qiskit-documentation/docs/api/qiskit/0.26/qiskit.quantum_info.CNOTDih...

351 lines
18 KiB
Plaintext
Raw Permalink Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

---
title: CNOTDihedral (v0.26)
description: API reference for qiskit.quantum_info.CNOTDihedral in qiskit v0.26
in_page_toc_min_heading_level: 1
python_api_type: class
python_api_name: qiskit.quantum_info.CNOTDihedral
---
<span id="qiskit-quantum-info-cnotdihedral" />
# qiskit.quantum\_info.CNOTDihedral
<Class id="qiskit.quantum_info.CNOTDihedral" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.17/qiskit/quantum_info/operators/dihedral/dihedral.py" signature="CNOTDihedral(data=None, num_qubits=None, validate=True)" modifiers="class">
An N-qubit operator from the CNOT-Dihedral group.
> The CNOT-Dihedral group is generated by the quantum gates, [`CXGate`](qiskit.circuit.library.CXGate "qiskit.circuit.library.CXGate"), [`TGate`](qiskit.circuit.library.TGate "qiskit.circuit.library.TGate"), and [`XGate`](qiskit.circuit.library.XGate "qiskit.circuit.library.XGate").
>
> **Representation**
>
> An $N$-qubit CNOT-Dihedral operator is stored as an affine function and a phase polynomial, based on the convention in references \[1, 2].
>
> The affine function consists of an $N \times N$ invertible binary matrix, and an $N$ binary vector.
>
> The phase polynomial is a polynomial of degree at most 3, in $N$ variables, whose coefficients are in the ring Z\_8 with 8 elements.
>
> ```python
> from qiskit import QuantumCircuit
> from qiskit.quantum_info import CNOTDihedral
>
> circ = QuantumCircuit(3)
> circ.cx(0, 1)
> circ.x(2)
> circ.t(1)
> circ.t(1)
> circ.t(1)
> elem = CNOTDihedral(circ)
>
> # Print the CNOTDihedral element
> print(elem)
> ```
>
> ```
> phase polynomial =
> 0 + 3*x_0 + 3*x_1 + 2*x_0*x_1
> affine function =
> (x_0,x_0 + x_1,x_2 + 1)
> ```
**Circuit Conversion**
> CNOTDihedral operators can be initialized from circuits containing *only* the following gates: [`IGate`](qiskit.circuit.library.IGate "qiskit.circuit.library.IGate"), [`XGate`](qiskit.circuit.library.XGate "qiskit.circuit.library.XGate"), [`YGate`](qiskit.circuit.library.YGate "qiskit.circuit.library.YGate"), [`ZGate`](qiskit.circuit.library.ZGate "qiskit.circuit.library.ZGate"), [`TGate`](qiskit.circuit.library.TGate "qiskit.circuit.library.TGate"), [`TdgGate`](qiskit.circuit.library.TdgGate "qiskit.circuit.library.TdgGate") [`SGate`](qiskit.circuit.library.SGate "qiskit.circuit.library.SGate"), [`SdgGate`](qiskit.circuit.library.SdgGate "qiskit.circuit.library.SdgGate"), [`CXGate`](qiskit.circuit.library.CXGate "qiskit.circuit.library.CXGate"), [`CZGate`](qiskit.circuit.library.CZGate "qiskit.circuit.library.CZGate"), [`SwapGate`](qiskit.circuit.library.SwapGate "qiskit.circuit.library.SwapGate"). They can be converted back into a [`QuantumCircuit`](qiskit.circuit.QuantumCircuit "qiskit.circuit.QuantumCircuit"), or [`Gate`](qiskit.circuit.Gate "qiskit.circuit.Gate") object using the [`to_circuit()`](#qiskit.quantum_info.CNOTDihedral.to_circuit "qiskit.quantum_info.CNOTDihedral.to_circuit") or `to_instruction()` methods respectively. Note that this decomposition is not necessarily optimal in terms of number of gates if the number of qubits is more than two.
>
> CNOTDihedral operators can also be converted to [`Operator`](qiskit.quantum_info.Operator "qiskit.quantum_info.Operator") objects using the [`to_operator()`](#qiskit.quantum_info.CNOTDihedral.to_operator "qiskit.quantum_info.CNOTDihedral.to_operator") method. This is done via decomposing to a circuit, and then simulating the circuit as a unitary operator.
>
> **References:**
>
> 1. Shelly Garion and Andrew W. Cross, *Synthesis of CNOT-Dihedral circuits with optimal number of two qubit gates*, [Quantum 4(369), 2020](https://quantum-journal.org/papers/q-2020-12-07-369/)
> 2. Andrew W. Cross, Easwar Magesan, Lev S. Bishop, John A. Smolin and Jay M. Gambetta, *Scalable randomised benchmarking of non-Clifford gates*, npj Quantum Inf 2, 16012 (2016).
Initialize a CNOTDihedral operator object.
**Parameters**
* **data** ([*CNOTDihedral*](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral") *or*[*QuantumCircuit*](qiskit.circuit.QuantumCircuit "qiskit.circuit.QuantumCircuit") *or*[*Instruction*](qiskit.circuit.Instruction "qiskit.circuit.Instruction")) Optional, operator to initialize.
* **num\_qubits** (*int*) Optional, initialize an empty CNOTDihedral operator.
* **validate** (*bool*) if True, validates the CNOTDihedral element.
**Raises**
* **QiskitError** if the type is invalid.
* **QiskitError** if validate=True and the CNOTDihedral element is invalid.
### \_\_init\_\_
<Function id="qiskit.quantum_info.CNOTDihedral.__init__" signature="__init__(data=None, num_qubits=None, validate=True)">
Initialize a CNOTDihedral operator object.
**Parameters**
* **data** ([*CNOTDihedral*](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral") *or*[*QuantumCircuit*](qiskit.circuit.QuantumCircuit "qiskit.circuit.QuantumCircuit") *or*[*Instruction*](qiskit.circuit.Instruction "qiskit.circuit.Instruction")) Optional, operator to initialize.
* **num\_qubits** (*int*) Optional, initialize an empty CNOTDihedral operator.
* **validate** (*bool*) if True, validates the CNOTDihedral element.
**Raises**
* **QiskitError** if the type is invalid.
* **QiskitError** if validate=True and the CNOTDihedral element is invalid.
</Function>
## Methods
| | |
| -------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------- |
| [`__init__`](#qiskit.quantum_info.CNOTDihedral.__init__ "qiskit.quantum_info.CNOTDihedral.__init__")(\[data, num\_qubits, validate]) | Initialize a CNOTDihedral operator object. |
| [`adjoint`](#qiskit.quantum_info.CNOTDihedral.adjoint "qiskit.quantum_info.CNOTDihedral.adjoint")() | Return the adjoint of the Operator. |
| [`compose`](#qiskit.quantum_info.CNOTDihedral.compose "qiskit.quantum_info.CNOTDihedral.compose")(other\[, qargs, front]) | Return the operator composition with another CNOTDihedral. |
| [`conjugate`](#qiskit.quantum_info.CNOTDihedral.conjugate "qiskit.quantum_info.CNOTDihedral.conjugate")() | Return the conjugate of the CNOTDihedral. |
| [`copy`](#qiskit.quantum_info.CNOTDihedral.copy "qiskit.quantum_info.CNOTDihedral.copy")() | Make a deep copy of current operator. |
| [`dot`](#qiskit.quantum_info.CNOTDihedral.dot "qiskit.quantum_info.CNOTDihedral.dot")(other\[, qargs]) | Return the right multiplied operator self \* other. |
| [`expand`](#qiskit.quantum_info.CNOTDihedral.expand "qiskit.quantum_info.CNOTDihedral.expand")(other) | Return the reverse-order tensor product with another CNOTDihedral. |
| [`input_dims`](#qiskit.quantum_info.CNOTDihedral.input_dims "qiskit.quantum_info.CNOTDihedral.input_dims")(\[qargs]) | Return tuple of input dimension for specified subsystems. |
| [`output_dims`](#qiskit.quantum_info.CNOTDihedral.output_dims "qiskit.quantum_info.CNOTDihedral.output_dims")(\[qargs]) | Return tuple of output dimension for specified subsystems. |
| [`power`](#qiskit.quantum_info.CNOTDihedral.power "qiskit.quantum_info.CNOTDihedral.power")(n) | Return the compose of a operator with itself n times. |
| [`reshape`](#qiskit.quantum_info.CNOTDihedral.reshape "qiskit.quantum_info.CNOTDihedral.reshape")(\[input\_dims, output\_dims, num\_qubits]) | Return a shallow copy with reshaped input and output subsystem dimensions. |
| [`tensor`](#qiskit.quantum_info.CNOTDihedral.tensor "qiskit.quantum_info.CNOTDihedral.tensor")(other) | Return the tensor product with another CNOTDihedral. |
| [`to_circuit`](#qiskit.quantum_info.CNOTDihedral.to_circuit "qiskit.quantum_info.CNOTDihedral.to_circuit")() | Return a QuantumCircuit implementing the CNOT-Dihedral element. |
| [`to_instruction`](#qiskit.quantum_info.CNOTDihedral.to_instruction "qiskit.quantum_info.CNOTDihedral.to_instruction")() | Return a Gate instruction implementing the CNOTDihedral object. |
| [`to_matrix`](#qiskit.quantum_info.CNOTDihedral.to_matrix "qiskit.quantum_info.CNOTDihedral.to_matrix")() | Convert operator to Numpy matrix. |
| [`to_operator`](#qiskit.quantum_info.CNOTDihedral.to_operator "qiskit.quantum_info.CNOTDihedral.to_operator")() | Convert to an Operator object. |
| [`transpose`](#qiskit.quantum_info.CNOTDihedral.transpose "qiskit.quantum_info.CNOTDihedral.transpose")() | Return the transpose of the CNOTDihedral. |
## Attributes
| | |
| ---------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------- |
| [`dim`](#qiskit.quantum_info.CNOTDihedral.dim "qiskit.quantum_info.CNOTDihedral.dim") | Return tuple (input\_shape, output\_shape). |
| [`num_qubits`](#qiskit.quantum_info.CNOTDihedral.num_qubits "qiskit.quantum_info.CNOTDihedral.num_qubits") | Return the number of qubits if a N-qubit operator or None otherwise. |
| [`qargs`](#qiskit.quantum_info.CNOTDihedral.qargs "qiskit.quantum_info.CNOTDihedral.qargs") | Return the qargs for the operator. |
### adjoint
<Function id="qiskit.quantum_info.CNOTDihedral.adjoint" signature="adjoint()">
Return the adjoint of the Operator.
</Function>
### compose
<Function id="qiskit.quantum_info.CNOTDihedral.compose" signature="compose(other, qargs=None, front=False)">
Return the operator composition with another CNOTDihedral.
**Parameters**
* **other** ([*CNOTDihedral*](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral")) a CNOTDihedral 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 CNOTDihedral.
**Return type**
[CNOTDihedral](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral")
**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.CNOTDihedral.dot "qiskit.quantum_info.CNOTDihedral.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.CNOTDihedral.dot "qiskit.quantum_info.CNOTDihedral.dot") method `A.dot(B) == A.compose(B, front=True)`.
</Admonition>
</Function>
### conjugate
<Function id="qiskit.quantum_info.CNOTDihedral.conjugate" signature="conjugate()">
Return the conjugate of the CNOTDihedral.
</Function>
### copy
<Function id="qiskit.quantum_info.CNOTDihedral.copy" signature="copy()">
Make a deep copy of current operator.
</Function>
### dim
<Attribute id="qiskit.quantum_info.CNOTDihedral.dim">
Return tuple (input\_shape, output\_shape).
</Attribute>
### dot
<Function id="qiskit.quantum_info.CNOTDihedral.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.CNOTDihedral.expand" signature="expand(other)">
Return the reverse-order tensor product with another CNOTDihedral.
**Parameters**
**other** ([*CNOTDihedral*](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral")) a CNOTDihedral object.
**Returns**
**the tensor product $b \otimes a$, where $a$**
is the current CNOTDihedral, and $b$ is the other CNOTDihedral.
**Return type**
[CNOTDihedral](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral")
</Function>
### input\_dims
<Function id="qiskit.quantum_info.CNOTDihedral.input_dims" signature="input_dims(qargs=None)">
Return tuple of input dimension for specified subsystems.
</Function>
### num\_qubits
<Attribute id="qiskit.quantum_info.CNOTDihedral.num_qubits">
Return the number of qubits if a N-qubit operator or None otherwise.
</Attribute>
### output\_dims
<Function id="qiskit.quantum_info.CNOTDihedral.output_dims" signature="output_dims(qargs=None)">
Return tuple of output dimension for specified subsystems.
</Function>
### power
<Function id="qiskit.quantum_info.CNOTDihedral.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.CNOTDihedral.qargs">
Return the qargs for the operator.
</Attribute>
### reshape
<Function id="qiskit.quantum_info.CNOTDihedral.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>
### tensor
<Function id="qiskit.quantum_info.CNOTDihedral.tensor" signature="tensor(other)">
Return the tensor product with another CNOTDihedral.
**Parameters**
**other** ([*CNOTDihedral*](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral")) a CNOTDihedral object.
**Returns**
**the tensor product $a \otimes b$, where $a$**
is the current CNOTDihedral, and $b$ is the other CNOTDihedral.
**Return type**
[CNOTDihedral](qiskit.ignis.verification.CNOTDihedral "qiskit.ignis.verification.CNOTDihedral")
<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\_circuit
<Function id="qiskit.quantum_info.CNOTDihedral.to_circuit" signature="to_circuit()">
Return a QuantumCircuit implementing the CNOT-Dihedral element.
**Returns**
a circuit implementation of the CNOTDihedral object.
**Return type**
[QuantumCircuit](qiskit.circuit.QuantumCircuit "qiskit.circuit.QuantumCircuit")
**References**
1. Shelly Garion and Andrew W. Cross, *Synthesis of CNOT-Dihedral circuits with optimal number of two qubit gates*, [Quantum 4(369), 2020](https://quantum-journal.org/papers/q-2020-12-07-369/)
2. Andrew W. Cross, Easwar Magesan, Lev S. Bishop, John A. Smolin and Jay M. Gambetta, *Scalable randomised benchmarking of non-Clifford gates*, npj Quantum Inf 2, 16012 (2016).
</Function>
### to\_instruction
<Function id="qiskit.quantum_info.CNOTDihedral.to_instruction" signature="to_instruction()">
Return a Gate instruction implementing the CNOTDihedral object.
</Function>
### to\_matrix
<Function id="qiskit.quantum_info.CNOTDihedral.to_matrix" signature="to_matrix()">
Convert operator to Numpy matrix.
</Function>
### to\_operator
<Function id="qiskit.quantum_info.CNOTDihedral.to_operator" signature="to_operator()">
Convert to an Operator object.
</Function>
### transpose
<Function id="qiskit.quantum_info.CNOTDihedral.transpose" signature="transpose()">
Return the transpose of the CNOTDihedral.
</Function>
</Class>