def test_qfi_simple(self, method):
"""Test if the quantum fisher information calculation is correct for a simple test case.
QFI = [[1, 0], [0, 1]] - [[0, 0], [0, cos^2(a)]]
"""
# create the circuit
a, b = Parameter("a"), Parameter("b")
qc = QuantumCircuit(1)
qc.h(0)
qc.rz(a, 0)
qc.rx(b, 0)
# convert the circuit to a QFI object
op = CircuitStateFn(qc)
qfi = QFI(qfi_method=method).convert(operator=op)
# test for different values
values_dict = [{
a: np.pi / 4,
b: 0.1
}, {
a: np.pi,
b: 0.1
}, {
a: np.pi / 2,
b: 0.1
}]
correct_values = [[[1, 0], [0, 0.5]], [[1, 0], [0, 0]], [[1, 0],
[0, 1]]]
for i, value_dict in enumerate(values_dict):
actual = qfi.assign_parameters(value_dict).eval()
np.testing.assert_array_almost_equal(actual,
correct_values[i],
decimal=1)
def test_qfi(self, method):
"""Test if the quantum fisher information calculation is correct
QFI = [[1, 0], [0, 1]] - [[0, 0], [0, cos^2(a)]]
"""
a = Parameter('a')
b = Parameter('b')
params = [a, b]
q = QuantumRegister(1)
qc = QuantumCircuit(q)
qc.h(q)
qc.rz(params[0], q[0])
qc.rx(params[1], q[0])
op = CircuitStateFn(primitive=qc, coeff=1.)
qfi = QFI(qfi_method=method).convert(operator=op, params=params)
values_dict = [{
params[0]: np.pi / 4,
params[1]: 0.1
}, {
params[0]: np.pi,
params[1]: 0.1
}, {
params[0]: np.pi / 2,
params[1]: 0.1
}]
correct_values = [[[1, 0], [0, 0.5]], [[1, 0], [0, 0]], [[1, 0],
[0, 1]]]
for i, value_dict in enumerate(values_dict):
np.testing.assert_array_almost_equal(
qfi.assign_parameters(value_dict).eval(),
correct_values[i],
decimal=1)