def forward(self, x: Tensor, edge_index: Adj) -> Tensor:
""""""
edge_weight: OptTensor = None
if isinstance(edge_index, Tensor):
num_nodes = x.size(self.node_dim)
if self.add_self_loops:
edge_index, _ = remove_self_loops(edge_index)
edge_index, _ = add_self_loops(edge_index, num_nodes=num_nodes)
row, col = edge_index[0], edge_index[1]
deg_inv = 1. / degree(col, num_nodes=num_nodes).clamp_(1.)
edge_weight = deg_inv[col]
edge_weight[row == col] += self.diag_lambda * deg_inv
elif isinstance(edge_index, SparseTensor):
if self.add_self_loops:
edge_index = set_diag(edge_index)
col, row, _ = edge_index.coo() # Transposed.
deg_inv = 1. / sparsesum(edge_index, dim=1).clamp_(1.)
edge_weight = deg_inv[col]
edge_weight[row == col] += self.diag_lambda * deg_inv
edge_index = edge_index.set_value(edge_weight, layout='coo')
# propagate_type: (x: Tensor, edge_weight: OptTensor)
out = self.propagate(edge_index,
x=x,
edge_weight=edge_weight,
size=None)
out = self.lin_out(out) + self.lin_root(x)
return out
def gcn_norm(edge_index,
edge_weight=None,
num_nodes=None,
improved=False,
add_self_loops=True,
flow="source_to_target",
dtype=None):
fill_value = 2. if improved else 1.
if isinstance(edge_index, SparseTensor):
assert flow in ["source_to_target"]
adj_t = edge_index
if not adj_t.has_value():
adj_t = adj_t.fill_value(1., dtype=dtype)
if add_self_loops:
adj_t = fill_diag(adj_t, fill_value)
deg = sparsesum(adj_t, dim=1)
deg_inv_sqrt = deg.pow_(-0.5)
deg_inv_sqrt.masked_fill_(deg_inv_sqrt == float('inf'), 0.)
adj_t = mul(adj_t, deg_inv_sqrt.view(-1, 1))
adj_t = mul(adj_t, deg_inv_sqrt.view(1, -1))
return adj_t
else:
assert flow in ["source_to_target", "target_to_source"]
num_nodes = maybe_num_nodes(edge_index, num_nodes)
if edge_weight is None:
edge_weight = torch.ones((edge_index.size(1), ),
dtype=dtype,
device=edge_index.device)
if add_self_loops:
edge_index, tmp_edge_weight = add_remaining_self_loops(
edge_index, edge_weight, fill_value, num_nodes)
assert tmp_edge_weight is not None
edge_weight = tmp_edge_weight
row, col = edge_index[0], edge_index[1]
idx = col if flow == "source_to_target" else row
deg = scatter_add(edge_weight, idx, dim=0, dim_size=num_nodes)
deg_inv_sqrt = deg.pow_(-0.5)
deg_inv_sqrt.masked_fill_(deg_inv_sqrt == float('inf'), 0)
return edge_index, deg_inv_sqrt[row] * edge_weight * deg_inv_sqrt[col]