C4XGate
class qiskit.circuit.library.C4XGate(label=None, ctrl_state=None)
Bases: 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.
Attributes
condition_bits
Get Clbits in condition.
ctrl_state
Return the control state of the gate as a decimal integer.
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.
duration
Get the duration.
label
Return instruction label
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.
num_clbits
Return the number of clbits.
num_ctrl_qubits
num_qubits
Return the number of qubits.
params
Get parameters from base_gate.
Returns
List of gate parameters.
Return type
Raises
CircuitError – Controlled gate does not define a base gate
unit
Get the time unit of duration.
Methods
control
control(num_ctrl_qubits=1, label=None, ctrl_state=None)
Controlled version of this gate.
Parameters
- num_ctrl_qubits (int) – number of control qubits.
- label (str or None) – An optional label for the gate [Default: None]
- ctrl_state (int orstr or None) – control state expressed as integer, string (e.g. ‘110’), or None. If None, use all 1s.
Returns
controlled version of this gate.
Return type
inverse
inverse()
Invert this gate. The C4X is its own inverse.