def test_compress_form(self):
p = MPS_rand_state(20, 20)
p.compress('left')
assert p.count_canonized() == (19, 0)
p.compress('right')
assert p.count_canonized() == (0, 19)
p.compress(7)
assert p.count_canonized() == (7, 12)
p = MPS_rand_state(20, 20)
p.compress('flat', absorb='left')
assert p.count_canonized() == (0, 0)
def test_gate2split(self):
psi = MPS_rand_state(10, 3)
psi2 = psi.copy()
G = qu.eye(2) & qu.eye(2)
psi.gate2split(G, (2, 3), cutoff=0)
assert psi.bond_size(2, 3) == 6
assert psi.H @ psi2 == pytest.approx(1.0)
# check a unitary application
G = qu.rand_uni(2**2)
psi.gate2split(G, (7, 8))
psi.compress()
assert psi.bond_size(2, 3) == 3
assert psi.bond_size(7, 8) > 3
assert psi.H @ psi == pytest.approx(1.0)
assert abs(psi2.H @ psi) < 1.0
# check matches dense application of gate
psid = psi2.to_dense()
Gd = qu.ikron(G, [2] * 10, (7, 8))
assert psi.to_dense().H @ (Gd @ psid) == pytest.approx(1.0)