def test_merge(self, hbar, tol):
"""Test that two covariances matrices overwrite each other on merge"""
n = 3
V1 = random_covariance(n, pure=False, hbar=hbar)
V2 = random_covariance(n, pure=True, hbar=hbar)
cov1 = ops.Gaussian(V1, hbar=hbar)
cov2 = ops.Gaussian(V2, hbar=hbar)
# applying a second covariance matrix replaces the first
assert cov1.merge(cov2) == cov2
# the same is true of state preparations
assert ops.Squeezed(2).merge(cov2) == cov2
def test_interferometer(self, setup_eng, tol):
"""Test applying an interferometer"""
eng, q = setup_eng(3)
with eng:
ops.All(ops.Squeezed(0.5)) | q
init = eng.run()
ops.Interferometer(u1) | q
state = eng.run()
O = np.vstack(
[np.hstack([u1.real, -u1.imag]),
np.hstack([u1.imag, u1.real])])
assert np.allclose(state.cov(), O @ init.cov() @ O.T, atol=tol)
def test_interferometer(self, setup_eng, tol):
"""Test applying an interferometer"""
eng, p1 = setup_eng(3)
with p1.context as q:
ops.All(ops.Squeezed(0.5)) | q
init = eng.run(p1).state
p2 = sf.Program(p1)
with p2.context as q:
ops.Interferometer(u1) | q
state = eng.run(p2).state
O = np.vstack([np.hstack([u1.real, -u1.imag]), np.hstack([u1.imag, u1.real])])
assert np.allclose(state.cov(), O @ init.cov() @ O.T, atol=tol)
def test_passive_gaussian_transform(self, setup_eng, tol):
"""Test applying a passive Gaussian symplectic transform,
which is simply an interferometer"""
eng, q = setup_eng(3)
O = np.vstack(
[np.hstack([u1.real, -u1.imag]),
np.hstack([u1.imag, u1.real])])
with eng:
ops.All(ops.Squeezed(0.5)) | q
init = eng.run()
ops.GaussianTransform(O) | q
state = eng.run()
assert np.allclose(state.cov(), O @ init.cov() @ O.T, atol=tol)
def test_merge(self, hbar, tol):
"""Test that merging two Preparations only keeps the latter one."""
n = 3
V1 = random_covariance(n, pure=False, hbar=hbar)
V2 = random_covariance(n, pure=True, hbar=hbar)
r1 = np.random.randn(2 * n)
r2 = np.random.randn(2 * n)
G1 = ops.Gaussian(V1, r1)
G2 = ops.Gaussian(V2, r2)
# applying a second state preparation replaces the first
assert G1.merge(G2) is G2
# the same is true of all state preparations
S = ops.Squeezed(2)
assert S.merge(G2) is G2
assert G2.merge(S) is S
def prog():
prog = Program(4, name="test_program")
with prog.context as q:
# state preparation
ops.Vac | q[1]
ops.Squeezed(0.12) | q[2]
# one mode gates
ops.Sgate(1) | q[0]
ops.Dgate(np.abs(0.54 + 0.5j), np.angle(0.54 + 0.5j)) | q[1]
# two mode gates
ops.S2gate(0.543, -0.12) | (q[0], q[3])
# decomposition
ops.Interferometer(U) | q
# measurement
ops.MeasureX | q[0]
ops.MeasureHomodyne(0.43, select=0.32) | q[2]
ops.MeasureHomodyne(phi=0.43, select=0.32) | q[2]
return prog
