def measure(p, ro, idx, qc, qbits, correction_matrix):
# Circuit to measure the expectation value of any Pauli string
if idx == 0:
return 1
elif idx == 1:
qc = get_qc(qc)
p += H(qbits[0])
p += MEASURE(qbits[0], ro[0])
exe = qc.compile(p)
res = qc.run(exe)
probs = estimate_bitstring_probs(res)
probs = correct_bitstring_probs(probs, [correction_matrix])
return probs[0] - probs[1]
elif idx == 2:
qc = get_qc(qc)
p += RX(np.pi / 2, qbits[0])
p += MEASURE(qbits[0], ro[0])
exe = qc.compile(p)
res = qc.run(exe)
probs = estimate_bitstring_probs(res)
probs = correct_bitstring_probs(probs, [correction_matrix])
return probs[0] - probs[1]
elif idx == 3:
qc = get_qc(qc)
p += MEASURE(qbits[0], ro[0])
exe = qc.compile(p)
res = qc.run(exe)
probs = estimate_bitstring_probs(res)
probs = correct_bitstring_probs(probs, [correction_matrix])
return probs[0] - probs[1]
def test_readout_compensation():
np.random.seed(1234124)
p = np.random.rand(2, 2, 2, 2, 2, 2)
p /= p.sum()
aps = [np.eye(2) + .2 * (np.random.rand(2, 2) - 1) for _ in range(p.ndim)]
for ap in aps:
ap.flat[ap.flat < 0] = 0.
ap /= ap.sum()
assert np.alltrue(ap >= 0)
assert np.alltrue(p >= 0)
p_corrupted = corrupt_bitstring_probs(p, aps)
p_restored = correct_bitstring_probs(p_corrupted, aps)
assert np.allclose(p, p_restored)
results = [[0, 0, 0]] * 100 + [[0, 1, 1]] * 200
p1 = estimate_bitstring_probs(results)
assert np.isclose(p1[0, 0, 0], 1. / 3.)
assert np.isclose(p1[0, 1, 1], 2. / 3.)
assert np.isclose(p1.sum(), 1.)
zm = bitstring_probs_to_z_moments(p1)
assert np.isclose(zm[0, 0, 0], 1)
assert np.isclose(zm[1, 0, 0], 1)
assert np.isclose(zm[0, 1, 0], -1. / 3)
assert np.isclose(zm[0, 0, 1], -1. / 3)
assert np.isclose(zm[0, 1, 1], 1.)
assert np.isclose(zm[1, 1, 0], -1. / 3)
assert np.isclose(zm[1, 0, 1], -1. / 3)
assert np.isclose(zm[1, 1, 1], 1.)
