mirror of https://github.com/Qiskit/qiskit.git
379 lines
13 KiB
Python
379 lines
13 KiB
Python
# This code is part of Qiskit.
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#
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# (C) Copyright IBM 2017, 2019.
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#
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# This code is licensed under the Apache License, Version 2.0. You may
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# obtain a copy of this license in the LICENSE.txt file in the root directory
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# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
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#
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# Any modifications or derivative works of this code must retain this
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# copyright notice, and modified files need to carry a notice indicating
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# that they have been altered from the originals.
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"""Tests for PTM quantum channel representation class."""
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import copy
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import unittest
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import numpy as np
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from numpy.testing import assert_allclose
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from qiskit import QiskitError
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from qiskit.quantum_info.states import DensityMatrix
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from qiskit.quantum_info.operators.channel import PTM
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from .channel_test_case import ChannelTestCase
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class TestPTM(ChannelTestCase):
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"""Tests for PTM channel representation."""
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def test_init(self):
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"""Test initialization"""
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mat4 = np.eye(4) / 2.0
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chan = PTM(mat4)
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assert_allclose(chan.data, mat4)
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self.assertEqual(chan.dim, (2, 2))
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self.assertEqual(chan.num_qubits, 1)
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mat16 = np.eye(16) / 4
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chan = PTM(mat16)
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assert_allclose(chan.data, mat16)
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self.assertEqual(chan.dim, (4, 4))
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self.assertEqual(chan.num_qubits, 2)
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# Wrong input or output dims should raise exception
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self.assertRaises(QiskitError, PTM, mat16, input_dims=2, output_dims=4)
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# Non multi-qubit dimensions should raise exception
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self.assertRaises(QiskitError, PTM, np.eye(6) / 2, input_dims=3, output_dims=2)
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def test_circuit_init(self):
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"""Test initialization from a circuit."""
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circuit, target = self.simple_circuit_no_measure()
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op = PTM(circuit)
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target = PTM(target)
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self.assertEqual(op, target)
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def test_circuit_init_except(self):
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"""Test initialization from circuit with measure raises exception."""
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circuit = self.simple_circuit_with_measure()
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self.assertRaises(QiskitError, PTM, circuit)
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def test_equal(self):
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"""Test __eq__ method"""
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mat = self.rand_matrix(4, 4, real=True)
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self.assertEqual(PTM(mat), PTM(mat))
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def test_copy(self):
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"""Test copy method"""
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mat = np.eye(4)
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with self.subTest("Deep copy"):
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orig = PTM(mat)
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cpy = orig.copy()
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cpy._data[0, 0] = 0.0
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self.assertFalse(cpy == orig)
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with self.subTest("Shallow copy"):
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orig = PTM(mat)
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clone = copy.copy(orig)
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clone._data[0, 0] = 0.0
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self.assertTrue(clone == orig)
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def test_clone(self):
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"""Test clone method"""
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mat = np.eye(4)
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orig = PTM(mat)
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clone = copy.copy(orig)
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clone._data[0, 0] = 0.0
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self.assertTrue(clone == orig)
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def test_is_cptp(self):
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"""Test is_cptp method."""
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self.assertTrue(PTM(self.depol_ptm(0.25)).is_cptp())
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# Non-CPTP should return false
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self.assertFalse(PTM(1.25 * self.ptmI - 0.25 * self.depol_ptm(1)).is_cptp())
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def test_compose_except(self):
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"""Test compose different dimension exception"""
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self.assertRaises(QiskitError, PTM(np.eye(4)).compose, PTM(np.eye(16)))
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self.assertRaises(QiskitError, PTM(np.eye(4)).compose, 2)
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def test_compose(self):
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"""Test compose method."""
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# Random input test state
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rho = DensityMatrix(self.rand_rho(2))
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# UnitaryChannel evolution
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chan1 = PTM(self.ptmX)
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chan2 = PTM(self.ptmY)
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chan = chan1.compose(chan2)
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rho_targ = rho.evolve(PTM(self.ptmZ))
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self.assertEqual(rho.evolve(chan), rho_targ)
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# 50% depolarizing channel
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chan1 = PTM(self.depol_ptm(0.5))
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chan = chan1.compose(chan1)
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rho_targ = rho.evolve(PTM(self.depol_ptm(0.75)))
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self.assertEqual(rho.evolve(chan), rho_targ)
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# Compose random
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ptm1 = self.rand_matrix(4, 4, real=True)
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ptm2 = self.rand_matrix(4, 4, real=True)
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chan1 = PTM(ptm1, input_dims=2, output_dims=2)
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chan2 = PTM(ptm2, input_dims=2, output_dims=2)
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rho_targ = rho.evolve(chan1).evolve(chan2)
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chan = chan1.compose(chan2)
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self.assertEqual(chan.dim, (2, 2))
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self.assertEqual(rho.evolve(chan), rho_targ)
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chan = chan1 & chan2
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self.assertEqual(chan.dim, (2, 2))
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self.assertEqual(rho.evolve(chan), rho_targ)
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def test_dot(self):
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"""Test dot method."""
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# Random input test state
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rho = DensityMatrix(self.rand_rho(2))
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# UnitaryChannel evolution
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chan1 = PTM(self.ptmX)
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chan2 = PTM(self.ptmY)
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rho_targ = rho.evolve(PTM(self.ptmZ))
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self.assertEqual(rho.evolve(chan2.dot(chan1)), rho_targ)
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self.assertEqual(rho.evolve(chan2 @ chan1), rho_targ)
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# Compose random
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ptm1 = self.rand_matrix(4, 4, real=True)
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ptm2 = self.rand_matrix(4, 4, real=True)
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chan1 = PTM(ptm1, input_dims=2, output_dims=2)
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chan2 = PTM(ptm2, input_dims=2, output_dims=2)
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rho_targ = rho.evolve(chan1).evolve(chan2)
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self.assertEqual(rho.evolve(chan2.dot(chan1)), rho_targ)
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self.assertEqual(rho.evolve(chan2 @ chan1), rho_targ)
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def test_compose_front(self):
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"""Test deprecated front compose method."""
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# Random input test state
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rho = DensityMatrix(self.rand_rho(2))
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# UnitaryChannel evolution
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chan1 = PTM(self.ptmX)
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chan2 = PTM(self.ptmY)
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chan = chan2.compose(chan1, front=True)
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rho_targ = rho.evolve(PTM(self.ptmZ))
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self.assertEqual(rho.evolve(chan), rho_targ)
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# Compose random
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ptm1 = self.rand_matrix(4, 4, real=True)
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ptm2 = self.rand_matrix(4, 4, real=True)
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chan1 = PTM(ptm1, input_dims=2, output_dims=2)
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chan2 = PTM(ptm2, input_dims=2, output_dims=2)
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rho_targ = rho.evolve(chan1).evolve(chan2)
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chan = chan2.compose(chan1, front=True)
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self.assertEqual(chan.dim, (2, 2))
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self.assertEqual(rho.evolve(chan), rho_targ)
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def test_expand(self):
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"""Test expand method."""
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rho0, rho1 = np.diag([1, 0]), np.diag([0, 1])
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rho_init = DensityMatrix(np.kron(rho0, rho0))
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chan1 = PTM(self.ptmI)
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chan2 = PTM(self.ptmX)
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# X \otimes I
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chan = chan1.expand(chan2)
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rho_targ = DensityMatrix(np.kron(rho1, rho0))
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self.assertEqual(chan.dim, (4, 4))
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self.assertEqual(rho_init.evolve(chan), rho_targ)
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# I \otimes X
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chan = chan2.expand(chan1)
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rho_targ = DensityMatrix(np.kron(rho0, rho1))
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self.assertEqual(chan.dim, (4, 4))
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self.assertEqual(rho_init.evolve(chan), rho_targ)
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# Completely depolarizing
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chan_dep = PTM(self.depol_ptm(1))
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chan = chan_dep.expand(chan_dep)
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rho_targ = DensityMatrix(np.diag([1, 1, 1, 1]) / 4)
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self.assertEqual(chan.dim, (4, 4))
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self.assertEqual(rho_init.evolve(chan), rho_targ)
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def test_tensor(self):
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"""Test tensor method."""
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rho0, rho1 = np.diag([1, 0]), np.diag([0, 1])
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rho_init = DensityMatrix(np.kron(rho0, rho0))
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chan1 = PTM(self.ptmI)
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chan2 = PTM(self.ptmX)
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# X \otimes I
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chan = chan2.tensor(chan1)
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rho_targ = DensityMatrix(np.kron(rho1, rho0))
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self.assertEqual(chan.dim, (4, 4))
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self.assertEqual(rho_init.evolve(chan), rho_targ)
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# I \otimes X
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chan = chan1.tensor(chan2)
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rho_targ = DensityMatrix(np.kron(rho0, rho1))
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self.assertEqual(chan.dim, (4, 4))
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self.assertEqual(rho_init.evolve(chan), rho_targ)
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# Completely depolarizing
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chan_dep = PTM(self.depol_ptm(1))
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chan = chan_dep.tensor(chan_dep)
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rho_targ = DensityMatrix(np.diag([1, 1, 1, 1]) / 4)
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self.assertEqual(chan.dim, (4, 4))
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self.assertEqual(rho_init.evolve(chan), rho_targ)
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def test_power(self):
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"""Test power method."""
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# 10% depolarizing channel
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p_id = 0.9
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depol = PTM(self.depol_ptm(1 - p_id))
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# Compose 3 times
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p_id3 = p_id**3
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chan3 = depol.power(3)
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targ3 = PTM(self.depol_ptm(1 - p_id3))
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self.assertEqual(chan3, targ3)
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def test_add(self):
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"""Test add method."""
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mat1 = 0.5 * self.ptmI
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mat2 = 0.5 * self.depol_ptm(1)
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chan1 = PTM(mat1)
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chan2 = PTM(mat2)
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targ = PTM(mat1 + mat2)
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self.assertEqual(chan1._add(chan2), targ)
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self.assertEqual(chan1 + chan2, targ)
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targ = PTM(mat1 - mat2)
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self.assertEqual(chan1 - chan2, targ)
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def test_add_qargs(self):
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"""Test add method with qargs."""
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mat = self.rand_matrix(8**2, 8**2)
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mat0 = self.rand_matrix(4, 4)
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mat1 = self.rand_matrix(4, 4)
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op = PTM(mat)
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op0 = PTM(mat0)
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op1 = PTM(mat1)
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op01 = op1.tensor(op0)
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eye = PTM(self.ptmI)
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with self.subTest(msg="qargs=[0]"):
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value = op + op0([0])
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target = op + eye.tensor(eye).tensor(op0)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[1]"):
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value = op + op0([1])
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target = op + eye.tensor(op0).tensor(eye)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[2]"):
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value = op + op0([2])
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target = op + op0.tensor(eye).tensor(eye)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[0, 1]"):
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value = op + op01([0, 1])
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target = op + eye.tensor(op1).tensor(op0)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[1, 0]"):
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value = op + op01([1, 0])
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target = op + eye.tensor(op0).tensor(op1)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[0, 2]"):
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value = op + op01([0, 2])
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target = op + op1.tensor(eye).tensor(op0)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[2, 0]"):
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value = op + op01([2, 0])
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target = op + op0.tensor(eye).tensor(op1)
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self.assertEqual(value, target)
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def test_sub_qargs(self):
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"""Test subtract method with qargs."""
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mat = self.rand_matrix(8**2, 8**2)
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mat0 = self.rand_matrix(4, 4)
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mat1 = self.rand_matrix(4, 4)
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op = PTM(mat)
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op0 = PTM(mat0)
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op1 = PTM(mat1)
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op01 = op1.tensor(op0)
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eye = PTM(self.ptmI)
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with self.subTest(msg="qargs=[0]"):
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value = op - op0([0])
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target = op - eye.tensor(eye).tensor(op0)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[1]"):
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value = op - op0([1])
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target = op - eye.tensor(op0).tensor(eye)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[2]"):
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value = op - op0([2])
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target = op - op0.tensor(eye).tensor(eye)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[0, 1]"):
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value = op - op01([0, 1])
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target = op - eye.tensor(op1).tensor(op0)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[1, 0]"):
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value = op - op01([1, 0])
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target = op - eye.tensor(op0).tensor(op1)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[0, 2]"):
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value = op - op01([0, 2])
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target = op - op1.tensor(eye).tensor(op0)
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self.assertEqual(value, target)
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with self.subTest(msg="qargs=[2, 0]"):
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value = op - op01([2, 0])
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target = op - op0.tensor(eye).tensor(op1)
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self.assertEqual(value, target)
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def test_add_except(self):
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"""Test add method raises exceptions."""
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chan1 = PTM(self.ptmI)
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chan2 = PTM(np.eye(16))
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self.assertRaises(QiskitError, chan1._add, chan2)
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self.assertRaises(QiskitError, chan1._add, 5)
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def test_multiply(self):
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"""Test multiply method."""
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chan = PTM(self.ptmI)
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val = 0.5
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targ = PTM(val * self.ptmI)
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self.assertEqual(chan._multiply(val), targ)
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self.assertEqual(val * chan, targ)
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targ = PTM(self.ptmI * val)
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self.assertEqual(chan * val, targ)
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def test_multiply_except(self):
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"""Test multiply method raises exceptions."""
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chan = PTM(self.ptmI)
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self.assertRaises(QiskitError, chan._multiply, "s")
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self.assertRaises(QiskitError, chan.__rmul__, "s")
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self.assertRaises(QiskitError, chan._multiply, chan)
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self.assertRaises(QiskitError, chan.__rmul__, chan)
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def test_negate(self):
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"""Test negate method"""
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chan = PTM(self.ptmI)
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targ = PTM(-self.ptmI)
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self.assertEqual(-chan, targ)
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if __name__ == "__main__":
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unittest.main()
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