C贸digo fuente para qiskit.circuit.library.standard_gates.ry

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# (C) Copyright IBM 2017.
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"""Rotation around the Y axis."""

import math
from math import pi
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


[documentos]class RYGate(Gate): r"""Single-qubit rotation about the Y axis. Can be applied to a :class:`~qiskit.circuit.QuantumCircuit` with the :meth:`~qiskit.circuit.QuantumCircuit.ry` method. **Circuit symbol:** .. parsed-literal:: 鈹屸攢鈹鈹鈹鈹鈹鈹鈹 q_0: 鈹 Ry(洗) 鈹 鈹斺攢鈹鈹鈹鈹鈹鈹鈹 **Matrix Representation:** .. math:: \newcommand{\th}{\frac{\theta}{2}} RY(\theta) = \exp\left(-i \th Y\right) = \begin{pmatrix} \cos\left(\th\right) & -\sin\left(\th\right) \\ \sin\left(\th\right) & \cos\left(\th\right) \end{pmatrix} """ def __init__(self, theta: ParameterValueType, label: Optional[str] = None): """Create new RY gate.""" super().__init__("ry", 1, [theta], label=label) def _define(self): """ gate ry(theta) a { r(theta, pi/2) a; } """ # pylint: disable=cyclic-import from qiskit.circuit.quantumcircuit import QuantumCircuit from .r import RGate q = QuantumRegister(1, "q") qc = QuantumCircuit(q, name=self.name) rules = [(RGate(self.params[0], pi / 2), [q[0]], [])] for instr, qargs, cargs in rules: qc._append(instr, qargs, cargs) self.definition = qc
[documentos] def control( self, num_ctrl_qubits: int = 1, label: Optional[str] = None, ctrl_state: Optional[Union[str, int]] = None, ): """Return a (multi-)controlled-RY gate. Args: num_ctrl_qubits (int): number of control qubits. label (str or None): An optional label for the gate [Default: None] ctrl_state (int or str or None): control state expressed as integer, string (e.g. '110'), or None. If None, use all 1s. Returns: ControlledGate: controlled version of this gate. """ if num_ctrl_qubits == 1: gate = CRYGate(self.params[0], label=label, ctrl_state=ctrl_state) gate.base_gate.label = self.label return gate return super().control(num_ctrl_qubits=num_ctrl_qubits, label=label, ctrl_state=ctrl_state)
[documentos] def inverse(self): r"""Return inverted RY gate. :math:`RY(\lambda)^{\dagger} = RY(-\lambda)` """ return RYGate(-self.params[0])
def __array__(self, dtype=None): """Return a numpy.array for the RY gate.""" cos = math.cos(self.params[0] / 2) sin = math.sin(self.params[0] / 2) return numpy.array([[cos, -sin], [sin, cos]], dtype=dtype)
[documentos] def power(self, exponent: float): """Raise gate to a power.""" (theta,) = self.params return RYGate(exponent * theta)
[documentos]class CRYGate(ControlledGate): r"""Controlled-RY gate. Can be applied to a :class:`~qiskit.circuit.QuantumCircuit` with the :meth:`~qiskit.circuit.QuantumCircuit.cry` method. **Circuit symbol:** .. parsed-literal:: q_0: 鈹鈹鈹鈹鈻犫攢鈹鈹鈹 鈹屸攢鈹鈹鈹粹攢鈹鈹鈹 q_1: 鈹 Ry(洗) 鈹 鈹斺攢鈹鈹鈹鈹鈹鈹鈹 **Matrix representation:** .. math:: \newcommand{\th}{\frac{\theta}{2}} CRY(\theta)\ q_0, q_1 = I \otimes |0\rangle\langle 0| + RY(\theta) \otimes |1\rangle\langle 1| = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & \cos\left(\th\right) & 0 & -\sin\left(\th\right) \\ 0 & 0 & 1 & 0 \\ 0 & \sin\left(\th\right) & 0 & \cos\left(\th\right) \end{pmatrix} .. note:: In Qiskit's convention, higher qubit indices are more significant (little endian convention). In many textbooks, controlled gates are presented with the assumption of more significant qubits as control, which in our case would be q_1. Thus a textbook matrix for this gate will be: .. parsed-literal:: 鈹屸攢鈹鈹鈹鈹鈹鈹鈹 q_0: 鈹 Ry(洗) 鈹 鈹斺攢鈹鈹鈹攢鈹鈹鈹 q_1: 鈹鈹鈹鈹鈻犫攢鈹鈹鈹 .. math:: \newcommand{\th}{\frac{\theta}{2}} CRY(\theta)\ q_1, q_0 = |0\rangle\langle 0| \otimes I + |1\rangle\langle 1| \otimes RY(\theta) = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & \cos\left(\th\right) & -\sin\left(\th\right) \\ 0 & 0 & \sin\left(\th\right) & \cos\left(\th\right) \end{pmatrix} """ def __init__( self, theta: ParameterValueType, label: Optional[str] = None, ctrl_state: Optional[Union[str, int]] = None, ): """Create new CRY gate.""" super().__init__( "cry", 2, [theta], num_ctrl_qubits=1, label=label, ctrl_state=ctrl_state, base_gate=RYGate(theta), ) def _define(self): """ gate cry(lambda) a,b { u3(lambda/2,0,0) b; cx a,b; u3(-lambda/2,0,0) b; cx a,b; } """ # pylint: disable=cyclic-import from qiskit.circuit.quantumcircuit import QuantumCircuit from .x import CXGate # q_0: 鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈻犫攢鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈻犫攢鈹 # 鈹屸攢鈹鈹鈹鈹鈹鈹鈹鈹鈹愨攲鈹鈹粹攢鈹愨攲鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹愨攲鈹鈹粹攢鈹 # q_1: 鈹 Ry(位/2) 鈹溾敜 X 鈹溾敜 Ry(位/2) 鈹溾敜 X 鈹 # 鈹斺攢鈹鈹鈹鈹鈹鈹鈹鈹鈹樷敂鈹鈹鈹鈹樷敂鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹樷敂鈹鈹鈹鈹 q = QuantumRegister(2, "q") qc = QuantumCircuit(q, name=self.name) rules = [ (RYGate(self.params[0] / 2), [q[1]], []), (CXGate(), [q[0], q[1]], []), (RYGate(-self.params[0] / 2), [q[1]], []), (CXGate(), [q[0], q[1]], []), ] for instr, qargs, cargs in rules: qc._append(instr, qargs, cargs) self.definition = qc
[documentos] def inverse(self): """Return inverse CRY gate (i.e. with the negative rotation angle).""" return CRYGate(-self.params[0], ctrl_state=self.ctrl_state)
def __array__(self, dtype=None): """Return a numpy.array for the CRY gate.""" half_theta = float(self.params[0]) / 2 cos = math.cos(half_theta) sin = math.sin(half_theta) if self.ctrl_state: return numpy.array( [[1, 0, 0, 0], [0, cos, 0, -sin], [0, 0, 1, 0], [0, sin, 0, cos]], dtype=dtype ) else: return numpy.array( [[cos, 0, -sin, 0], [0, 1, 0, 0], [sin, 0, cos, 0], [0, 0, 0, 1]], dtype=dtype )