def test_bsz2_start_left(self):
tn = MPS_rand_state(6, bond_dim=7)
env = MovingEnvironment(tn, begin='left', bsz=2)
assert len(env().tensors) == 4
env.move_right()
assert len(env().tensors) == 4
env.move_right()
assert len(env().tensors) == 4
with pytest.raises(ValueError):
env.move_to(5)
env.move_to(4)
assert env.pos == 4
assert len(env().tensors) == 4
def test_bsz1_start_left(self):
tn = MPS_rand_state(6, bond_dim=7)
env = MovingEnvironment(tn, begin='left', bsz=1)
assert env.pos == 0
assert len(env().tensors) == 3
env.move_right()
assert env.pos == 1
assert len(env().tensors) == 3
env.move_right()
assert env.pos == 2
assert len(env().tensors) == 3
env.move_to(5)
assert env.pos == 5
assert len(env().tensors) == 3
def test_cyclic_moving_env_init_left(self, n, bsz, ssz):
nenv = 2
p = MPS_rand_state(n, 4, cyclic=True)
norm = p.H & p
mes = MovingEnvironment(norm, begin='left', bsz=bsz,
cyclic=True, ssz=ssz)
assert len(mes.envs) == n // 2 + n % 2
assert mes.pos == 0
assert len(mes.envs[0].tensors) == 2 * bsz + nenv
assert len(mes.envs[n // 2 - 1].tensors) == 2 * bsz + 1
assert n // 2 + n % 2 not in mes.envs
assert n - 1 not in mes.envs
for i in range(1, 2 * n):
mes.move_right()
assert mes.pos == i % n
cur_env = mes()
assert len(cur_env.tensors) == 2 * bsz + nenv
assert (cur_env ^ all) == pytest.approx(1.0)