qiskit.opflow.primitive_ops.PauliSumOp¶

class PauliSumOp(primitive, coeff=1.0, grouping_type='None')[source]¶

Class for Operators backend by Terra’s SparsePauliOp class.

Parameters

primitive (SparsePauliOp) – The SparsePauliOp which defines the behavior of the underlying function.
coeff (Union[complex, ParameterExpression]) – A coefficient multiplying the primitive.
grouping_type (str) – The type of grouping. If None, the operator is not grouped.

Raises

TypeError – invalid parameters.

__init__(primitive, coeff=1.0, grouping_type='None')[source]¶

Parameters

primitive (SparsePauliOp) – The SparsePauliOp which defines the behavior of the underlying function.
coeff (Union[complex, ParameterExpression]) – A coefficient multiplying the primitive.
grouping_type (str) – The type of grouping. If None, the operator is not grouped.

Raises

TypeError – invalid parameters.

Methods

`__init__`(primitive[, coeff, grouping_type])	type primitive `SparsePauliOp`
`add`(other)	Return Operator addition of self and other, overloaded by `+`.
`adjoint`()	Return a new Operator equal to the Operator’s adjoint (conjugate transpose), overloaded by `~`.
`assign_parameters`(param_dict)	Binds scalar values to any Terra `Parameters` in the coefficients or primitives of the Operator, or substitutes one `Parameter` for another.
`bind_parameters`(param_dict)	Same as assign_parameters, but maintained for consistency with QuantumCircuit in Terra (which has both assign_parameters and bind_parameters).
`compose`(other[, permutation, front])	Return Operator Composition between self and other (linear algebra-style: A@B(x) = A(B(x))), overloaded by `@`.
`copy`()	Return a deep copy of the Operator.
`equals`(other)	Evaluate Equality between Operators, overloaded by `==`.
`eval`([front])	Evaluate the Operator’s underlying function, either on a binary string or another Operator.
`exp_i`()	Return a `CircuitOp` equivalent to e^-iH for this operator H.
`from_list`(pauli_list[, coeff])	Construct from a pauli_list with the form [(pauli_str, coeffs)]
`is_zero`()	Return this operator is zero operator or not.
`log_i`([massive])	Return a `MatrixOp` equivalent to log(H)/-i for this operator H.
`matrix_iter`([sparse])	Return a matrix representation iterator.
`mul`(scalar)	Returns the scalar multiplication of the Operator, overloaded by `*`, including support for Terra’s `Parameters`, which can be bound to values later (via `bind_parameters`).
`neg`()	Return the Operator’s negation, effectively just multiplying by -1.0, overloaded by `-`.
`permute`(permutation)	Permutes the sequence of `PauliSumOp`.
`power`(exponent)	Return Operator composed with self multiple times, overloaded by `**`.
`primitive_strings`()	Return a set of strings describing the primitives contained in the Operator.
`reduce`([atol, rtol])	Simplify the primitive `SparsePauliOp`.
`tensor`(other)	Return tensor product between self and other, overloaded by `^`.
`tensorpower`(other)	Return tensor product with self multiple times, overloaded by `^`.
`to_circuit`()	Returns a `QuantumCircuit` equivalent to this Operator.
`to_circuit_op`()	Returns a `CircuitOp` equivalent to this Operator.
`to_instruction`()	Returns an `Instruction` equivalent to this Operator.
`to_matrix`([massive])	Return NumPy representation of the Operator.
`to_matrix_op`([massive])	Returns a `MatrixOp` equivalent to this Operator.
`to_pauli_op`([massive])	Returns a sum of `PauliOp` s equivalent to this Operator.
`to_spmatrix`()	Returns SciPy sparse matrix representation of the `PauliSumOp`.

Attributes

`INDENTATION`
`coeff`	The scalar coefficient multiplying the Operator.
`coeffs`	Return the Pauli coefficients.
`grouping_type`	Type of Grouping
`instance_id`	Return the unique instance id.
`num_qubits`	The number of qubits over which the Operator is defined.
`parameters`	Return a set of Parameter objects contained in the Operator.
`primitive`	The primitive defining the underlying function of the Operator.

add(other)[source]¶

Return Operator addition of self and other, overloaded by +.

Parameters: other (OperatorBase) – An OperatorBase with the same number of qubits as self, and in the same ‘Operator’, ‘State function’, or ‘Measurement’ category as self (i.e. the same type of underlying function).
Return type: OperatorBase
Returns: An OperatorBase equivalent to the sum of self and other.

adjoint()[source]¶

Return a new Operator equal to the Operator’s adjoint (conjugate transpose), overloaded by ~. For StateFns, this also turns the StateFn into a measurement.

Return type: PauliSumOp
Returns: An OperatorBase equivalent to the adjoint of self.

assign_parameters(param_dict)¶

Binds scalar values to any Terra Parameters in the coefficients or primitives of the Operator, or substitutes one Parameter for another. This method differs from Terra’s assign_parameters in that it also supports lists of values to assign for a give Parameter, in which case self will be copied for each parameterization in the binding list(s), and all the copies will be returned in an OpList. If lists of parameterizations are used, every Parameter in the param_dict must have the same length list of parameterizations.

Parameters: param_dict (dict) – The dictionary of Parameters to replace, and values or lists of values by which to replace them.
Return type: OperatorBase
Returns: The OperatorBase with the Parameters in self replaced by the values or Parameters in param_dict. If param_dict contains parameterization lists, this OperatorBase is an OpList.

bind_parameters(param_dict)¶

Same as assign_parameters, but maintained for consistency with QuantumCircuit in Terra (which has both assign_parameters and bind_parameters).

Return type: OperatorBase

property coeff¶

The scalar coefficient multiplying the Operator.

Return type: Union[complex, ParameterExpression]
Returns: The coefficient.

property coeffs¶: Return the Pauli coefficients.

compose(other, permutation=None, front=False)[source]¶

Return Operator Composition between self and other (linear algebra-style: A@B(x) = A(B(x))), overloaded by @.

Note: You must be conscious of Quantum Circuit vs. Linear Algebra ordering conventions. Meaning, X.compose(Y) produces an X∘Y on qubit 0, but would produce a QuantumCircuit which looks like

-[Y]-[X]-

Because Terra prints circuits with the initial state at the left side of the circuit.

Parameters

other (OperatorBase) – The OperatorBase with which to compose self.
permutation (Optional[List[int]]) – List[int] which defines permutation on other operator.
front (bool) – If front==True, return other.compose(self).

Return type

OperatorBase

Returns

An OperatorBase equivalent to the function composition of self and other.

copy()¶

Return a deep copy of the Operator.

Return type: OperatorBase

equals(other)[source]¶

Evaluate Equality between Operators, overloaded by ==. Only returns True if self and other are of the same representation (e.g. a DictStateFn and CircuitStateFn will never be equal, even if their vector representations are equal), their underlying primitives are equal (this means for ListOps, OperatorStateFns, or EvolvedOps the equality is evaluated recursively downwards), and their coefficients are equal.

Parameters: other (OperatorBase) – The OperatorBase to compare to self.
Return type: bool
Returns: A bool equal to the equality of self and other.

eval(front=None)[source]¶

Evaluate the Operator’s underlying function, either on a binary string or another Operator. A square binary Operator can be defined as a function taking a binary function to another binary function. This method returns the value of that function for a given StateFn or binary string. For example, op.eval('0110').eval('1110') can be seen as querying the Operator’s matrix representation by row 6 and column 14, and will return the complex value at those “indices.” Similarly for a StateFn, op.eval('1011') will return the complex value at row 11 of the vector representation of the StateFn, as all StateFns are defined to be evaluated from Zero implicitly (i.e. it is as if .eval('0000') is already called implicitly to always “indexing” from column 0).

If front is None, the matrix-representation of the operator is returned.

Parameters: front (Union[str, Dict[str, complex], ndarray, OperatorBase, Statevector, None]) – The bitstring, dict of bitstrings (with values being coefficients), or StateFn to evaluated by the Operator’s underlying function, or None.
Return type: Union[OperatorBase, complex]
Returns: The output of the Operator’s evaluation function. If self is a StateFn, the result is a float or complex. If self is an Operator (PrimitiveOp, ComposedOp, SummedOp, EvolvedOp, etc.), the result is a StateFn. If front is None, the matrix-representation of the operator is returned, which is a MatrixOp for the operators and a VectorStateFn for state-functions. If either self or front contain proper ListOps (not ListOp subclasses), the result is an n-dimensional list of complex or StateFn results, resulting from the recursive evaluation by each OperatorBase in the ListOps.

exp_i()[source]¶

Return a CircuitOp equivalent to e^-iH for this operator H.

Return type: OperatorBase

classmethod from_list(pauli_list, coeff=1.0)[source]¶

Construct from a pauli_list with the form [(pauli_str, coeffs)]

Parameters

pauli_list (List[Tuple[str, complex]]) – A list of Tuple of pauli_str and coefficient.
coeff (Union[complex, ParameterExpression]) – A coefficient multiplying the primitive.

Return type

PauliSumOp

Returns

The PauliSumOp constructed from the pauli_list.

property grouping_type¶

Type of Grouping

Type: Returns
Return type: str

property instance_id¶

Return the unique instance id.

Return type: int

is_zero()[source]¶

Return this operator is zero operator or not.

Return type: bool

log_i(massive=False)¶

Return a MatrixOp equivalent to log(H)/-i for this operator H. This function is the effective inverse of exp_i, equivalent to finding the Hermitian Operator which produces self when exponentiated.

Return type: OperatorBase

matrix_iter(sparse=False)[source]¶

Return a matrix representation iterator.

This is a lazy iterator that converts each term in the PauliSumOp into a matrix as it is used. To convert to a single matrix use the to_matrix() method.

Parameters: sparse (bool) – optionally return sparse CSR matrices if True, otherwise return Numpy array matrices (Default: False)
Returns: matrix iterator object for the PauliTable.
Return type: MatrixIterator

mul(scalar)[source]¶

Returns the scalar multiplication of the Operator, overloaded by *, including support for Terra’s Parameters, which can be bound to values later (via bind_parameters).

Parameters: scalar (Union[complex, ParameterExpression]) – The real or complex scalar by which to multiply the Operator, or the ParameterExpression to serve as a placeholder for a scalar factor.
Return type: OperatorBase
Returns: An OperatorBase equivalent to product of self and scalar.

neg()¶

Return the Operator’s negation, effectively just multiplying by -1.0, overloaded by -.

Return type: OperatorBase
Returns: An OperatorBase equivalent to the negation of self.

property num_qubits¶

The number of qubits over which the Operator is defined. If op.num_qubits == 5, then op.eval('1' * 5) will be valid, but op.eval('11') will not.

Return type: int
Returns: The number of qubits accepted by the Operator’s underlying function.

property parameters¶: Return a set of Parameter objects contained in the Operator.

permute(permutation)[source]¶

Permutes the sequence of PauliSumOp.

Parameters: permutation (List[int]) – A list defining where each Pauli should be permuted. The Pauli at index j of the primitive should be permuted to position permutation[j].
Return type: PauliSumOp
Returns: A new PauliSumOp representing the permuted operator. For operator (X ^ Y ^ Z) and indices=[1,2,4], it returns (X ^ I ^ Y ^ Z ^ I).
Raises: OpflowError – if indices do not define a new index for each qubit.

power(exponent)¶

Return Operator composed with self multiple times, overloaded by **.

Parameters: exponent (int) – The int number of times to compose self with itself.
Return type: OperatorBase
Returns: An OperatorBase equivalent to self composed with itself exponent times.

property primitive¶

The primitive defining the underlying function of the Operator.

Return type: Union[QuantumCircuit, Operator, Pauli, SparsePauliOp, OperatorBase]
Returns: The primitive object.

primitive_strings()[source]¶

Return a set of strings describing the primitives contained in the Operator. For example, {'QuantumCircuit', 'Pauli'}. For hierarchical Operators, such as ListOps, this can help illuminate the primitives represented in the various recursive levels, and therefore which conversions can be applied.

Return type: Set[str]
Returns: A set of strings describing the primitives contained within the Operator.

reduce(atol=None, rtol=None)[source]¶

Simplify the primitive SparsePauliOp.

Parameters

atol (Optional[float]) – Absolute tolerance for checking if coefficients are zero (Default: 1e-8).
rtol (Optional[float]) – Relative tolerance for checking if coefficients are zero (Default: 1e-5).

Return type

PauliSumOp

Returns

The simplified PauliSumOp.

tensor(other)[source]¶

Return tensor product between self and other, overloaded by ^. Note: You must be conscious of Qiskit’s big-endian bit printing convention. Meaning, X.tensor(Y) produces an X on qubit 0 and an Y on qubit 1, or X⨂Y, but would produce a QuantumCircuit which looks like

-[Y]- -[X]-

Because Terra prints circuits and results with qubit 0 at the end of the string or circuit.

Parameters: other (OperatorBase) – The OperatorBase to tensor product with self.
Return type: Union[PauliSumOp, TensoredOp]
Returns: An OperatorBase equivalent to the tensor product of self and other.

tensorpower(other)¶

Return tensor product with self multiple times, overloaded by ^.

Parameters: other (int) – The int number of times to tensor product self with itself via tensorpower.
Return type: Union[OperatorBase, int]
Returns: An OperatorBase equivalent to the tensorpower of self by other.

to_circuit()¶

Returns a QuantumCircuit equivalent to this Operator.

Return type: QuantumCircuit

to_circuit_op()¶

Returns a CircuitOp equivalent to this Operator.

Return type: OperatorBase

to_instruction()[source]¶

Returns an Instruction equivalent to this Operator.

Return type: Instruction

to_matrix(massive=False)[source]¶

Return NumPy representation of the Operator. Represents the evaluation of the Operator’s underlying function on every combination of basis binary strings. Warn if more than 16 qubits to force having to set massive=True if such a large vector is desired.

Return type: ndarray
Returns: The NumPy ndarray equivalent to this Operator.

to_matrix_op(massive=False)¶

Returns a MatrixOp equivalent to this Operator.

Return type: OperatorBase

to_pauli_op(massive=False)[source]¶

Returns a sum of PauliOp s equivalent to this Operator.

Return type: Union[PauliOp, SummedOp]

to_spmatrix()[source]¶

Returns SciPy sparse matrix representation of the PauliSumOp.

Return type: spmatrix
Returns: CSR sparse matrix representation of the PauliSumOp.
Raises: ValueError – invalid parameters.