def test_contract_copy_node_dangling_edge_value_error(backend):
a = tn.Node(np.array([1, 2, 3]), backend=backend)
b = tn.Node(np.array([10, 20, 30]), backend=backend)
c = tn.Node(np.array([5, 6, 7]), backend=backend)
cn = tn.CopyNode(rank=4, dimension=3, backend=backend)
tn.connect(a[0], cn[0])
tn.connect(b[0], cn[1])
tn.connect(c[0], cn[2])
with pytest.raises(ValueError):
tn.contract_copy_node(cn)
def test_contract_copy_node(backend):
a = tn.Node(np.array([1, 2, 3]), backend=backend)
b = tn.Node(np.array([10, 20, 30]), backend=backend)
c = tn.Node(np.array([5, 6, 7]), backend=backend)
d = tn.Node(np.array([1, -1, 1]), backend=backend)
cn = tn.CopyNode(rank=4, dimension=3, backend=backend)
tn.connect(a[0], cn[0])
tn.connect(b[0], cn[1])
tn.connect(c[0], cn[2])
tn.connect(d[0], cn[3])
val = tn.contract_copy_node(cn)
result = val.tensor
assert list(result.shape) == []
np.testing.assert_allclose(result, 50 - 240 + 630)
def test_contract_copy_node_connected_neighbors(backend):
a = tn.Node(np.array([[1, 2, 3], [10, 20, 30]]), backend=backend)
b = tn.Node(np.array([[2, 1, 1], [2, 2, 2]]), backend=backend)
c = tn.Node(np.array([3, 4, 4]), backend=backend)
cn = tn.CopyNode(rank=3, dimension=3, backend=backend)
tn.connect(a[0], b[0])
tn.connect(a[1], cn[0])
tn.connect(b[1], cn[1])
tn.connect(c[0], cn[2])
n = tn.contract_copy_node(cn)
assert len(n.edges) == 2
assert n.edges[0] == n.edges[1]
val = tn.contract_parallel(n.edges[0])
result = val.tensor
assert list(result.shape) == []
np.testing.assert_allclose(result, 26 + 460)
