def test_requirement_1to2():
req = IOSpec(State({(1, 2): 1.0}), State({(0, 3): 0.5, (2, 1): 1.0}))
gen = (i for i in req.paths)
assert next(gen) == ((1, 2), (0, 3), 0.5)
assert next(gen) == ((1, 2), (2, 1), 1.0)
with pytest.raises(StopIteration):
next(gen)
def test_gradients_onephoton():
ket_in = np.zeros((5, 5, 5, 5), dtype=np.complex128)
ket_in[1, 1, 1, 0] = 1.0
test_prog = sf.Program(4) # 4 modes
with test_prog.context as q:
sf.ops.Ket(ket_in) | (q[0], q[1], q[2], q[3])
sf.ops.BSgate(0.1804, 0.0578) | (q[0], q[1])
sf.ops.BSgate(0.06406, 1.5165) | (q[2], q[3])
sf.ops.BSgate(1.473, 0.1176) | (q[1], q[2])
sf.ops.BSgate(0.263, -0.2517) | (q[0], q[1])
sf.ops.BSgate(0.3323, 1.9946) | (q[2], q[3])
sf.ops.BSgate(0.311, -0.3231) | (q[1], q[2])
sf.ops.BSgate(0.4348, 0.0798) | (q[0], q[1])
sf.ops.BSgate(0.0368, 0.6157) | (q[2], q[3])
prog_unitary = sf.Program(4)
prog_unitary.circuit = test_prog.circuit[1:]
prog_compiled = prog_unitary.compile(compiler="gaussian_unitary")
S = prog_compiled.circuit[0].op.p[0]
U1 = S[:4, :4] + 1j * S[4:, :4]
ket_in = np.zeros((5, 5, 5, 5), dtype=np.complex128)
ket_in[1, 2, 1, 0] = 1.0
test_prog = sf.Program(4) # 4 modes
with test_prog.context as q:
sf.ops.Ket(ket_in) | (q[0], q[1], q[2], q[3])
sf.ops.BSgate(0.1804, 0.0568) | (q[0], q[1])
sf.ops.BSgate(0.06306, 1.5165) | (q[2], q[3])
sf.ops.BSgate(1.472, 0.1176) | (q[1], q[2])
sf.ops.BSgate(0.263, -0.2507) | (q[0], q[1])
sf.ops.BSgate(0.3333, 1.9946) | (q[2], q[3])
sf.ops.BSgate(0.312, -0.3231) | (q[1], q[2])
sf.ops.BSgate(0.4358, 0.0788) | (q[0], q[1])
sf.ops.BSgate(0.0358, 0.6157) | (q[2], q[3])
prog_unitary = sf.Program(4)
prog_unitary.circuit = test_prog.circuit[1:]
prog_compiled = prog_unitary.compile(compiler="gaussian_unitary")
S = prog_compiled.circuit[0].op.p[0]
U2 = S[:4, :4] + 1j * S[4:, :4]
dU = U2 - U1
s_in = State({(1, 1, 1, 0): 1.0})
s_out = State({(1, 0, 1, 1): 1.0})
io = IOSpec(input_state=s_in, output_state=s_out)
tree1 = Tree(io=io, covariance_matrix=U1)
tree2 = Tree(io=io, covariance_matrix=U1 + dU)
amp1, grad1 = tree1.amplitude()
amp2, grad2 = tree2.amplitude()
print(f'tree builds input: {io.building_input}')
print(grad1)
print(amp2, amp1 + np.sum(grad1 * dU))
print(amp2 - amp1, np.sum(grad1 * dU))
assert np.isclose(amp2 - amp1, np.sum(grad1 * dU))
assert np.isclose(amp1 - amp2, -np.sum(grad2 * dU))
def test_amplitude_2to2amplitudes():
ket_in = np.zeros((5, 5, 5, 5), dtype=np.complex128)
ket_in[1, 2, 1, 0] = np.sqrt(1 / 3)
ket_in[1, 0, 0, 3] = 1j * np.sqrt(2 / 3)
test_prog = sf.Program(4) # 4 modes
with test_prog.context as q:
sf.ops.Ket(ket_in) | (q[0], q[1], q[2], q[3])
sf.ops.BSgate(0.1804, 0.0578) | (q[0], q[1])
sf.ops.BSgate(0.06406, 1.5165) | (q[2], q[3])
sf.ops.BSgate(1.473, 0.1176) | (q[1], q[2])
sf.ops.BSgate(0.263, -0.2517) | (q[0], q[1])
sf.ops.BSgate(0.3323, 1.9946) | (q[2], q[3])
sf.ops.BSgate(0.311, -0.3231) | (q[1], q[2])
sf.ops.BSgate(0.4348, 0.0798) | (q[0], q[1])
sf.ops.BSgate(0.0368, 0.6157) | (q[2], q[3])
eng = sf.Engine(backend="fock", backend_options={"cutoff_dim": 5})
results = eng.run(test_prog)
ket = results.state.ket()
# getting the unitary of the interferometer
prog_unitary = sf.Program(4)
prog_unitary.circuit = test_prog.circuit[1:]
prog_compiled = prog_unitary.compile(compiler="gaussian_unitary")
S = prog_compiled.circuit[0].op.p[0]
U = S[:4, :4] + 1j * S[4:, :4]
# sqrt(1/3)|1,2,1,0> + 1j*sqrt(2/3)|1,0,0,3> ---> np.sqrt(1/7)|2,0,1,1> - 1j*np.sqrt(6/7)|4,0,0,0>
s_in = State({
(1, 2, 1, 0): np.sqrt(1 / 3),
(1, 0, 0, 3): 1j * np.sqrt(2 / 3)
})
s_out = State({
(2, 0, 1, 1): np.sqrt(1 / 7),
(4, 0, 0, 0): -1j * np.sqrt(6 / 7)
})
io = IOSpec(input_state=s_in, output_state=s_out)
tree = Tree(io=io, covariance_matrix=U)
assert np.isclose(
np.sqrt(1 / 7) * ket[2, 0, 1, 1] +
1j * np.sqrt(6 / 7) * ket[4, 0, 0, 0],
tree.amplitude()[0]) # note: complex conj
def test_amplitude_manyphotons():
test_prog = sf.Program(4) # 4 modes
with test_prog.context as q:
sf.ops.Fock(1) | q[0]
sf.ops.Fock(2) | q[1]
sf.ops.Fock(1) | q[2]
# sf.ops.Fock(0) | q[3]
sf.ops.BSgate(0.7804, 0.8578) | (q[0], q[1])
sf.ops.BSgate(0.06406, 0.5165) | (q[2], q[3])
sf.ops.BSgate(1.473, 0.1176) | (q[1], q[2])
sf.ops.BSgate(0.563, 0.1517) | (q[0], q[1])
sf.ops.BSgate(0.1323, 1.9946) | (q[2], q[3])
sf.ops.BSgate(0.311, -0.3231) | (q[1], q[2])
sf.ops.BSgate(0.4348, 0.0798) | (q[0], q[1])
sf.ops.BSgate(0.4368, 0.6157) | (q[2], q[3])
eng = sf.Engine(backend="fock", backend_options={"cutoff_dim": 5})
results = eng.run(test_prog)
probs = results.state.all_fock_probs()
# getting the unitary of the interferometer
prog_unitary = sf.Program(4)
prog_unitary.circuit = test_prog.circuit[3:]
prog_compiled = prog_unitary.compile(compiler="gaussian_unitary")
S = prog_compiled.circuit[0].op.p[0]
U = S[:4, :4] + 1j * S[4:, :4]
# |1,2,1,0> --> |4,0,0,0>
# |1,0,0,3> --> |2,2,0,0>
s_in = State({(1, 2, 1, 0): 1.0})
s_out1 = State({(4, 0, 0, 0): 1.0})
s_out2 = State({(2, 2, 0, 0): 1.0})
io1 = IOSpec(input_state=s_in, output_state=s_out1)
io2 = IOSpec(input_state=s_in, output_state=s_out2)
tree1 = Tree(io=io1, covariance_matrix=U)
tree2 = Tree(io=io2, covariance_matrix=U)
assert np.isclose(probs[4, 0, 0, 0], abs(tree1.amplitude()[0])**2)
assert np.isclose(probs[2, 2, 0, 0], abs(tree2.amplitude()[0])**2)
def test_state_normalization():
state = State()
state[(1, 2, 3)] = 0.5
state[(1, 3, 9)] = 0.5
state.normalize()
assert np.isclose(sum(abs(s)**2 for s in state.values()), 1)
def test_gradients2to1():
ket_in = np.zeros((5, 5, 5, 5), dtype=np.complex128)
ket_in[1, 2, 1, 0] = np.sqrt(1 / 3)
ket_in[1, 0, 0, 3] = 1j * np.sqrt(2 / 3)
test_prog = sf.Program(4) # 4 modes
with test_prog.context as q:
sf.ops.Ket(ket_in) | (q[0], q[1], q[2], q[3])
sf.ops.BSgate(0.1804, 0.0578) | (q[0], q[1])
sf.ops.BSgate(0.06406, 1.5165) | (q[2], q[3])
sf.ops.BSgate(1.473, 0.1176) | (q[1], q[2])
sf.ops.BSgate(0.263, -0.2517) | (q[0], q[1])
sf.ops.BSgate(0.3323, 1.9946) | (q[2], q[3])
sf.ops.BSgate(0.311, -0.3231) | (q[1], q[2])
sf.ops.BSgate(0.4348, 0.0798) | (q[0], q[1])
sf.ops.BSgate(0.0368, 0.6157) | (q[2], q[3])
# eng = sf.Engine(backend="fock", backend_options={"cutoff_dim": 5})
# ket_out_1 = eng.run(test_prog).state.ket()
prog_unitary = sf.Program(4)
prog_unitary.circuit = test_prog.circuit[1:]
prog_compiled = prog_unitary.compile(compiler="gaussian_unitary")
S = prog_compiled.circuit[0].op.p[0]
U1 = S[:4, :4] + 1j * S[4:, :4]
ket_in = np.zeros((5, 5, 5, 5), dtype=np.complex128)
ket_in[1, 2, 1, 0] = np.sqrt(1 / 3)
ket_in[1, 0, 0, 3] = 1j * np.sqrt(2 / 3)
test_prog = sf.Program(4) # 4 modes
with test_prog.context as q:
sf.ops.Ket(ket_in) | (q[0], q[1], q[2], q[3])
sf.ops.BSgate(0.1804, 0.0568) | (q[0], q[1])
sf.ops.BSgate(0.06306, 1.5165) | (q[2], q[3])
sf.ops.BSgate(1.462, 0.1176) | (q[1], q[2])
sf.ops.BSgate(0.263, -0.2507) | (q[0], q[1])
sf.ops.BSgate(0.3333, 1.9946) | (q[2], q[3])
sf.ops.BSgate(0.312, -0.3231) | (q[1], q[2])
sf.ops.BSgate(0.4358, 0.0788) | (q[0], q[1])
sf.ops.BSgate(0.0358, 0.6157) | (q[2], q[3])
# eng = sf.Engine(backend="fock", backend_options={"cutoff_dim": 5})
# ket_out_2 = eng.run(test_prog).state.ket()
prog_unitary = sf.Program(4)
prog_unitary.circuit = test_prog.circuit[1:]
prog_compiled = prog_unitary.compile(compiler="gaussian_unitary")
S = prog_compiled.circuit[0].op.p[0]
U2 = S[:4, :4] + 1j * S[4:, :4]
dU = U2 - U1
s_in = State({
(1, 2, 1, 0): np.sqrt(1 / 3),
(1, 0, 0, 3): 1j * np.sqrt(2 / 3)
})
s_out = State({(4, 0, 0, 0): 1.0})
io = IOSpec(input_state=s_in, output_state=s_out)
tree1 = Tree(io=io, covariance_matrix=U1)
tree2 = Tree(io=io, covariance_matrix=U1 + dU)
amp1, grad1 = tree1.amplitude()
amp2, grad2 = tree2.amplitude()
print(amp2, amp1 + np.sum(grad1 * dU))
print(np.sum(grad1 * dU), amp2 - amp1)
assert np.isclose(amp2, amp1 + np.sum(grad1 * dU))
assert np.isclose(amp1, amp2 - np.sum(grad2 * dU))