C贸digo fuente para qiskit.extensions.unitary

# 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
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Arbitrary unitary circuit instruction.

import numpy

from qiskit.circuit import Gate, ControlledGate
from qiskit.circuit import QuantumCircuit
from qiskit.circuit import QuantumRegister, Qubit
from qiskit.circuit.exceptions import CircuitError
from qiskit.circuit._utils import _compute_control_matrix
from qiskit.circuit.library.standard_gates import U3Gate
from qiskit.extensions.quantum_initializer import isometry
from qiskit.quantum_info.operators.predicates import matrix_equal
from qiskit.quantum_info.operators.predicates import is_unitary_matrix
from qiskit.quantum_info.synthesis.one_qubit_decompose import OneQubitEulerDecomposer
from qiskit.quantum_info.synthesis.two_qubit_decompose import two_qubit_cnot_decompose
from qiskit.extensions.exceptions import ExtensionError

_DECOMPOSER1Q = OneQubitEulerDecomposer("U3")

[documentos]class UnitaryGate(Gate): """Class quantum gates specified by a unitary matrix. Example: We can create a unitary gate from a unitary matrix then add it to a quantum circuit. The matrix can also be directly applied to the quantum circuit, see :meth:`.QuantumCircuit.unitary`. .. code-block:: python from qiskit import QuantumCircuit from qiskit.extensions import UnitaryGate matrix = [[0, 0, 0, 1], [0, 0, 1, 0], [1, 0, 0, 0], [0, 1, 0, 0]] gate = UnitaryGate(matrix) circuit = QuantumCircuit(2) circuit.append(gate, [0, 1]) """ def __init__(self, data, label=None): """Create a gate from a numeric unitary matrix. Args: data (matrix or Operator): unitary operator. label (str): unitary name for backend [Default: None]. Raises: ExtensionError: if input data is not an N-qubit unitary operator. """ if hasattr(data, "to_matrix"): # If input is Gate subclass or some other class object that has # a to_matrix method this will call that method. data = data.to_matrix() elif hasattr(data, "to_operator"): # If input is a BaseOperator subclass this attempts to convert # the object to an Operator so that we can extract the underlying # numpy matrix from `Operator.data`. data = data.to_operator().data # Convert to numpy array in case not already an array data = numpy.array(data, dtype=complex) # Check input is unitary if not is_unitary_matrix(data): raise ExtensionError("Input matrix is not unitary.") # Check input is N-qubit matrix input_dim, output_dim = data.shape num_qubits = int(numpy.log2(input_dim)) if input_dim != output_dim or 2**num_qubits != input_dim: raise ExtensionError("Input matrix is not an N-qubit operator.") # Store instruction params super().__init__("unitary", num_qubits, [data], label=label) def __eq__(self, other): if not isinstance(other, UnitaryGate): return False if self.label != other.label: return False # Should we match unitaries as equal if they are equal # up to global phase? return matrix_equal(self.params[0], other.params[0], ignore_phase=True) def __array__(self, dtype=None): """Return matrix for the unitary.""" # pylint: disable=unused-argument return self.params[0]
[documentos] def inverse(self): """Return the adjoint of the unitary.""" return self.adjoint()
[documentos] def conjugate(self): """Return the conjugate of the unitary.""" return UnitaryGate(numpy.conj(self.to_matrix()))
[documentos] def adjoint(self): """Return the adjoint of the unitary.""" return self.transpose().conjugate()
[documentos] def transpose(self): """Return the transpose of the unitary.""" return UnitaryGate(numpy.transpose(self.to_matrix()))
def _define(self): """Calculate a subcircuit that implements this unitary.""" if self.num_qubits == 1: q = QuantumRegister(1, "q") qc = QuantumCircuit(q, name=self.name) theta, phi, lam, global_phase = _DECOMPOSER1Q.angles_and_phase(self.to_matrix()) qc._append(U3Gate(theta, phi, lam), [q[0]], []) qc.global_phase = global_phase self.definition = qc elif self.num_qubits == 2: self.definition = two_qubit_cnot_decompose(self.to_matrix()) else: from qiskit.quantum_info.synthesis.qsd import ( # pylint: disable=cyclic-import qs_decomposition, ) self.definition = qs_decomposition(self.to_matrix())
[documentos] def control(self, num_ctrl_qubits=1, label=None, ctrl_state=None): """Return controlled version of gate Args: num_ctrl_qubits (int): number of controls to add to gate (default=1) label (str): optional gate label ctrl_state (int or str or None): The control state in decimal or as a bit string (e.g. '1011'). If None, use 2**num_ctrl_qubits-1. Returns: UnitaryGate: controlled version of gate. Raises: QiskitError: Invalid ctrl_state. ExtensionError: Non-unitary controlled unitary. """ mat = self.to_matrix() cmat = _compute_control_matrix(mat, num_ctrl_qubits, ctrl_state=None) iso = isometry.Isometry(cmat, 0, 0) return ControlledGate( "c-unitary", num_qubits=self.num_qubits + num_ctrl_qubits, params=[mat], label=label, num_ctrl_qubits=num_ctrl_qubits, definition=iso.definition, ctrl_state=ctrl_state, base_gate=self.copy(), )
def _qasm2_decomposition(self): """Return an unparameterized version of ourselves, so the OQ2 exporter doesn't choke on the non-standard things in our `params` field.""" out = self.definition.to_gate() out.name = self.name return out
[documentos] def validate_parameter(self, parameter): """Unitary gate parameter has to be an ndarray.""" if isinstance(parameter, numpy.ndarray): return parameter else: raise CircuitError(f"invalid param type {type(parameter)} in gate {self.name}")
def unitary(self, obj, qubits, label=None): """Apply unitary gate specified by ``obj`` to ``qubits``. Args: obj (matrix or Operator): unitary operator. qubits (Union[int, Tuple[int]]): The circuit qubits to apply the transformation to. label (str): unitary name for backend [Default: None]. Returns: QuantumCircuit: The quantum circuit. Raises: ExtensionError: if input data is not an N-qubit unitary operator. Example: Apply a gate specified by a unitary matrix to a quantum circuit .. code-block:: python from qiskit import QuantumCircuit matrix = [[0, 0, 0, 1], [0, 0, 1, 0], [1, 0, 0, 0], [0, 1, 0, 0]] circuit = QuantumCircuit(2) circuit.unitary(matrix, [0, 1]) """ gate = UnitaryGate(obj, label=label) if isinstance(qubits, QuantumRegister): qubits = qubits[:] # for single qubit unitary gate, allow an 'int' or a 'list of ints' as qubits. if gate.num_qubits == 1: if isinstance(qubits, (int, Qubit)) or len(qubits) > 1: qubits = [qubits] return self.append(gate, qubits, []) QuantumCircuit.unitary = unitary