def test_energy():
"""Check energy callback for state vectors and density matrices."""
from qibo import hamiltonians
ham = hamiltonians.TFIM(4, h=1.0)
energy = callbacks.Energy(ham)
matrix = np.array(ham.matrix)
state = np.random.random(16) + 1j * np.random.random(16)
target_energy = state.conj().dot(matrix.dot(state))
np.testing.assert_allclose(energy(state), target_energy)
state = np.random.random((16, 16)) + 1j * np.random.random((16, 16))
target_energy = np.trace(matrix.dot(state))
np.testing.assert_allclose(energy(state, True), target_energy)
def test_energy(backend, density_matrix):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
from qibo import hamiltonians
ham = hamiltonians.TFIM(4, h=1.0)
energy = callbacks.Energy(ham)
matrix = np.array(ham.matrix)
if density_matrix:
energy.density_matrix = True
state = np.random.random((16, 16)) + 1j * np.random.random((16, 16))
target_energy = np.trace(matrix.dot(state))
else:
state = np.random.random(16) + 1j * np.random.random(16)
target_energy = state.conj().dot(matrix.dot(state))
np.testing.assert_allclose(energy(state), target_energy)
qibo.set_backend(original_backend)
def test_energy_callback(solver, atol, dt=1e-2):
"""Test using energy callback in adiabatic evolution."""
h0 = hamiltonians.X(2)
h1 = hamiltonians.TFIM(2)
energy = callbacks.Energy(h1)
adev = models.AdiabaticEvolution(h0,
h1,
lambda t: t,
dt=dt,
callbacks=[energy],
solver=solver)
final_psi = adev(final_time=1)
target_psi = np.ones(4) / 2
calc_energy = lambda psi: psi.conj().dot(h1.matrix.numpy().dot(psi))
target_energies = [calc_energy(target_psi)]
ham = lambda t: h0 * (1 - t) + h1 * t
for n in range(int(1 / dt)):
prop = ham(n * dt).exp(dt).numpy()
target_psi = prop.dot(target_psi)
target_energies.append(calc_energy(target_psi))
assert_states_equal(final_psi, target_psi, atol=atol)
np.testing.assert_allclose(energy[:], target_energies, atol=atol)