SwapGate
class qiskit.circuit.library.SwapGate(*args, _force_mutable=False, **kwargs)
Bases: SingletonGate
The SWAP gate.
This is a symmetric and Clifford gate.
Can be applied to a QuantumCircuit with the swap() method.
Circuit symbol:
q_0: ─X─
│
q_1: ─X─Matrix Representation:
The gate is equivalent to a state swap and is a classical logic gate.
Create new SWAP gate.
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.
condition_bits
Get Clbits in condition.
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
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.
Methods
control
control(num_ctrl_qubits=1, label=None, ctrl_state=None, annotated=None)
Return a (multi-)controlled-SWAP gate.
One control returns a CSWAP (Fredkin) gate.
Parameters
- num_ctrl_qubits (int) – number of control qubits.
- label (str | None) – An optional label for the gate [Default:
None] - ctrl_state (str |int | None) – control state expressed as integer, string (e.g.``’110’
), or ``None. IfNone, use all 1s. - annotated (bool | None) – indicates whether the controlled gate should be implemented as an annotated gate. If
None, this is handled asFalse.
Returns
controlled version of this gate.
Return type
inverse
inverse(annotated=False)
Return inverse Swap gate (itself).
Parameters
annotated (bool) – when set to True, this is typically used to return an AnnotatedOperation with an inverse modifier set instead of a concrete Gate. However, for this class this argument is ignored as this gate is self-inverse.
Returns
inverse gate (self-inverse).
Return type