def test_ffft_inverse(size):
qubits = LineQubit.range(size)
ffft_circuit = cirq.Circuit(ffft(qubits),
strategy=cirq.InsertStrategy.EARLIEST)
ffft_circuit.append(cirq.inverse(ffft(qubits)))
ffft_matrix = ffft_circuit.unitary(qubits_that_should_be_present=qubits)
cirq.testing.assert_allclose_up_to_global_phase(ffft_matrix,
np.identity(1 << size),
atol=1e-8)
def test_ffft_text_diagram():
qubits = LineQubit.range(8)
circuit = cirq.Circuit(ffft(qubits), strategy=cirq.InsertStrategy.EARLIEST)
assert circuit.to_text_diagram(transpose=True) == """
0 1 2 3 4 5 6 7
│ │ │ │ │ │ │ │
0↦0─1↦4───2↦1─3↦5───4↦2─5↦6───6↦3─7↦7
│ │ │ │ │ │ │ │
0↦0─1↦2───2↦1─3↦3 0↦0─1↦2───2↦1─3↦3
│ │ │ │ │ │ │ │
F₀──F₀ F₀──F₀ F₀──F₀ F₀──F₀
│ │ │ │ │ │ │ │
0↦0─1↦2───2↦1─3↦3 0↦0─1↦2───2↦1─3↦3
│ │ │ │ │ │ │ │
│ ω^0_4 │ ω^1_4 │ ω^0_4 │ ω^1_4
│ │ │ │ │ │ │ │
F₀──F₀ F₀──F₀ F₀──F₀ F₀──F₀
│ │ │ │ │ │ │ │
0↦0─1↦2───2↦1─3↦3 0↦0─1↦2───2↦1─3↦3
│ │ │ │ │ │ │ │
0↦0─1↦2───2↦4─3↦6───4↦1─5↦3───6↦5─7↦7
│ │ │ │ │ │ │ │
│ ω^0_8 │ ω^1_8 │ ω^2_8 │ ω^3_8
│ │ │ │ │ │ │ │
F₀──F₀ F₀──F₀ F₀──F₀ F₀──F₀
│ │ │ │ │ │ │ │
0↦0─1↦4───2↦1─3↦5───4↦2─5↦6───6↦3─7↦7
│ │ │ │ │ │ │ │
""".strip()
def test_ffft_multi_fermionic_mode(n, initial):
initial_state = _multi_fermionic_mode_base_state(n, *initial)
expected_state = _fourier_transform_multi_fermionic_mode(n, *initial)
qubits = LineQubit.range(n)
circuit = cirq.Circuit(ffft(qubits), strategy=cirq.InsertStrategy.EARLIEST)
state = circuit.final_wavefunction(initial_state,
qubits_that_should_be_present=qubits)
assert np.allclose(state, expected_state, rtol=0.0)
def test_ffft_single_fermionic_modes(amplitudes):
initial_state = _single_fermionic_modes_state(amplitudes)
expected_state = _single_fermionic_modes_state(
_fourier_transform_single_fermionic_modes(amplitudes))
qubits = LineQubit.range(len(amplitudes))
circuit = cirq.Circuit(ffft(qubits), strategy=cirq.InsertStrategy.EARLIEST)
state = circuit.final_wavefunction(initial_state,
qubits_that_should_be_present=qubits)
assert np.allclose(state, expected_state, rtol=0.0)
def test_ffft_multi_fermionic_mode_non_power_of_2(n, initial):
initial_state = _multi_fermionic_mode_base_state(n, *initial)
expected_state = _fourier_transform_multi_fermionic_mode(n, *initial)
qubits = LineQubit.range(n)
circuit = cirq.Circuit(ffft(qubits), strategy=cirq.InsertStrategy.EARLIEST)
state = circuit.final_wavefunction(initial_state,
qubits_that_should_be_present=qubits)
cirq.testing.assert_allclose_up_to_global_phase(state,
expected_state,
atol=1e-8)
def test_ffft_single_fermionic_modes_non_power_of_2(amplitudes):
initial_state = _single_fermionic_modes_state(amplitudes)
expected_state = _single_fermionic_modes_state(
_fourier_transform_single_fermionic_modes(amplitudes))
qubits = LineQubit.range(len(amplitudes))
circuit = cirq.Circuit(ffft(qubits), strategy=cirq.InsertStrategy.EARLIEST)
state = circuit.final_wavefunction(initial_state,
qubits_that_should_be_present=qubits)
cirq.testing.assert_allclose_up_to_global_phase(state,
expected_state,
atol=1e-8)
def test_ffft_equal_to_bogoliubov(size):
def fourier_transform_matrix():
root_of_unity = np.exp(-2j * np.pi / size)
return np.array([[root_of_unity**(j * k) for k in range(size)]
for j in range(size)]) / np.sqrt(size)
qubits = LineQubit.range(size)
ffft_circuit = cirq.Circuit(ffft(qubits),
strategy=cirq.InsertStrategy.EARLIEST)
ffft_matrix = ffft_circuit.unitary(qubits_that_should_be_present=qubits)
bogoliubov_circuit = cirq.Circuit(bogoliubov_transform(
qubits, fourier_transform_matrix()),
strategy=cirq.InsertStrategy.EARLIEST)
bogoliubov_matrix = bogoliubov_circuit.unitary(
qubits_that_should_be_present=qubits)
cirq.testing.assert_allclose_up_to_global_phase(ffft_matrix,
bogoliubov_matrix,
atol=1e-8)
def test_ffft_fails_without_qubits():
with pytest.raises(ValueError):
ffft([])
def test_ffft_fails_for_odd_size():
with pytest.raises(ValueError):
ffft(LineQubit.range(3))
