Add type hints to gates and QuantumCircuit

qiskit/circuit/gate.py

@@ -93,7 +93,7 @@ def _return_repeat(self, exponent: float) -> "Gate":
 
     def control(
         self,
-        num_ctrl_qubits: Optional[int] = 1,
+        num_ctrl_qubits: int = 1,
         label: Optional[str] = None,
         ctrl_state: Optional[Union[int, str]] = None,
     ):

qiskit/circuit/library/standard_gates/h.py

@@ -12,6 +12,7 @@
 
 """Hadamard gate."""
 
+from typing import Optional, Union
 import numpy
 from qiskit.circuit.controlledgate import ControlledGate
 from qiskit.circuit.gate import Gate
@@ -47,7 +48,7 @@ class HGate(Gate):
             \end{pmatrix}
     """
 
-    def __init__(self, label=None):
+    def __init__(self, label: Optional[str] = None):
         """Create new H gate."""
         super().__init__("h", 1, [], label=label)
 
@@ -67,7 +68,12 @@ def _define(self):
 
         self.definition = qc
 
-    def control(self, num_ctrl_qubits=1, label=None, ctrl_state=None):
+    def control(
+        self,
+        num_ctrl_qubits: int = 1,
+        label: Optional[str] = None,
+        ctrl_state: Optional[Union[int, str]] = None,
+    ):
         """Return a (multi-)controlled-H gate.
 
         One control qubit returns a CH gate.
@@ -158,7 +164,7 @@ class CHGate(ControlledGate):
         dtype=complex,
     )
 
-    def __init__(self, label=None, ctrl_state=None):
+    def __init__(self, label: Optional[str] = None, ctrl_state: Optional[Union[int, str]] = None):
         """Create new CH gate."""
         super().__init__(
             "ch", 2, [], num_ctrl_qubits=1, label=label, ctrl_state=ctrl_state, base_gate=HGate()

qiskit/circuit/library/standard_gates/i.py

@@ -12,6 +12,7 @@
 
 """Identity gate."""
 
+from typing import Optional
 import numpy
 from qiskit.circuit.gate import Gate
 
@@ -39,7 +40,7 @@ class IGate(Gate):
              └───┘
     """
 
-    def __init__(self, label=None):
+    def __init__(self, label: Optional[str] = None):
         """Create new Identity gate."""
         super().__init__("id", 1, [], label=label)
 

qiskit/circuit/library/standard_gates/iswap.py

@@ -12,6 +12,7 @@
 
 """iSWAP gate."""
 
+from typing import Optional
 import numpy as np
 from qiskit.circuit.gate import Gate
 from qiskit.circuit.quantumregister import QuantumRegister
@@ -75,9 +76,9 @@ class iSwapGate(Gate):
             \end{pmatrix}
     """
 
-    def __init__(self):
+    def __init__(self, label: Optional[str] = None):
         """Create new iSwap gate."""
-        super().__init__("iswap", 2, [])
+        super().__init__("iswap", 2, [], label=label)
 
     def _define(self):
         """

qiskit/circuit/library/standard_gates/ms.py

@@ -12,9 +12,11 @@
 
 """Global Mølmer–Sørensen gate."""
 
+from typing import Optional
 import warnings
 from qiskit.circuit.gate import Gate
 from qiskit.circuit.quantumregister import QuantumRegister
+from qiskit.circuit.parameterexpression import ParameterValueType
 
 
 class MSGate(Gate):
@@ -30,7 +32,7 @@ class MSGate(Gate):
     and is thus reduced to the RXXGate.
     """
 
-    def __init__(self, num_qubits, theta, label=None):
+    def __init__(self, num_qubits: int, theta: ParameterValueType, label: Optional[str] = None):
         """Create new MS gate."""
         warnings.warn(
             "The qiskit.circuit.library.standard_gates.ms import "

qiskit/circuit/library/standard_gates/multi_control_rotation_gates.py

@@ -14,9 +14,11 @@
 """
 
 from math import pi
+from typing import Optional, Union, Tuple, List
 from qiskit.circuit import QuantumCircuit, QuantumRegister, Qubit
 from qiskit.circuit.library.standard_gates.x import MCXGate
 from qiskit.circuit.library.standard_gates.u3 import _generate_gray_code
+from qiskit.circuit.parameterexpression import ParameterValueType
 from qiskit.exceptions import QiskitError
 
 
@@ -74,14 +76,20 @@ def _apply_mcu_graycode(circuit, theta, phi, lam, ctls, tgt, use_basis_gates):
         last_pattern = pattern
 
 
-def mcrx(self, theta, q_controls, q_target, use_basis_gates=False):
+def mcrx(
+    self,
+    theta: ParameterValueType,
+    q_controls: Union[QuantumRegister, List[Qubit]],
+    q_target: Qubit,
+    use_basis_gates: bool = False,
+):
     """
     Apply Multiple-Controlled X rotation gate
 
     Args:
         self (QuantumCircuit): The QuantumCircuit object to apply the mcrx gate on.
         theta (float): angle theta
-        q_controls (list(Qubit)): The list of control qubits
+        q_controls (QuantumRegister or list(Qubit)): The list of control qubits
         q_target (Qubit): The target qubit
         use_basis_gates (bool): use p, u, cx
 
@@ -134,7 +142,15 @@ def mcrx(self, theta, q_controls, q_target, use_basis_gates=False):
         )
 
 
-def mcry(self, theta, q_controls, q_target, q_ancillae=None, mode=None, use_basis_gates=False):
+def mcry(
+    self,
+    theta: ParameterValueType,
+    q_controls: Union[QuantumRegister, List[Qubit]],
+    q_target: Qubit,
+    q_ancillae: Optional[Union[QuantumRegister, Tuple[QuantumRegister, int]]] = None,
+    mode: str = None,
+    use_basis_gates=False,
+):
     """
     Apply Multiple-Controlled Y rotation gate
 
@@ -219,7 +235,13 @@ def mcry(self, theta, q_controls, q_target, q_ancillae=None, mode=None, use_basi
         raise QiskitError(f"Unrecognized mode for building MCRY circuit: {mode}.")
 
 
-def mcrz(self, lam, q_controls, q_target, use_basis_gates=False):
+def mcrz(
+    self,
+    lam: ParameterValueType,
+    q_controls: Union[QuantumRegister, List[Qubit]],
+    q_target: Qubit,
+    use_basis_gates: bool = False,
+):
     """
     Apply Multiple-Controlled Z rotation gate
 

qiskit/circuit/library/standard_gates/p.py

@@ -12,10 +12,12 @@
 
 """Phase Gate."""
 
+from typing import Optional, Union
 import numpy
 from qiskit.circuit.controlledgate import ControlledGate
 from qiskit.circuit.gate import Gate
 from qiskit.circuit.quantumregister import QuantumRegister
+from qiskit.circuit.parameterexpression import ParameterValueType
 
 
 class PhaseGate(Gate):
@@ -69,7 +71,7 @@ class PhaseGate(Gate):
         `1612.00858 <https://arxiv.org/abs/1612.00858>`_
     """
 
-    def __init__(self, theta, label=None):
+    def __init__(self, theta: ParameterValueType, label: Optional[str] = None):
         """Create new Phase gate."""
         super().__init__("p", 1, [theta], label=label)
 
@@ -83,7 +85,12 @@ def _define(self):
         qc.append(UGate(0, 0, self.params[0]), [0])
         self.definition = qc
 
-    def control(self, num_ctrl_qubits=1, label=None, ctrl_state=None):
+    def control(
+        self,
+        num_ctrl_qubits: int = 1,
+        label: Optional[str] = None,
+        ctrl_state: Optional[Union[int, str]] = None,
+    ):
         """Return a (multi-)controlled-Phase gate.
 
         Args:
@@ -153,7 +160,12 @@ class CPhaseGate(ControlledGate):
         phase difference.
     """
 
-    def __init__(self, theta, label=None, ctrl_state=None):
+    def __init__(
+        self,
+        theta: ParameterValueType,
+        label: Optional[str] = None,
+        ctrl_state: Optional[Union[str, int]] = None,
+    ):
         """Create new CPhase gate."""
         super().__init__(
             "cp",
@@ -185,7 +197,12 @@ def _define(self):
         qc.p(self.params[0] / 2, 1)
         self.definition = qc
 
-    def control(self, num_ctrl_qubits=1, label=None, ctrl_state=None):
+    def control(
+        self,
+        num_ctrl_qubits: int = 1,
+        label: Optional[str] = None,
+        ctrl_state: Optional[Union[str, int]] = None,
+    ):
         """Controlled version of this gate.
 
         Args:
@@ -242,7 +259,7 @@ class MCPhaseGate(ControlledGate):
         The singly-controlled-version of this gate.
     """
 
-    def __init__(self, lam, num_ctrl_qubits, label=None):
+    def __init__(self, lam: ParameterValueType, num_ctrl_qubits: int, label: Optional[str] = None):
         """Create new MCPhase gate."""
         super().__init__(
             "mcphase",
@@ -273,7 +290,12 @@ def _define(self):
             qc.data = definition
         self.definition = qc
 
-    def control(self, num_ctrl_qubits=1, label=None, ctrl_state=None):
+    def control(
+        self,
+        num_ctrl_qubits: int = 1,
+        label: Optional[str] = None,
+        ctrl_state: Optional[Union[str, int]] = None,
+    ):
         """Controlled version of this gate.
 
         Args:

qiskit/circuit/library/standard_gates/r.py

@@ -13,10 +13,12 @@
 """Rotation around an axis in x-y plane."""
 
 import math
+from typing import Optional
 import numpy
 from qiskit.qasm import pi
 from qiskit.circuit.gate import Gate
 from qiskit.circuit.quantumregister import QuantumRegister
+from qiskit.circuit.parameterexpression import ParameterValueType
 
 
 class RGate(Gate):
@@ -43,9 +45,11 @@ class RGate(Gate):
             \end{pmatrix}
     """
 
-    def __init__(self, theta, phi):
+    def __init__(
+        self, theta: ParameterValueType, phi: ParameterValueType, label: Optional[str] = None
+    ):
         """Create new r single-qubit gate."""
-        super().__init__("r", 1, [theta, phi])
+        super().__init__("r", 1, [theta, phi], label=label)
 
     def _define(self):
         """

qiskit/circuit/library/standard_gates/rx.py

@@ -13,11 +13,14 @@
 """Rotation around the X axis."""
 
 import math
+from typing import Optional, Union
 import numpy
+
 from qiskit.qasm import pi
 from qiskit.circuit.controlledgate import ControlledGate
 from qiskit.circuit.gate import Gate
 from qiskit.circuit.quantumregister import QuantumRegister
+from qiskit.circuit.parameterexpression import ParameterValueType
 
 
 class RXGate(Gate):
@@ -44,7 +47,7 @@ class RXGate(Gate):
             \end{pmatrix}
     """
 
-    def __init__(self, theta, label=None):
+    def __init__(self, theta: ParameterValueType, label: Optional[str] = None):
         """Create new RX gate."""
         super().__init__("rx", 1, [theta], label=label)
 
@@ -64,7 +67,12 @@ def _define(self):
 
         self.definition = qc
 
-    def control(self, num_ctrl_qubits=1, label=None, ctrl_state=None):
+    def control(
+        self,
+        num_ctrl_qubits: int = 1,
+        label: Optional[str] = None,
+        ctrl_state: Optional[Union[str, int]] = None,
+    ):
         """Return a (multi-)controlled-RX gate.
 
         Args:
@@ -151,7 +159,12 @@ class CRXGate(ControlledGate):
                 \end{pmatrix}
     """
 
-    def __init__(self, theta, label=None, ctrl_state=None):
+    def __init__(
+        self,
+        theta: ParameterValueType,
+        label: Optional[str] = None,
+        ctrl_state: Optional[Union[str, int]] = None,
+    ):
         """Create new CRX gate."""
         super().__init__(
             "crx",

qiskit/circuit/library/standard_gates/rxx.py

@@ -12,8 +12,10 @@
 
 """Two-qubit XX-rotation gate."""
 
+from typing import Optional
 from qiskit.circuit.gate import Gate
 from qiskit.circuit.quantumregister import QuantumRegister
+from qiskit.circuit.parameterexpression import ParameterValueType
 
 
 class RXXGate(Gate):
@@ -66,9 +68,9 @@ class RXXGate(Gate):
                                     \end{pmatrix}
     """
 
-    def __init__(self, theta):
+    def __init__(self, theta: ParameterValueType, label: Optional[str] = None):
         """Create new RXX gate."""
-        super().__init__("rxx", 2, [theta])
+        super().__init__("rxx", 2, [theta], label=label)
 
     def _define(self):
         """Calculate a subcircuit that implements this unitary."""