UCGate

class qiskit.circuit.library.UCGate(gate_list, up_to_diagonal=False)

Bases: Gate

Uniformly controlled gate (also called multiplexed gate).

|i\rangle

2\times 2

\begin{pmatrix} U_0 & 0 & \cdots & 0 \\ 0 & U_1 & \cdots & 0 \\ \vdots & & \ddots & \vdots \\ 0 & 0 & \cdots & U_{2^{k-1}} \end{pmatrix}.

The decomposition is based on Ref. [1].

References:

[1] Bergholm et al., Quantum circuits with uniformly controlled one-qubit gates (2005).

Phys. Rev. A 71, 052330 .

Parameters

gate_list (list[np.ndarray]) – List of two qubit unitaries $[U_0, ..., U_{2^{k-1}}]$ , where each single-qubit unitary $U_i$ is given as a $2 \times 2$ numpy array.
up_to_diagonal (bool) – Determines if the gate is implemented up to a diagonal. or if it is decomposed completely (default: False). If the UCGate $U$ is decomposed up to a diagonal $D$ , this means that the circuit implements a unitary $U'$ such that $D U' = U$ .

Raises

QiskitError - in case of bad input to the constructor

Attributes

Get the base class of this instruction. This is guaranteed to be in the inheritance tree of self .

The “base class” of an instruction is the lowest class in its inheritance tree that the object should be considered entirely compatible with for _all_ circuit applications. This typically means that the subclass is defined purely to offer some sort of programmer convenience over the base class, and the base class is the “true” class for a behavioral perspective. In particular, you should not override base_class if you are defining a custom version of an instruction that will be implemented differently by hardware, such as an alternative measurement strategy, or a version of a parametrized gate with a particular set of parameters for the purposes of distinguishing it in a Target from the full parametrized gate.

This is often exactly equivalent to type(obj), except in the case of singleton instances of standard-library instructions. These singleton instances are special subclasses of their base class, and this property will return that base. For example:

>>> isinstance(XGate(), XGate)
True
>>> type(XGate()) is XGate
False
>>> XGate().base_class is XGate
True

In general, you should not rely on the precise class of an instruction; within a given circuit, it is expected that Instruction.name should be a more suitable discriminator in most situations.

The classical condition on the instruction.

Get Clbits in condition.

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

Return definition in terms of other basic gates.

Get the duration.

Return instruction label

Is this instance is a mutable unique instance or not.

If this attribute is False the gate instance is a shared singleton and is not mutable.

Return the name.

Return the number of clbits.

Return the number of qubits.

The parameters of this Instruction . Ideally these will be gate angles.

Get the time unit of duration.

inverse(annotated=False)

Return the inverse.

This does not re-compute the decomposition for the multiplexer with the inverse of the gates but simply inverts the existing decomposition.

Return type

Gate

validate_parameter(parameter)

Uniformly controlled gate parameter has to be an ndarray.

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