def test_planar_mps2d_contract():
code = PlanarCode(3, 3)
sample = code.new_pauli().site('Y', (2, 0), (2, 4))
prob_dist = DepolarizingErrorModel().probability_distribution(0.1)
tnc = PlanarMPSDecoder.TNC()
tn = tnc.create_tn(prob_dist, sample)
result = tt.mps2d.contract(tn)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
assert 0 <= result <= 1, 'Contracted tensor network not within bounds'
def test_planar_mps2d_contract_mask():
code = PlanarCode(3, 4)
sample = code.new_pauli().site('Y', (2, 0), (2, 4))
prob_dist = DepolarizingErrorModel().probability_distribution(0.1)
tnc = PlanarMPSDecoder.TNC()
tn = tnc.create_tn(prob_dist, sample)
rng = np.random.default_rng()
# tn_contract exact
exact_result = tt.mps2d.contract(tn)
assert isinstance(exact_result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
assert 0 <= exact_result <= 1, 'Contracted tensor network not within bounds'
print('#exact_result=', exact_result)
# tn_contract approx
approx_result = tt.mps2d.contract(tn, chi=2)
assert isinstance(approx_result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
assert 0 <= approx_result <= 1, 'Contracted tensor network not within bounds'
print('#approx_result=', approx_result, '#rtol=',
abs(approx_result - exact_result) / abs(exact_result))
assert _is_close(exact_result, approx_result, rtol=1e-4,
atol=0), 'tn_contract(chi=2) not as expected'
# tn_contract with truncate (chi, mask=0)
stp = 0 # skip truncate probability
mask = rng.choice((True, False), size=tn.shape, p=(1 - stp, stp))
result = tt.mps2d.contract(tn, chi=2, mask=mask)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
assert 0 <= result <= 1, 'Contracted tensor network not within bounds'
print('#result (chi=2, mask=0)=', result, '#rtol=',
abs(result - approx_result) / abs(approx_result))
assert approx_result == result, 'tn_contract(chi=2, mask=0) not same as approx_result'
# tn_contract with truncate (chi, mask=1)
stp = 1 # skip truncate probability
mask = rng.choice((True, False), size=tn.shape, p=(1 - stp, stp))
result = tt.mps2d.contract(tn, chi=2, mask=mask)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
assert 0 <= result <= 1, 'Contracted tensor network not within bounds'
print('#result (chi=2, mask=1)=', result, '#rtol=',
abs(result - exact_result) / abs(exact_result))
assert exact_result == result, 'tn_contract(chi=2, mask=1) not same as exact_result'
# tn_contract with truncate (chi, mask=0.5)
stp = 0.5 # skip truncate probability
mask = rng.choice((True, False), size=tn.shape, p=(1 - stp, stp))
result = tt.mps2d.contract(tn, chi=2, mask=mask)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
assert 0 <= result <= 1, 'Contracted tensor network not within bounds'
print('#result (chi=2, mask=0.5)=', result, '#rtol=',
abs(result - exact_result) / abs(exact_result))
assert exact_result != result, 'tn_contract(chi=2, mask=0.5) should not equal exact_result'
assert approx_result != result, 'tn_contract(chi=2, mask=0.5) should not equal approx_result'
assert _is_close(
exact_result, result, rtol=1e-4,
atol=0), 'tn_contract(chi=2, mask=0.5) not close to exact_result'
print('#result (chi=2, mask=0.5)=', result, '#rtol=',
abs(result - approx_result) / abs(approx_result))
assert _is_close(
approx_result, result, rtol=1e-4,
atol=0), ('tn_contract(chi=2, mask=0.5) not close to approx_result')
def test_planar_mps_functions():
prob_dist = DepolarizingErrorModel().probability_distribution(0.1)
rng = np.random.default_rng()
tnc = PlanarMPSDecoder.TNC()
# column bra, mpo and ket
bra = [
tnc.create_h_node(prob_dist, 'X', 'nw'),
tnc.create_s_node('w'),
tnc.create_h_node(prob_dist, 'Z', 'sw'),
]
mpo = [
tnc.create_s_node('n'),
tnc.create_v_node(prob_dist, 'Y'),
tnc.create_s_node('s'),
]
ket = [
tnc.create_h_node(prob_dist, 'Z', 'ne'),
tnc.create_s_node('e'),
tnc.create_h_node(prob_dist, 'I', 'se'),
]
# tensor network corresponding to column bra, mpo and ket
tn = np.array([bra, mpo, ket], dtype=object).transpose()
expected = 0.00096790123456790152
# exact contraction for expected
result = tt.mps.contract_pairwise(bra, mpo)
result = tt.mps.inner_product(result, ket)
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(expected, result, rtol=1e-14,
atol=0), 'Exact contraction not as expected'
# exact contraction with contract_ladder
result = tt.mps.contract_pairwise(bra, mpo)
result = tt.mps.contract_pairwise(result, ket)
result = tt.mps.contract_ladder(result)[0, 0, 0, 0]
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(expected, result, rtol=1e-14,
atol=0), 'Exact contraction not as expected'
# exact contraction with lcf
result = tt.mps.left_canonical_form(bra)
result = tt.mps.contract_pairwise(result, mpo)
result = tt.mps.left_canonical_form(result)
result = tt.mps.inner_product(result, ket)
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(expected, result, rtol=1e-14,
atol=0), 'Exact contraction with lcf not as expected'
# exact contraction with rcf
result = tt.mps.right_canonical_form(bra)
result = tt.mps.contract_pairwise(result, mpo)
result = tt.mps.right_canonical_form(result)
result = tt.mps.inner_product(result, ket)
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(expected, result, rtol=1e-14,
atol=0), 'Exact contraction with rcf not as expected'
# exact contraction with truncate
result = tt.mps.contract_pairwise(bra, mpo)
result, norm = tt.mps.truncate(result)
result = tt.mps.inner_product(result, ket)
result *= norm
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(expected, result, rtol=1e-14,
atol=0), 'Exact contraction with truncate not as expected'
# exact contraction with normalise lcf
result, norm1 = tt.mps.left_canonical_form(bra, normalise=True)
result = tt.mps.contract_pairwise(result, mpo)
result, norm2 = tt.mps.left_canonical_form(result, normalise=True)
result = tt.mps.inner_product(result, ket)
result *= norm1 * norm2
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(
expected, result, rtol=1e-14,
atol=0), 'Exact contraction with normalise lcf not as expected'
# exact contraction with normalise rcf
result, norm1 = tt.mps.right_canonical_form(bra, normalise=True)
result = tt.mps.contract_pairwise(result, mpo)
result, norm2 = tt.mps.right_canonical_form(result, normalise=True)
result = tt.mps.inner_product(result, ket)
result *= norm1 * norm2
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(
expected, result, rtol=1e-14,
atol=0), 'Exact contraction with normalise rcf not as expected'
# approximate contraction with truncate (chi)
result = tt.mps.contract_pairwise(bra, mpo)
result, norm = tt.mps.truncate(result, chi=2)
result = tt.mps.inner_product(result, ket)
result *= norm
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(
expected, result, rtol=1e-14,
atol=0), 'Approx. contraction with truncate (chi) not as expected'
# approximate contraction with truncate (tol)
result = tt.mps.contract_pairwise(bra, mpo)
result, norm = tt.mps.truncate(result, tol=1e-8)
result = tt.mps.inner_product(result, ket)
result *= norm
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(
expected, result, rtol=1e-14,
atol=0), 'Approx. contraction with truncate (tol) not as expected'
# tn_contract
result = tt.mps2d.contract(tn)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(expected, result, rtol=1e-14,
atol=0), 'Exact tn contraction not as expected'
# tn_contract with truncate (chi)
result = tt.mps2d.contract(tn, chi=2)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(
expected, result, rtol=1e-14,
atol=0), 'Approx. tn contraction with truncate (chi) not as expected'
# tn_contract with truncate (tol)
result = tt.mps2d.contract(tn, tol=1e-8)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(
expected, result, rtol=1e-14,
atol=0), 'Approx. tn contraction with truncate (tol) not as expected'
# tn_contract with truncate (chi, mask)
stp = 0.2 # skip truncate probability
mask = rng.choice((True, False), size=tn.shape, p=(1 - stp, stp))
result = tt.mps2d.contract(tn, chi=2, mask=mask)
assert isinstance(result,
mp.mpf), 'Contracted tensor network is not an mp.mpf'
print('#result=', result, '#rtol=', abs(result - expected) / abs(expected))
assert _is_close(expected, result, rtol=1e-14, atol=0), (
'Approx. tn contraction with truncate (chi, mask) not as expected')