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# UnitaryGate

class `UnitaryGate(data, label=None)`

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Class quantum gates specified by a unitary matrix.

Example

We can create a unitary gate from a unitary matrix then add it to a quantum circuit. The matrix can also be directly applied to the quantum circuit, see `unitary()`.

``````from qiskit import QuantumCircuit
from qiskit.extensions import UnitaryGate

matrix = [[0, 0, 0, 1],
[0, 0, 1, 0],
[1, 0, 0, 0],
[0, 1, 0, 0]]
gate = UnitaryGate(matrix)

circuit = QuantumCircuit(2)
circuit.append(gate, [0, 1])``````

Create a gate from a numeric unitary matrix.

Parameters

• data (matrix or Operator) – unitary operator.
• label (str) – unitary name for backend [Default: None].

Raises

ExtensionError – if input data is not an N-qubit unitary operator.

## Methods

`UnitaryGate.add_decomposition(decomposition)`

Add a decomposition of the instruction to the SessionEquivalenceLibrary.

`UnitaryGate.adjoint()`

Return the adjoint of the unitary.

### assemble

`UnitaryGate.assemble()`

Assemble a QasmQobjInstruction

`UnitaryGate.broadcast_arguments(qargs, cargs)`

Validation and handling of the arguments and its relationship.

For example, `cx([q[0],q[1]], q[2])` means `cx(q[0], q[2]); cx(q[1], q[2])`. This method yields the arguments in the right grouping. In the given example:

``````in: [[q[0],q[1]], q[2]],[]
outs: [q[0], q[2]], []
[q[1], q[2]], []``````

• If len(qargs) == 1:

``[q[0], q[1]] -> [q[0]],[q[1]]``
• If len(qargs) == 2:

``````[[q[0], q[1]], [r[0], r[1]]] -> [q[0], r[0]], [q[1], r[1]]
[[q[0]], [r[0], r[1]]]       -> [q[0], r[0]], [q[0], r[1]]
[[q[0], q[1]], [r[0]]]       -> [q[0], r[0]], [q[1], r[0]]``````
• If len(qargs) >= 3:

``[q[0], q[1]], [r[0], r[1]],  ...] -> [q[0], r[0], ...], [q[1], r[1], ...]``

Parameters

• qargs (`List`) – List of quantum bit arguments.
• cargs (`List`) – List of classical bit arguments.

Return type

`Tuple`[`List`, `List`]

Returns

A tuple with single arguments.

Raises

CircuitError – If the input is not valid. For example, the number of arguments does not match the gate expectation.

### c_if

`UnitaryGate.c_if(classical, val)`

Set a classical equality condition on this instruction between the register or cbit `classical` and value `val`.

Note

This is a setter method, not an additive one. Calling this multiple times will silently override any previously set condition; it does not stack.

### conjugate

`UnitaryGate.conjugate()`

Return the conjugate of the unitary.

### control

`UnitaryGate.control(num_ctrl_qubits=1, label=None, ctrl_state=None)`

Return controlled version of gate

Parameters

• num_ctrl_qubits (int) – number of controls to add to gate (default=1)
• label (str) – optional gate label
• ctrl_state (int or str or None) – The control state in decimal or as a bit string (e.g. ‘1011’). If None, use 2**num_ctrl_qubits-1.

Returns

controlled version of gate.

Return type

UnitaryGate

Raises

• QiskitError – Invalid ctrl_state.
• ExtensionError – Non-unitary controlled unitary.

### copy

`UnitaryGate.copy(name=None)`

Copy of the instruction.

Parameters

name (str) – name to be given to the copied circuit, if None then the name stays the same.

Returns

a copy of the current instruction, with the name

updated if it was provided

Return type

qiskit.circuit.Instruction

### inverse

`UnitaryGate.inverse()`

Return the adjoint of the unitary.

### is_parameterized

`UnitaryGate.is_parameterized()`

Return True .IFF. instruction is parameterized else False

### power

`UnitaryGate.power(exponent)`

Creates a unitary gate as gate^exponent.

Parameters

exponent (float) – Gate^exponent

Returns

To which to_matrix is self.to_matrix^exponent.

Return type

qiskit.extensions.UnitaryGate

Raises

CircuitError – If Gate is not unitary

### qasm

`UnitaryGate.qasm()`

The qasm for a custom unitary gate This is achieved by adding a custom gate that corresponds to the definition of this gate. It gives the gate a random name if one hasn’t been given to it.

### repeat

`UnitaryGate.repeat(n)`

Creates an instruction with gate repeated n amount of times.

Parameters

n (int) – Number of times to repeat the instruction

Returns

Containing the definition.

Return type

qiskit.circuit.Instruction

Raises

CircuitError – If n < 1.

### reverse_ops

`UnitaryGate.reverse_ops()`

For a composite instruction, reverse the order of sub-instructions.

This is done by recursively reversing all sub-instructions. It does not invert any gate.

Returns

a new instruction with

sub-instructions reversed.

Return type

qiskit.circuit.Instruction

### soft_compare

`UnitaryGate.soft_compare(other)`

Soft comparison between gates. Their names, number of qubits, and classical bit numbers must match. The number of parameters must match. Each parameter is compared. If one is a ParameterExpression then it is not taken into account.

Parameters

other (instruction) – other instruction.

Returns

are self and other equal up to parameter expressions.

Return type

bool

### to_matrix

`UnitaryGate.to_matrix()`

Return a Numpy.array for the gate unitary matrix.

Returns

if the Gate subclass has a matrix definition.

Return type

np.ndarray

Raises

CircuitError – If a Gate subclass does not implement this method an exception will be raised when this base class method is called.

### transpose

`UnitaryGate.transpose()`

Return the transpose of the unitary.

### validate_parameter

`UnitaryGate.validate_parameter(parameter)`

Unitary gate parameter has to be an ndarray.

## Attributes

### condition_bits

Get Clbits in condition.

Return type

`List`[`Clbit`]

### decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

### definition

Return definition in terms of other basic gates.

### duration

Get the duration.

### label

Return instruction label

Return type

`str`

Return the name.

### num_clbits

Return the number of clbits.

### num_qubits

Return the number of qubits.

### params

return instruction params.

### unit

Get the time unit of duration.