# C4XGate¶

class C4XGate(label=None, ctrl_state=None)[source]

Bases: qiskit.circuit.controlledgate.ControlledGate

The 4-qubit controlled X gate.

This implementation is based on Page 21, Lemma 7.5, of [1], with the use of the relative phase version of c3x, the rc3x [2].

References

[1] Barenco et al., 1995. https://arxiv.org/pdf/quant-ph/9503016.pdf [2] Maslov, 2015. https://arxiv.org/abs/1508.03273

Create a new 4-qubit controlled X gate.

Methods Defined Here

 control Controlled version of this gate. inverse Invert this gate.

Attributes

ctrl_state

Return the control state of the gate as a decimal integer.

Return type

int

decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition

Return definition in terms of other basic gates. If the gate has open controls, as determined from self.ctrl_state, the returned definition is conjugated with X without changing the internal _definition.

Return type

List

duration

Get the duration.

label

Return instruction label

Return type

str

name

Get name of gate. If the gate has open controls the gate name will become:

<original_name_o<ctrl_state>

where <original_name> is the gate name for the default case of closed control qubits and <ctrl_state> is the integer value of the control state for the gate.

Return type

str

num_ctrl_qubits

Get number of control qubits.

Returns

The number of control qubits for the gate.

Return type

int

params

Get parameters from base_gate.

Returns

List of gate parameters.

Return type

list

Raises

CircuitError – Controlled gate does not define a base gate

unit

Get the time unit of duration.