def decode(self, x_tree_vecs, prob_decode):
assert x_tree_vecs.size(0) == 1
stack = []
init_hiddens = create_var(torch.zeros(1, self.hidden_size))
zero_pad = create_var(torch.zeros(1, 1, self.hidden_size))
contexts = create_var(torch.LongTensor(1).zero_())
#Root Prediction
root_score = self.aggregate(init_hiddens, contexts, x_tree_vecs,
'word')
_, root_wid = torch.max(root_score, dim=1)
root_wid = root_wid.item()
root = MolTreeNode(self.vocab.get_smiles(root_wid))
root.wid = root_wid
root.idx = 0
stack.append((root, self.vocab.get_slots(root.wid)))
all_nodes = [root]
h = {}
for step in xrange(MAX_DECODE_LEN):
node_x, fa_slot = stack[-1]
cur_h_nei = [
h[(node_y.idx, node_x.idx)] for node_y in node_x.neighbors
]
if len(cur_h_nei) > 0:
cur_h_nei = torch.stack(cur_h_nei,
dim=0).view(1, -1, self.hidden_size)
else:
cur_h_nei = zero_pad
cur_x = create_var(torch.LongTensor([node_x.wid]))
cur_x = self.embedding(cur_x)
#Predict stop
cur_h = cur_h_nei.sum(dim=1)
stop_hiddens = torch.cat([cur_x, cur_h], dim=1)
stop_hiddens = F.relu(self.U_i(stop_hiddens))
stop_score = self.aggregate(stop_hiddens, contexts, x_tree_vecs,
'stop')
if prob_decode:
backtrack = (torch.bernoulli(
torch.sigmoid(stop_score)).item() == 0)
else:
backtrack = (stop_score.item() < 0)
if not backtrack: #Forward: Predict next clique
new_h = GRU(cur_x, cur_h_nei, self.W_z, self.W_r, self.U_r,
self.W_h)
pred_score = self.aggregate(new_h, contexts, x_tree_vecs,
'word')
if prob_decode:
sort_wid = torch.multinomial(
F.softmax(pred_score, dim=1).squeeze(), 5)
else:
_, sort_wid = torch.sort(pred_score,
dim=1,
descending=True)
sort_wid = sort_wid.data.squeeze()
next_wid = None
for wid in sort_wid[:5]:
slots = self.vocab.get_slots(wid)
node_y = MolTreeNode(self.vocab.get_smiles(wid))
if have_slots(fa_slot, slots) and can_assemble(
node_x, node_y):
next_wid = wid
next_slots = slots
break
if next_wid is None:
backtrack = True #No more children can be added
else:
node_y = MolTreeNode(self.vocab.get_smiles(next_wid))
node_y.wid = next_wid
node_y.idx = len(all_nodes)
node_y.neighbors.append(node_x)
h[(node_x.idx, node_y.idx)] = new_h[0]
stack.append((node_y, next_slots))
all_nodes.append(node_y)
if backtrack: #Backtrack, use if instead of else
if len(stack) == 1:
break #At root, terminate
node_fa, _ = stack[-2]
cur_h_nei = [
h[(node_y.idx, node_x.idx)] for node_y in node_x.neighbors
if node_y.idx != node_fa.idx
]
if len(cur_h_nei) > 0:
cur_h_nei = torch.stack(cur_h_nei, dim=0).view(
1, -1, self.hidden_size)
else:
cur_h_nei = zero_pad
new_h = GRU(cur_x, cur_h_nei, self.W_z, self.W_r, self.U_r,
self.W_h)
h[(node_x.idx, node_fa.idx)] = new_h[0]
node_fa.neighbors.append(node_x)
stack.pop()
return root, all_nodes
def get_subtree(tree, edge, x_node_vecs, x_mess_dict):
subtree_list = {}
node_tree_idx = {}
node_list = {}
# ========================= Get Subtree List ===============================
tree.nodes[0].keep_neighbors = []
for i, node in enumerate(tree.nodes[1:]):
fa_node = node.fa_node
node_idx = node.idx
idx = x_mess_dict[node.fa_node.idx, node.idx]
if not edge[idx]:
if fa_node in node_tree_idx:
new_node = MolTreeNode(node.smiles)
new_node.wid = node.wid
new_node.neighbors = [node.fa_node.cnode]
new_node.idx = node_idx
node.cnode = new_node
node.fa_node.cnode.neighbors.append(new_node)
node_tree_idx[node] = node_tree_idx[node.fa_node]
tree_node = node_tree_idx[node.fa_node]
subtree_list[tree_node].add_node(new_node)
else:
new_fa_node = MolTreeNode(node.fa_node.smiles)
new_fa_node.wid = fa_node.wid
new_fa_node.idx = fa_node.idx
new_node = MolTreeNode(node.smiles)
new_node.wid = node.wid
new_node.idx = node_idx
new_fa_node.neighbors = [new_node]
new_node.neighbors = [new_fa_node]
node.cnode = new_node
node.fa_node.cnode = new_fa_node
subtree_list[new_fa_node] = Subtree(new_fa_node)
subtree_list[new_fa_node].add_node(new_node)
node_tree_idx[fa_node] = new_fa_node
node_tree_idx[node] = new_fa_node
if node.fa_node.wid in node_list:
node_list[node.fa_node.wid].append((new_fa_node, new_fa_node))
else:
node_list[node.fa_node.wid] = [(new_fa_node, new_fa_node)]
fa_node = node_tree_idx[node]
if node.wid in node_list:
node_list[node.wid].append((fa_node, node))
else:
node_list[node.wid] = [(fa_node, node)]
# ========================= Subtree Embedding ==============================
max_idx, max_num = 0, 0
if len(subtree_list) > 1:
for idx in subtree_list:
if len(subtree_list[idx].nodes) > max_num:
max_num = len(subtree_list[idx].nodes)
max_idx = idx
max_subtree = subtree_list[max_idx]
else:
max_subtree = subtree_list[list(subtree_list.keys())[0]]
for i, node in enumerate(max_subtree.nodes):
node.idx = i
node.nid = i
return subtree_list, max_subtree, node_tree_idx, node_list
def decode(self, mol_vec, prob_decode):
stack, trace = [], []
init_hidden = create_var(torch.zeros(1, self.hidden_size))
zero_pad = create_var(torch.zeros(1, 1, self.hidden_size))
#Root Prediction
root_hidden = torch.cat([init_hidden, mol_vec], dim=1)
root_hidden = nn.ReLU()(self.W(root_hidden))
root_score = self.W_o(root_hidden)
_, root_wid = torch.max(root_score, dim=1)
root_wid = root_wid.item()
root = MolTreeNode(self.vocab.get_smiles(root_wid))
root.wid = root_wid
root.idx = 0
stack.append((root, self.vocab.get_slots(root.wid)))
all_nodes = [root]
h = {}
for step in xrange(MAX_DECODE_LEN):
node_x, fa_slot = stack[-1]
cur_h_nei = [
h[(node_y.idx, node_x.idx)] for node_y in node_x.neighbors
]
if len(cur_h_nei) > 0:
cur_h_nei = torch.stack(cur_h_nei,
dim=0).view(1, -1, self.hidden_size)
else:
cur_h_nei = zero_pad
cur_x = create_var(torch.LongTensor([node_x.wid]))
cur_x = self.embedding(cur_x)
#Predict stop
cur_h = cur_h_nei.sum(dim=1)
stop_hidden = torch.cat([cur_x, cur_h, mol_vec], dim=1)
stop_hidden = nn.ReLU()(self.U(stop_hidden))
stop_score = nn.Sigmoid()(self.U_s(stop_hidden) * 20).squeeze()
if prob_decode:
backtrack = (torch.bernoulli(1.0 - stop_score.data)[0] == 1)
else:
backtrack = (stop_score.item() < 0.5)
if not backtrack: #Forward: Predict next clique
new_h = GRU(cur_x, cur_h_nei, self.W_z, self.W_r, self.U_r,
self.W_h)
pred_hidden = torch.cat([new_h, mol_vec], dim=1)
pred_hidden = nn.ReLU()(self.W(pred_hidden))
pred_score = nn.Softmax(dim=1)(self.W_o(pred_hidden) * 20)
if prob_decode:
sort_wid = torch.multinomial(pred_score.data.squeeze(), 5)
else:
_, sort_wid = torch.sort(pred_score,
dim=1,
descending=True)
sort_wid = sort_wid.data.squeeze()
next_wid = None
for wid in sort_wid[:5]:
slots = self.vocab.get_slots(wid)
node_y = MolTreeNode(self.vocab.get_smiles(wid))
if have_slots(fa_slot, slots) and can_assemble(
node_x, node_y):
next_wid = wid
next_slots = slots
break
if next_wid is None:
backtrack = True #No more children can be added
else:
node_y = MolTreeNode(self.vocab.get_smiles(next_wid))
node_y.wid = next_wid
node_y.idx = step + 1
node_y.neighbors.append(node_x)
h[(node_x.idx, node_y.idx)] = new_h[0]
stack.append((node_y, next_slots))
all_nodes.append(node_y)
if backtrack: #Backtrack, use if instead of else
if len(stack) == 1:
break #At root, terminate
node_fa, _ = stack[-2]
cur_h_nei = [
h[(node_y.idx, node_x.idx)] for node_y in node_x.neighbors
if node_y.idx != node_fa.idx
]
if len(cur_h_nei) > 0:
cur_h_nei = torch.stack(cur_h_nei, dim=0).view(
1, -1, self.hidden_size)
else:
cur_h_nei = zero_pad
new_h = GRU(cur_x, cur_h_nei, self.W_z, self.W_r, self.U_r,
self.W_h)
h[(node_x.idx, node_fa.idx)] = new_h[0]
node_fa.neighbors.append(node_x)
stack.pop()
return root, all_nodes
