def test_tensor(self):
"""Test tensor method."""
rho0, rho1 = np.diag([1, 0]), np.diag([0, 1])
rho_init = DensityMatrix(np.kron(rho0, rho0))
chan1 = PTM(self.ptmI)
chan2 = PTM(self.ptmX)
# X \otimes I
chan = chan2.tensor(chan1)
rho_targ = DensityMatrix(np.kron(rho1, rho0))
self.assertEqual(chan.dim, (4, 4))
self.assertEqual(rho_init.evolve(chan), rho_targ)
# I \otimes X
chan = chan1.tensor(chan2)
rho_targ = DensityMatrix(np.kron(rho0, rho1))
self.assertEqual(chan.dim, (4, 4))
self.assertEqual(rho_init.evolve(chan), rho_targ)
# Completely depolarizing
chan_dep = PTM(self.depol_ptm(1))
chan = chan_dep.tensor(chan_dep)
rho_targ = DensityMatrix(np.diag([1, 1, 1, 1]) / 4)
self.assertEqual(chan.dim, (4, 4))
self.assertEqual(rho_init.evolve(chan), rho_targ)
def test_sub_qargs(self):
"""Test subtract method with qargs."""
mat = self.rand_matrix(8**2, 8**2)
mat0 = self.rand_matrix(4, 4)
mat1 = self.rand_matrix(4, 4)
op = PTM(mat)
op0 = PTM(mat0)
op1 = PTM(mat1)
op01 = op1.tensor(op0)
eye = PTM(self.ptmI)
with self.subTest(msg='qargs=[0]'):
value = op - op0([0])
target = op - eye.tensor(eye).tensor(op0)
self.assertEqual(value, target)
with self.subTest(msg='qargs=[1]'):
value = op - op0([1])
target = op - eye.tensor(op0).tensor(eye)
self.assertEqual(value, target)
with self.subTest(msg='qargs=[2]'):
value = op - op0([2])
target = op - op0.tensor(eye).tensor(eye)
self.assertEqual(value, target)
with self.subTest(msg='qargs=[0, 1]'):
value = op - op01([0, 1])
target = op - eye.tensor(op1).tensor(op0)
self.assertEqual(value, target)
with self.subTest(msg='qargs=[1, 0]'):
value = op - op01([1, 0])
target = op - eye.tensor(op0).tensor(op1)
self.assertEqual(value, target)
with self.subTest(msg='qargs=[0, 2]'):
value = op - op01([0, 2])
target = op - op1.tensor(eye).tensor(op0)
self.assertEqual(value, target)
with self.subTest(msg='qargs=[2, 0]'):
value = op - op01([2, 0])
target = op - op0.tensor(eye).tensor(op1)
self.assertEqual(value, target)
