ControlledGate¶
- class ControlledGate(name, num_qubits, params, label=None, num_ctrl_qubits=1, definition=None, ctrl_state=None, base_gate=None)[source]¶
Bases:
qiskit.circuit.gate.Gate
Controlled unitary gate.
Create a new ControlledGate. In the new gate the first
num_ctrl_qubits
of the gate are the controls.- Parameters
name (
str
) – The name of the gate.num_qubits (
int
) – The number of qubits the gate acts on.params (
List
) – A list of parameters for the gate.label (
Optional
[str
]) – An optional label for the gate.num_ctrl_qubits (
Optional
[int
]) – Number of control qubits.definition (
Optional
[QuantumCircuit
]) – A list of gate rules for implementing this gate. The elements of the list are tuples of (Gate()
, [qubit_list], [clbit_list]).ctrl_state (
Union
[int
,str
,None
]) – The control state in decimal or as a bitstring (e.g. ‘111’). If specified as a bitstring the length must equal num_ctrl_qubits, MSB on left. If None, use 2**num_ctrl_qubits-1.base_gate (
Optional
[Gate
]) – Gate object to be controlled.
- Raises
CircuitError – If
num_ctrl_qubits
>=num_qubits
.CircuitError – ctrl_state < 0 or ctrl_state > 2**num_ctrl_qubits.
Examples:
Create a controlled standard gate and apply it to a circuit.
from qiskit import QuantumCircuit, QuantumRegister from qiskit.circuit.library.standard_gates import HGate qr = QuantumRegister(3) qc = QuantumCircuit(qr) c3h_gate = HGate().control(2) qc.append(c3h_gate, qr) qc.draw()
q0_0: ──■── │ q0_1: ──■── ┌─┴─┐ q0_2: ┤ H ├ └───┘
Create a controlled custom gate and apply it to a circuit.
from qiskit import QuantumCircuit, QuantumRegister from qiskit.circuit.library.standard_gates import HGate qc1 = QuantumCircuit(2) qc1.x(0) qc1.h(1) custom = qc1.to_gate().control(2) qc2 = QuantumCircuit(4) qc2.append(custom, [0, 3, 1, 2]) qc2.draw()
q_0: ───────■─────── ┌──────┴──────┐ q_1: ┤0 ├ │ circuit-86 │ q_2: ┤1 ├ └──────┬──────┘ q_3: ───────■───────
Methods
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
Assemble a QasmQobjInstruction
Validation and handling of the arguments and its relationship.
Set a classical equality condition on this instruction between the register or cbit
classical
and valueval
.Return controlled version of gate.
Copy of the instruction.
Invert this gate by calling inverse on the base gate.
Return True .IFF.
Creates a unitary gate as gate^exponent.
Return a default OpenQASM string for the instruction.
Creates an instruction with gate repeated n amount of times.
For a composite instruction, reverse the order of sub-instructions.
Soft comparison between gates.
Return a Numpy.array for the gate unitary matrix.
Gate parameters should be int, float, or ParameterExpression
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_clbits¶
Return the number of clbits.
- num_ctrl_qubits¶
Get number of control qubits.
- Returns
The number of control qubits for the gate.
- Return type
int
- num_qubits¶
Return the number of qubits.
- 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.