def test_mps_swap():
L = 6
# starting from ordered pairs with infinite bc (the latter shouldn't make a difference).
pairs = [(0, 1), (2, 3), (4, 5)]
perm = rand_permutation(L)
pairs_perm = [(perm[i], perm[j]) for i, j in pairs]
psi = mps.MPS.from_singlets(spin_half, L, pairs, bc='infinite')
psi.permute_sites(perm)
psi_perm = mps.MPS.from_singlets(spin_half, L, pairs_perm, bc='finite')
print(psi.overlap(psi_perm), psi.norm_test())
assert abs(abs(psi.overlap(psi_perm)) - 1.) < 1.e-10
# now start from random pairs
pairs = [(0, 3), (1, 5), (2, 4)]
pairs_swap = [(0, 2), (1, 5), (3, 4)]
print("singlet pairs: ", pairs)
psi = mps.MPS.from_singlets(spin_half, L, pairs, bc='finite')
psi_swap = mps.MPS.from_singlets(spin_half, L, pairs_swap, bc='finite')
psi.swap_sites(2)
assert abs(psi.overlap(psi_swap) - 1.) < 1.e-15
# now test permutation
# recover original psi
psi = mps.MPS.from_singlets(spin_half, L, pairs, bc='finite')
perm = rand_permutation(L)
pairs_perm = [(perm[i], perm[j]) for i, j in pairs]
psi_perm = mps.MPS.from_singlets(spin_half, L, pairs_perm, bc='finite')
psi.permute_sites(perm)
print(psi.overlap(psi_perm), psi.norm_test())
assert abs(abs(psi.overlap(psi_perm)) - 1.) < 1.e-10
def setup_npc(mod_q=[1],
n_qsectors=3,
size=20,
leg_a_out=2,
leg_b_out=2,
leg_contract=2,
select_frac=1.,
dtype=np.float,
seed=123):
"""Returns ``a, b, axes`` for timing of ``npc.tensordot(a, b, axes)``
Constructed such that leg_contract legs are contracted, with
a.rank = leg_a_out + leg_contract
b.rank = leg_b_out + leg_contract
If `select_frac` < 1, select only the given fraction of blocks compared to what is possible by
charge requirements.
"""
chinfo = npc.ChargeInfo(mod_q)
np.random.seed(seed)
legs_contr = [
gen_random_legcharge_nq(chinfo, size, n_qsectors)
for i in range(leg_contract)
]
legs_a = legs_contr + \
[gen_random_legcharge_nq(chinfo, size, n_qsectors) for i in range(leg_a_out)]
legs_b = [l.conj() for l in legs_contr] + \
[gen_random_legcharge_nq(chinfo, size, n_qsectors) for i in range(leg_b_out)]
a = npc.Array.from_func(np.random.random, legs_a, dtype, shape_kw='size')
b = npc.Array.from_func(np.random.random, legs_b, dtype, shape_kw='size')
a.ipurge_zeros()
b.ipurge_zeros()
if chinfo.qnumber > 0 and select_frac < 1.:
a_bl = a.stored_blocks
if a_bl > 0:
a_subset = rand_distinct_int(0, a_bl - 1,
max(int(a_bl * select_frac), 1))
a._qdata = a._qdata[a_subset, :]
a._data = [a._data[i] for i in a_subset]
b_bl = a.stored_blocks
if b_bl > 0:
b_subset = rand_distinct_int(0, b_bl - 1,
max(int(b_bl * select_frac), 1))
b._qdata = b._qdata[b_subset, :]
b._data = [b._data[i] for i in b_subset]
labs = [
"l{i:d}".format(i=i)
for i in range(max(leg_a_out, leg_b_out) + leg_contract)
]
a.iset_leg_labels(labs[:a.rank])
b.iset_leg_labels(labs[:b.rank])
a.itranspose(rand_permutation(a.rank))
b.itranspose(rand_permutation(b.rank))
axes = [labs[:leg_contract]] * 2
return a, b, axes
def test_mps_swap():
L = 6
pairs = [(0, 3), (1, 5), (2, 4)]
pairs_swap = [(0, 2), (1, 5), (3, 4)]
print("singlet pairs: ", pairs)
psi = mps.MPS.from_singlets(spin_half, L, pairs, bc='finite')
psi_swap = mps.MPS.from_singlets(spin_half, L, pairs_swap, bc='finite')
psi.swap_sites(2)
assert abs(psi.overlap(psi_swap) - 1.) < 1.e-15
# now test permutation
# recover original psi
psi = mps.MPS.from_singlets(spin_half, L, pairs, bc='finite')
perm = rand_permutation(L)
pairs_perm = [(perm[i], perm[j]) for i, j in pairs]
psi_perm = mps.MPS.from_singlets(spin_half, L, pairs_perm, bc='finite')
psi.permute_sites(perm, verbose=2)
print(psi.overlap(psi_perm), psi.norm_test())
assert abs(abs(psi.overlap(psi_perm)) - 1.) < 1.e-10
