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---
title: SparsePauliOp
description: API reference for qiskit.quantum_info.SparsePauliOp
in_page_toc_min_heading_level: 1
python_api_type: class
python_api_name: qiskit.quantum_info.SparsePauliOp
---
# qiskit.quantum\_info.SparsePauliOp
<Class id="qiskit.quantum_info.SparsePauliOp" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.17/qiskit/quantum_info/operators/symplectic/sparse_pauli_op.py" signature="SparsePauliOp(data, coeffs=None)" modifiers="class">
Sparse N-qubit operator in a Pauli basis representation.
This is a sparse representation of an N-qubit matrix [`Operator`](qiskit.quantum_info.Operator "qiskit.quantum_info.Operator") in terms of N-qubit [`PauliTable`](qiskit.quantum_info.PauliTable "qiskit.quantum_info.PauliTable") and complex coefficients.
It can be used for performing operator arithmetic for hundred of qubits if the number of non-zero Pauli basis terms is sufficiently small.
The Pauli basis components are stored as a [`PauliTable`](qiskit.quantum_info.PauliTable "qiskit.quantum_info.PauliTable") object and can be accessed using the [`table`](#qiskit.quantum_info.SparsePauliOp.table "qiskit.quantum_info.SparsePauliOp.table") attribute. The coefficients are stored as a complex Numpy array vector and can be accessed using the [`coeffs`](#qiskit.quantum_info.SparsePauliOp.coeffs "qiskit.quantum_info.SparsePauliOp.coeffs") attribute.
Initialize an operator object.
**Parameters**
* **data** ([*PauliTable*](qiskit.quantum_info.PauliTable "qiskit.quantum_info.PauliTable")) Pauli table of terms.
* **coeffs** (*np.ndarray*) complex coefficients for Pauli terms.
**Raises**
**QiskitError** If the input data or coeffs are invalid.
### \_\_init\_\_
<Function id="qiskit.quantum_info.SparsePauliOp.__init__" signature="__init__(data, coeffs=None)">
Initialize an operator object.
**Parameters**
* **data** ([*PauliTable*](qiskit.quantum_info.PauliTable "qiskit.quantum_info.PauliTable")) Pauli table of terms.
* **coeffs** (*np.ndarray*) complex coefficients for Pauli terms.
**Raises**
**QiskitError** If the input data or coeffs are invalid.
</Function>
## Methods
| | |
| ---------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------- |
| [`__init__`](#qiskit.quantum_info.SparsePauliOp.__init__ "qiskit.quantum_info.SparsePauliOp.__init__")(data\[, coeffs]) | Initialize an operator object. |
| [`adjoint`](#qiskit.quantum_info.SparsePauliOp.adjoint "qiskit.quantum_info.SparsePauliOp.adjoint")() | Return the adjoint of the Operator. |
| [`compose`](#qiskit.quantum_info.SparsePauliOp.compose "qiskit.quantum_info.SparsePauliOp.compose")(other\[, qargs, front]) | Return the operator composition with another SparsePauliOp. |
| [`conjugate`](#qiskit.quantum_info.SparsePauliOp.conjugate "qiskit.quantum_info.SparsePauliOp.conjugate")() | Return the conjugate of the SparsePauliOp. |
| [`copy`](#qiskit.quantum_info.SparsePauliOp.copy "qiskit.quantum_info.SparsePauliOp.copy")() | Make a deep copy of current operator. |
| [`dot`](#qiskit.quantum_info.SparsePauliOp.dot "qiskit.quantum_info.SparsePauliOp.dot")(other\[, qargs]) | Return the right multiplied operator self \* other. |
| [`expand`](#qiskit.quantum_info.SparsePauliOp.expand "qiskit.quantum_info.SparsePauliOp.expand")(other) | Return the reverse-order tensor product with another SparsePauliOp. |
| [`from_list`](#qiskit.quantum_info.SparsePauliOp.from_list "qiskit.quantum_info.SparsePauliOp.from_list")(obj) | Construct from a list \[(pauli\_str, coeffs)] |
| [`from_operator`](#qiskit.quantum_info.SparsePauliOp.from_operator "qiskit.quantum_info.SparsePauliOp.from_operator")(obj\[, atol, rtol]) | Construct from an Operator objector. |
| [`input_dims`](#qiskit.quantum_info.SparsePauliOp.input_dims "qiskit.quantum_info.SparsePauliOp.input_dims")(\[qargs]) | Return tuple of input dimension for specified subsystems. |
| [`is_unitary`](#qiskit.quantum_info.SparsePauliOp.is_unitary "qiskit.quantum_info.SparsePauliOp.is_unitary")(\[atol, rtol]) | Return True if operator is a unitary matrix. |
| [`label_iter`](#qiskit.quantum_info.SparsePauliOp.label_iter "qiskit.quantum_info.SparsePauliOp.label_iter")() | Return a label representation iterator. |
| [`matrix_iter`](#qiskit.quantum_info.SparsePauliOp.matrix_iter "qiskit.quantum_info.SparsePauliOp.matrix_iter")(\[sparse]) | Return a matrix representation iterator. |
| [`output_dims`](#qiskit.quantum_info.SparsePauliOp.output_dims "qiskit.quantum_info.SparsePauliOp.output_dims")(\[qargs]) | Return tuple of output dimension for specified subsystems. |
| [`power`](#qiskit.quantum_info.SparsePauliOp.power "qiskit.quantum_info.SparsePauliOp.power")(n) | Return the compose of a operator with itself n times. |
| [`reshape`](#qiskit.quantum_info.SparsePauliOp.reshape "qiskit.quantum_info.SparsePauliOp.reshape")(\[input\_dims, output\_dims, num\_qubits]) | Return a shallow copy with reshaped input and output subsystem dimensions. |
| [`simplify`](#qiskit.quantum_info.SparsePauliOp.simplify "qiskit.quantum_info.SparsePauliOp.simplify")(\[atol, rtol]) | Simplify PauliTable by combining duplicates and removing zeros. |
| [`tensor`](#qiskit.quantum_info.SparsePauliOp.tensor "qiskit.quantum_info.SparsePauliOp.tensor")(other) | Return the tensor product with another SparsePauliOp. |
| [`to_list`](#qiskit.quantum_info.SparsePauliOp.to_list "qiskit.quantum_info.SparsePauliOp.to_list")(\[array]) | Convert to a list Pauli string labels and coefficients. |
| [`to_matrix`](#qiskit.quantum_info.SparsePauliOp.to_matrix "qiskit.quantum_info.SparsePauliOp.to_matrix")(\[sparse]) | Convert to a dense or sparse matrix. |
| [`to_operator`](#qiskit.quantum_info.SparsePauliOp.to_operator "qiskit.quantum_info.SparsePauliOp.to_operator")() | Convert to a matrix Operator object |
| [`transpose`](#qiskit.quantum_info.SparsePauliOp.transpose "qiskit.quantum_info.SparsePauliOp.transpose")() | Return the transpose of the SparsePauliOp. |
## Attributes
| | |
| ------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------- |
| [`atol`](#qiskit.quantum_info.SparsePauliOp.atol "qiskit.quantum_info.SparsePauliOp.atol") | Default absolute tolerance parameter for float comparisons. |
| [`coeffs`](#qiskit.quantum_info.SparsePauliOp.coeffs "qiskit.quantum_info.SparsePauliOp.coeffs") | Return the Pauli coefficients. |
| [`dim`](#qiskit.quantum_info.SparsePauliOp.dim "qiskit.quantum_info.SparsePauliOp.dim") | Return tuple (input\_shape, output\_shape). |
| [`num_qubits`](#qiskit.quantum_info.SparsePauliOp.num_qubits "qiskit.quantum_info.SparsePauliOp.num_qubits") | Return the number of qubits if a N-qubit operator or None otherwise. |
| [`qargs`](#qiskit.quantum_info.SparsePauliOp.qargs "qiskit.quantum_info.SparsePauliOp.qargs") | Return the qargs for the operator. |
| [`rtol`](#qiskit.quantum_info.SparsePauliOp.rtol "qiskit.quantum_info.SparsePauliOp.rtol") | Default relative tolerance parameter for float comparisons. |
| [`size`](#qiskit.quantum_info.SparsePauliOp.size "qiskit.quantum_info.SparsePauliOp.size") | The number of Pauli of Pauli terms in the operator. |
| [`table`](#qiskit.quantum_info.SparsePauliOp.table "qiskit.quantum_info.SparsePauliOp.table") | Return the the PauliTable. |
### adjoint
<Function id="qiskit.quantum_info.SparsePauliOp.adjoint" signature="adjoint()">
Return the adjoint of the Operator.
</Function>
### atol
<Attribute id="qiskit.quantum_info.SparsePauliOp.atol">
Default absolute tolerance parameter for float comparisons.
</Attribute>
### coeffs
<Attribute id="qiskit.quantum_info.SparsePauliOp.coeffs">
Return the Pauli coefficients.
</Attribute>
### compose
<Function id="qiskit.quantum_info.SparsePauliOp.compose" signature="compose(other, qargs=None, front=False)">
Return the operator composition with another SparsePauliOp.
**Parameters**
* **other** ([*SparsePauliOp*](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")) a SparsePauliOp object.
* **qargs** (*list or None*) Optional, a list of subsystem positions to apply other on. If None apply on all subsystems (default: None).
* **front** (*bool*) If True compose using right operator multiplication, instead of left multiplication \[default: False].
**Returns**
The composed SparsePauliOp.
**Return type**
[SparsePauliOp](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")
**Raises**
**QiskitError** if other cannot be converted to an operator, or has incompatible dimensions for specified subsystems.
<Admonition title="Note" type="note">
Composition (`&`) by default is defined as left matrix multiplication for matrix operators, while [`dot()`](#qiskit.quantum_info.SparsePauliOp.dot "qiskit.quantum_info.SparsePauliOp.dot") is defined as right matrix multiplication. That is that `A & B == A.compose(B)` is equivalent to `B.dot(A)` when `A` and `B` are of the same type.
Setting the `front=True` kwarg changes this to right matrix multiplication and is equivalent to the [`dot()`](#qiskit.quantum_info.SparsePauliOp.dot "qiskit.quantum_info.SparsePauliOp.dot") method `A.dot(B) == A.compose(B, front=True)`.
</Admonition>
</Function>
### conjugate
<Function id="qiskit.quantum_info.SparsePauliOp.conjugate" signature="conjugate()">
Return the conjugate of the SparsePauliOp.
</Function>
### copy
<Function id="qiskit.quantum_info.SparsePauliOp.copy" signature="copy()">
Make a deep copy of current operator.
</Function>
### dim
<Attribute id="qiskit.quantum_info.SparsePauliOp.dim">
Return tuple (input\_shape, output\_shape).
</Attribute>
### dot
<Function id="qiskit.quantum_info.SparsePauliOp.dot" signature="dot(other, qargs=None)">
Return the right multiplied operator self \* other.
**Parameters**
* **other** ([*Operator*](qiskit.quantum_info.Operator "qiskit.quantum_info.Operator")) an operator object.
* **qargs** (*list or None*) Optional, a list of subsystem positions to apply other on. If None apply on all subsystems (default: None).
**Returns**
The right matrix multiplied Operator.
**Return type**
[Operator](qiskit.quantum_info.Operator "qiskit.quantum_info.Operator")
</Function>
### expand
<Function id="qiskit.quantum_info.SparsePauliOp.expand" signature="expand(other)">
Return the reverse-order tensor product with another SparsePauliOp.
**Parameters**
**other** ([*SparsePauliOp*](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")) a SparsePauliOp object.
**Returns**
**the tensor product $b \otimes a$, where $a$**
is the current SparsePauliOp, and $b$ is the other SparsePauliOp.
**Return type**
[SparsePauliOp](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")
</Function>
### from\_list
<Function id="qiskit.quantum_info.SparsePauliOp.from_list" signature="from_list(obj)" modifiers="static">
Construct from a list \[(pauli\_str, coeffs)]
</Function>
### from\_operator
<Function id="qiskit.quantum_info.SparsePauliOp.from_operator" signature="from_operator(obj, atol=None, rtol=None)" modifiers="static">
Construct from an Operator objector.
Note that the cost of this construction is exponential as it involves taking inner products with every element of the N-qubit Pauli basis.
**Parameters**
* **obj** ([*Operator*](qiskit.quantum_info.Operator "qiskit.quantum_info.Operator")) an N-qubit operator.
* **atol** (*float*) Optional. Absolute tolerance for checking if coefficients are zero (Default: 1e-8).
* **rtol** (*float*) Optional. relative tolerance for checking if coefficients are zero (Default: 1e-5).
**Returns**
the SparsePauliOp representation of the operator.
**Return type**
[SparsePauliOp](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")
**Raises**
**QiskitError** if the input operator is not an N-qubit operator.
</Function>
### input\_dims
<Function id="qiskit.quantum_info.SparsePauliOp.input_dims" signature="input_dims(qargs=None)">
Return tuple of input dimension for specified subsystems.
</Function>
### is\_unitary
<Function id="qiskit.quantum_info.SparsePauliOp.is_unitary" signature="is_unitary(atol=None, rtol=None)">
Return True if operator is a unitary matrix.
**Parameters**
* **atol** (*float*) Optional. Absolute tolerance for checking if coefficients are zero (Default: 1e-8).
* **rtol** (*float*) Optional. relative tolerance for checking if coefficients are zero (Default: 1e-5).
**Returns**
True if the operator is unitary, False otherwise.
**Return type**
bool
</Function>
### label\_iter
<Function id="qiskit.quantum_info.SparsePauliOp.label_iter" signature="label_iter()">
Return a label representation iterator.
This is a lazy iterator that converts each term in the SparsePauliOp into a tuple (label, coeff). To convert the entire table to labels use the `to_labels()` method.
**Returns**
label iterator object for the PauliTable.
**Return type**
LabelIterator
</Function>
### matrix\_iter
<Function id="qiskit.quantum_info.SparsePauliOp.matrix_iter" signature="matrix_iter(sparse=False)">
Return a matrix representation iterator.
This is a lazy iterator that converts each term in the SparsePauliOp into a matrix as it is used. To convert to a single matrix use the [`to_matrix()`](#qiskit.quantum_info.SparsePauliOp.to_matrix "qiskit.quantum_info.SparsePauliOp.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
</Function>
### num\_qubits
<Attribute id="qiskit.quantum_info.SparsePauliOp.num_qubits">
Return the number of qubits if a N-qubit operator or None otherwise.
</Attribute>
### output\_dims
<Function id="qiskit.quantum_info.SparsePauliOp.output_dims" signature="output_dims(qargs=None)">
Return tuple of output dimension for specified subsystems.
</Function>
### power
<Function id="qiskit.quantum_info.SparsePauliOp.power" signature="power(n)">
Return the compose of a operator with itself n times.
**Parameters**
**n** (*int*) the number of times to compose with self (n>0).
**Returns**
the n-times composed operator.
**Return type**
[Pauli](qiskit.quantum_info.Pauli "qiskit.quantum_info.Pauli")
**Raises**
**QiskitError** if the input and output dimensions of the operator are not equal, or the power is not a positive integer.
</Function>
### qargs
<Attribute id="qiskit.quantum_info.SparsePauliOp.qargs">
Return the qargs for the operator.
</Attribute>
### reshape
<Function id="qiskit.quantum_info.SparsePauliOp.reshape" signature="reshape(input_dims=None, output_dims=None, num_qubits=None)">
Return a shallow copy with reshaped input and output subsystem dimensions.
**Parameters**
* **input\_dims** (*None or tuple*) new subsystem input dimensions. If None the original input dims will be preserved \[Default: None].
* **output\_dims** (*None or tuple*) new subsystem output dimensions. If None the original output dims will be preserved \[Default: None].
* **num\_qubits** (*None or int*) reshape to an N-qubit operator \[Default: None].
**Returns**
returns self with reshaped input and output dimensions.
**Return type**
BaseOperator
**Raises**
**QiskitError** if combined size of all subsystem input dimension or subsystem output dimensions is not constant.
</Function>
### rtol
<Attribute id="qiskit.quantum_info.SparsePauliOp.rtol">
Default relative tolerance parameter for float comparisons.
</Attribute>
### simplify
<Function id="qiskit.quantum_info.SparsePauliOp.simplify" signature="simplify(atol=None, rtol=None)">
Simplify PauliTable by combining duplicates and removing zeros.
**Parameters**
* **atol** (*float*) Optional. Absolute tolerance for checking if coefficients are zero (Default: 1e-8).
* **rtol** (*float*) Optional. relative tolerance for checking if coefficients are zero (Default: 1e-5).
**Returns**
the simplified SparsePauliOp operator.
**Return type**
[SparsePauliOp](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")
</Function>
### size
<Attribute id="qiskit.quantum_info.SparsePauliOp.size">
The number of Pauli of Pauli terms in the operator.
</Attribute>
### table
<Attribute id="qiskit.quantum_info.SparsePauliOp.table">
Return the the PauliTable.
</Attribute>
### tensor
<Function id="qiskit.quantum_info.SparsePauliOp.tensor" signature="tensor(other)">
Return the tensor product with another SparsePauliOp.
**Parameters**
**other** ([*SparsePauliOp*](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")) a SparsePauliOp object.
**Returns**
**the tensor product $a \otimes b$, where $a$**
is the current SparsePauliOp, and $b$ is the other SparsePauliOp.
**Return type**
[SparsePauliOp](#qiskit.quantum_info.SparsePauliOp "qiskit.quantum_info.SparsePauliOp")
<Admonition title="Note" type="note">
The tensor product can be obtained using the `^` binary operator. Hence `a.tensor(b)` is equivalent to `a ^ b`.
</Admonition>
</Function>
### to\_list
<Function id="qiskit.quantum_info.SparsePauliOp.to_list" signature="to_list(array=False)">
Convert to a list Pauli string labels and coefficients.
For operators with a lot of terms converting using the `array=True` kwarg will be more efficient since it allocates memory for the full Numpy array of labels in advance.
**Parameters**
**array** (*bool*) return a Numpy array if True, otherwise return a list (Default: False).
**Returns**
List of pairs (label, coeff) for rows of the PauliTable.
**Return type**
list or array
</Function>
### to\_matrix
<Function id="qiskit.quantum_info.SparsePauliOp.to_matrix" signature="to_matrix(sparse=False)">
Convert to a dense or sparse matrix.
**Parameters**
**sparse** (*bool*) if True return a sparse CSR matrix, otherwise return dense Numpy array (Default: False).
**Returns**
A dense matrix if sparse=False. csr\_matrix: A sparse matrix in CSR format if sparse=True.
**Return type**
array
</Function>
### to\_operator
<Function id="qiskit.quantum_info.SparsePauliOp.to_operator" signature="to_operator()">
Convert to a matrix Operator object
</Function>
### transpose
<Function id="qiskit.quantum_info.SparsePauliOp.transpose" signature="transpose()">
Return the transpose of the SparsePauliOp.
</Function>
</Class>