorder the paulis based on the basis and return the reordered paulis.
rounding(decimals[, copy])	Rounding the weight.
simplify([copy])	Merge the paulis whose bases are identical and the pauli with zero coefficient would be removed.
sub(other[, copy])	Perform self - other.
to_dict()	Save operator to a dict in pauli representation.
to_file(file_name)	Save operator to a file in pauli representation.
to_opflow([reverse_endianness])	to op flow

Attributes

atol	get atol
basis	returns basis
name	returns name
num_qubits	Number of qubits required for the operator.
paulis	get paulis
z2_symmetries	returns z2 symmetries

add(other, copy=False)

Perform self + other.

パラメータ

• other (WeightedPauliOperator) – to-be-combined operator

• copy (bool) – working on a copy or self, if False, the results are written back to self.

戻り値

operator

戻り値の型

WeightedPauliOperator

anticommute_with(other)

Anti commutes with

property atol

get atol

property basis

returns basis

chop(threshold=None, copy=False)

Eliminate the real and imagine part of weight in each pauli by threshold. If pauli’s weight is less then threshold in both real and imaginary parts, the pauli is removed.

注釈

If weight is real-only, the imaginary part is skipped.

パラメータ

• threshold (float) – the threshold is used to remove the paulis

• copy (bool) – chop on a copy or self

戻り値

if copy is True, the original operator is unchanged; otherwise,

the operator is mutated.

戻り値の型

WeightedPauliOperator

commute_with(other)

Commutes with

construct_evaluation_circuit(wave_function, statevector_mode, qr=None, cr=None, use_simulator_snapshot_mode=False, circuit_name_prefix='')

Construct the circuits for evaluation, which calculating the expectation <psi|H|psi>.

At statevector mode: to simplify the computation, we do not build the whole circuit for <psi|H|psi>, instead of that we construct an individual circuit <psi|, and a bundle circuit for H|psi>

パラメータ

• wave_function (QuantumCircuit) – the quantum circuit.

• statevector_mode (bool) – indicate which type of simulator are going to use.

• qr (QuantumRegister, optional) – the quantum register associated with the input_circuit

• cr (ClassicalRegister, optional) – the classical register associated with the input_circuit

• use_simulator_snapshot_mode (bool, optional) – if aer_provider is used, we can do faster evaluation for pauli mode on statevector simulation

• circuit_name_prefix (str, optional) – a prefix of circuit name

戻り値

a list of quantum circuits and each circuit with a unique name:

circuit_name_prefix + Pauli string

戻り値の型

list[QuantumCircuit]

例外

• AquaError – if Operator is empty

• AquaError – if quantum register is not provided explicitly and cannot find quantum register with q as the name

• AquaError – The provided qr is not in the wave_function

copy()

Get a copy of self

evaluate_with_result(result, statevector_mode, use_simulator_snapshot_mode=False, circuit_name_prefix='')

This method can be only used with the circuits generated by the construct_evaluation_circuit() method with the same circuit_name_prefix name since the circuit names are tied to some meanings.

Calculate the evaluated value with the measurement results.

パラメータ

• result (qiskit.Result) – the result from the backend.

• statevector_mode (bool) – indicate which type of simulator are used.

• use_simulator_snapshot_mode (bool) – if aer_provider is used, we can do faster evaluation for pauli mode on statevector simulation

• circuit_name_prefix (str) – a prefix of circuit name

戻り値

the mean value float: the standard deviation

戻り値の型

float

例外

AquaError – if Operator is empty

evaluate_with_statevector(quantum_state)

パラメータ

quantum_state (numpy.ndarray) – a quantum state.

戻り値

the mean value float: the standard deviation

戻り値の型

float

例外

AquaError – if Operator is empty

evaluation_instruction(statevector_mode, use_simulator_snapshot_mode=False)

パラメータ

• statevector_mode (bool) – will it be run on statevector simulator or not

• use_simulator_snapshot_mode (bool) – will it use qiskit aer simulator operator mode

戻り値

Pauli-instruction pair.

戻り値の型

dict

例外

• AquaError – if Operator is empty

• MissingOptionalLibraryError – qiskit-aer not installed

evolve(state_in=None, evo_time=0, num_time_slices=1, quantum_registers=None, expansion_mode='trotter', expansion_order=1)

Carry out the eoh evolution for the operator under supplied specifications.

パラメータ

• state_in (QuantumCircuit) – a circuit describes the input state

• evo_time (Union(complex, float, Parameter, ParameterExpression)) – The evolution time

• num_time_slices (int) – The number of time slices for the expansion

• quantum_registers (QuantumRegister) – The QuantumRegister to build the QuantumCircuit off of

• expansion_mode (str) – The mode under which the expansion is to be done. Currently support 『trotter』, which follows the expansion as discussed in http://science.sciencemag.org/content/273/5278/1073, and 『suzuki』, which corresponds to the discussion in https://arxiv.org/pdf/quant-ph/0508139.pdf

• expansion_order (int) – The order for suzuki expansion

戻り値

The constructed circuit.

戻り値の型

QuantumCircuit

例外

• AquaError – quantum_registers must be in the provided state_in circuit

• AquaError – if operator is empty

evolve_instruction(evo_time=0, num_time_slices=1, expansion_mode='trotter', expansion_order=1)

Carry out the eoh evolution for the operator under supplied specifications.

パラメータ

• evo_time (Union(complex, float, Parameter, ParameterExpression)) – The evolution time

• num_time_slices (int) – The number of time slices for the expansion

• expansion_mode (str) – The mode under which the expansion is to be done. Currently support 『trotter』, which follows the expansion as discussed in http://science.sciencemag.org/content/273/5278/1073, and 『suzuki』, which corresponds to the discussion in https://arxiv.org/pdf/quant-ph/0508139.pdf

• expansion_order (int) – The order for suzuki expansion

戻り値

The constructed QuantumCircuit.

戻り値の型

QuantumCircuit

例外

• ValueError – Number of time slices should be a non-negative integer

• NotImplementedError – expansion mode not supported

• AquaError – if operator is empty

classmethod from_dict(dictionary, before_04=False)

Load paulis from a dictionary to construct an Operator. The dictionary must comprise the key 『paulis』 having a value which is an array of pauli dicts. Each dict in this array must be represented by label and coeff (real and imag) such as in the following example:

{'paulis':
    [
        {'label': 'IIII',
         'coeff': {'real': -0.33562957575267038, 'imag': 0.0}},
        {'label': 'ZIII',
         'coeff': {'real': 0.28220597164664896, 'imag': 0.0}},
         ...
    ]
 }

パラメータ

• dictionary (dict) – dictionary, which contains a list of Paulis and coefficients.

• before_04 (bool) – support the format before Aqua 0.4.

戻り値

the operator created from the input dictionary.

戻り値の型

WeightedPauliOperator

例外

AquaError – Invalid dictionary

classmethod from_file(file_name, before_04=False)

Load paulis in a file to construct an Operator.

パラメータ

• file_name (str) – path to the file, which contains a list of Paulis and coefficients.

• before_04 (bool) – support the format before Aqua 0.4.

戻り値

the loaded operator.

戻り値の型

WeightedPauliOperator

classmethod from_list(paulis, weights=None, name=None)

Create a WeightedPauliOperator via a pair of list.

パラメータ

• paulis (list[Pauli]) – the list of Paulis

• weights (list[complex], optional) – the list of weights, if it is None, all weights are 1.

• name (str, optional) – name of the operator.

戻り値

operator

戻り値の型

WeightedPauliOperator

例外

ValueError – The length of weights and paulis must be the same

is_empty()

Check Operator is empty or not.

戻り値

True if empty, False otherwise

戻り値の型

bool

multiply(other)

Perform self * other, and the phases are tracked.

パラメータ

other (WeightedPauliOperator) – an operator

戻り値

the multiplied operator

戻り値の型

WeightedPauliOperator

property name

returns name

property num_qubits

Number of qubits required for the operator.

戻り値

number of qubits

戻り値の型

int

property paulis

get paulis

print_details()

Print out the operator in details.

戻り値

a formatted string describes the operator.

戻り値の型

str

reorder_paulis()

Reorder the paulis based on the basis and return the reordered paulis.

戻り値の型

List[List[Union[complex, Pauli]]]

戻り値

the ordered paulis based on the basis.

rounding(decimals, copy=False)

Rounding the weight.

パラメータ

• decimals (int) – rounding the weight to the decimals.

• copy (bool) – chop on a copy or self

戻り値

operator

戻り値の型

WeightedPauliOperator

simplify(copy=False)

Merge the paulis whose bases are identical and the pauli with zero coefficient would be removed.

注釈

This behavior of this method is slightly changed, it will remove the paulis whose weights are zero.

パラメータ

copy (bool) – simplify on a copy or self

戻り値

the simplified operator

戻り値の型

WeightedPauliOperator

sub(other, copy=False)

Perform self - other.

パラメータ

• other (WeightedPauliOperator) – to-be-combined operator

• copy (bool) – working on a copy or self, if False, the results are written back to self.

戻り値

operator

戻り値の型

WeightedPauliOperator

to_dict()

Save operator to a dict in pauli representation.

戻り値

a dictionary contains an operator with pauli representation.

戻り値の型

dict

to_file(file_name)

Save operator to a file in pauli representation.

パラメータ

file_name (str) – path to the file

to_opflow(reverse_endianness=False)

to op flow

property z2_symmetries

returns z2 symmetries