DiagonalGate
class qiskit.circuit.library.DiagonalGate(diag)
Bases: Gate
A generic diagonal quantum gate.
Matrix form:
Diagonal gates are useful as representations of Boolean functions, as they can map from to space. For example a phase oracle can be seen as a diagonal gate with on the diagonals. Such an oracle will induce a or :math`-1` phase on the amplitude of any corresponding basis state.
Diagonal gates appear in many classically hard oracular problems such as Forrelation or Hidden Shift circuits.
Diagonal gates are represented and simulated more efficiently than a dense unitary matrix.
The reference implementation is via the method described in Theorem 7 of [1]. The code is based on Emanuel Malvetti’s semester thesis at ETH in 2018, supervised by Raban Iten and Prof. Renato Renner.
Reference:
[1] Shende et al., Synthesis of Quantum Logic Circuits, 2009 arXiv:0406176
Parameters
diag (Sequence[complex]) – list of the diagonal entries (for a diagonal gate on qubits).
Attributes
base_class
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
TrueIn 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.
condition
The classical condition on the instruction.
The property qiskit.circuit.instruction.Instruction.condition is deprecated as of Qiskit 1.3.0. It will be removed in 2.0.0.
condition_bits
Get Clbits in condition.
The property qiskit.circuit.instruction.Instruction.condition_bits is deprecated as of Qiskit 1.3.0. It will be removed in 2.0.0.
decompositions
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
definition
Return definition in terms of other basic gates.
duration
Get the duration.
The property qiskit.circuit.instruction.Instruction.duration is deprecated as of Qiskit 1.3.0. It will be removed in Qiskit 2.0.0.
label
Return instruction label
mutable
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.
name
Return the name.
num_clbits
Return the number of clbits.
num_qubits
Return the number of qubits.
params
The parameters of this Instruction. Ideally these will be gate angles.
unit
Get the time unit of duration.
The property qiskit.circuit.instruction.Instruction.unit is deprecated as of Qiskit 1.3.0. It will be removed in Qiskit 2.0.0.
Methods
inverse
validate_parameter
validate_parameter(parameter)
Diagonal Gate parameter should accept complex (in addition to the Gate parameter types) and always return build-in complex.