Quellcode für qiskit.circuit.library.standard_gates.r

# This code is part of Qiskit.
# (C) Copyright IBM 2017, 2019
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

"""Rotation around an axis in x-y plane."""

import math
from cmath import exp
from math import pi
from typing import Optional
import numpy
from qiskit.circuit.gate import Gate
from qiskit.circuit.quantumregister import QuantumRegister
from qiskit.circuit.parameterexpression import ParameterValueType

[Doku]class RGate(Gate): r"""Rotation θ around the cos(φ)x + sin(φ)y axis. Can be applied to a :class:`~qiskit.circuit.QuantumCircuit` with the :meth:`~qiskit.circuit.QuantumCircuit.r` method. **Circuit symbol:** .. parsed-literal:: ┌──────┐ q_0: ┤ R(ϴ) ├ └──────┘ **Matrix Representation:** .. math:: \newcommand{\th}{\frac{\theta}{2}} R(\theta, \phi) = e^{-i \th \left(\cos{\phi} x + \sin{\phi} y\right)} = \begin{pmatrix} \cos\left(\th\right) & -i e^{-i \phi} \sin\left(\th\right) \\ -i e^{i \phi} \sin\left(\th\right) & \cos\left(\th\right) \end{pmatrix} """ def __init__( self, theta: ParameterValueType, phi: ParameterValueType, label: Optional[str] = None ): """Create new r single-qubit gate.""" super().__init__("r", 1, [theta, phi], label=label) def _define(self): """ gate r(θ, φ) a {u3(θ, φ - π/2, -φ + π/2) a;} """ # pylint: disable=cyclic-import from qiskit.circuit.quantumcircuit import QuantumCircuit from .u3 import U3Gate q = QuantumRegister(1, "q") qc = QuantumCircuit(q, name=self.name) theta = self.params[0] phi = self.params[1] rules = [(U3Gate(theta, phi - pi / 2, -phi + pi / 2), [q[0]], [])] for instr, qargs, cargs in rules: qc._append(instr, qargs, cargs) self.definition = qc
[Doku] def inverse(self): """Invert this gate. r(θ, φ)^dagger = r(-θ, φ) """ return RGate(-self.params[0], self.params[1])
def __array__(self, dtype=None): """Return a numpy.array for the R gate.""" theta, phi = float(self.params[0]), float(self.params[1]) cos = math.cos(theta / 2) sin = math.sin(theta / 2) exp_m = exp(-1j * phi) exp_p = exp(1j * phi) return numpy.array([[cos, -1j * exp_m * sin], [-1j * exp_p * sin, cos]], dtype=dtype)
[Doku] def power(self, exponent: float): """Raise gate to a power.""" theta, phi = self.params return RGate(exponent * theta, phi)