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| import torch | |
| import torch.nn as nn | |
| import torch.nn.functional as F | |
| from collections import deque | |
| from mol_tree import Vocab, MolTree | |
| from nnutils import create_var, index_select_ND | |
| class JTNNEncoder(nn.Module): | |
| def __init__(self, hidden_size, depth, embedding): | |
| super(JTNNEncoder, self).__init__() | |
| self.hidden_size = hidden_size | |
| self.depth = depth | |
| self.embedding = embedding | |
| self.outputNN = nn.Sequential( | |
| nn.Linear(2 * hidden_size, hidden_size), | |
| nn.ReLU() | |
| ) | |
| self.GRU = GraphGRU(hidden_size, hidden_size, depth=depth) | |
| def forward(self, fnode, fmess, node_graph, mess_graph, scope): | |
| fnode = create_var(fnode) | |
| fmess = create_var(fmess) | |
| node_graph = create_var(node_graph) | |
| mess_graph = create_var(mess_graph) | |
| messages = create_var(torch.zeros(mess_graph.size(0), self.hidden_size)) | |
| fnode = self.embedding(fnode) | |
| fmess = index_select_ND(fnode, 0, fmess) | |
| messages = self.GRU(messages, fmess, mess_graph) | |
| mess_nei = index_select_ND(messages, 0, node_graph) | |
| node_vecs = torch.cat([fnode, mess_nei.sum(dim=1)], dim=-1) | |
| node_vecs = self.outputNN(node_vecs) | |
| max_len = max([x for _,x in scope]) | |
| batch_vecs = [] | |
| for st,le in scope: | |
| cur_vecs = node_vecs[st] #Root is the first node | |
| batch_vecs.append( cur_vecs ) | |
| tree_vecs = torch.stack(batch_vecs, dim=0) | |
| return tree_vecs, messages | |
| def tensorize(tree_batch): | |
| node_batch = [] | |
| scope = [] | |
| for tree in tree_batch: | |
| scope.append( (len(node_batch), len(tree.nodes)) ) | |
| node_batch.extend(tree.nodes) | |
| return JTNNEncoder.tensorize_nodes(node_batch, scope) | |
| def tensorize_nodes(node_batch, scope): | |
| messages,mess_dict = [None],{} | |
| fnode = [] | |
| for x in node_batch: | |
| fnode.append(x.wid) | |
| for y in x.neighbors: | |
| mess_dict[(x.idx,y.idx)] = len(messages) | |
| messages.append( (x,y) ) | |
| node_graph = [[] for i in range(len(node_batch))] | |
| mess_graph = [[] for i in range(len(messages))] | |
| fmess = [0] * len(messages) | |
| for x,y in messages[1:]: | |
| mid1 = mess_dict[(x.idx,y.idx)] | |
| fmess[mid1] = x.idx | |
| node_graph[y.idx].append(mid1) | |
| for z in y.neighbors: | |
| if z.idx == x.idx: continue | |
| mid2 = mess_dict[(y.idx,z.idx)] | |
| mess_graph[mid2].append(mid1) | |
| max_len = max([len(t) for t in node_graph] + [1]) | |
| for t in node_graph: | |
| pad_len = max_len - len(t) | |
| t.extend([0] * pad_len) | |
| max_len = max([len(t) for t in mess_graph] + [1]) | |
| for t in mess_graph: | |
| pad_len = max_len - len(t) | |
| t.extend([0] * pad_len) | |
| mess_graph = torch.LongTensor(mess_graph) | |
| node_graph = torch.LongTensor(node_graph) | |
| fmess = torch.LongTensor(fmess) | |
| fnode = torch.LongTensor(fnode) | |
| return (fnode, fmess, node_graph, mess_graph, scope), mess_dict | |
| class GraphGRU(nn.Module): | |
| def __init__(self, input_size, hidden_size, depth): | |
| super(GraphGRU, self).__init__() | |
| self.hidden_size = hidden_size | |
| self.input_size = input_size | |
| self.depth = depth | |
| self.W_z = nn.Linear(input_size + hidden_size, hidden_size) | |
| self.W_r = nn.Linear(input_size, hidden_size, bias=False) | |
| self.U_r = nn.Linear(hidden_size, hidden_size) | |
| self.W_h = nn.Linear(input_size + hidden_size, hidden_size) | |
| def forward(self, h, x, mess_graph): | |
| mask = torch.ones(h.size(0), 1) | |
| mask[0] = 0 #first vector is padding | |
| mask = create_var(mask) | |
| for it in range(self.depth): | |
| h_nei = index_select_ND(h, 0, mess_graph) | |
| sum_h = h_nei.sum(dim=1) | |
| z_input = torch.cat([x, sum_h], dim=1) | |
| z = F.sigmoid(self.W_z(z_input)) | |
| r_1 = self.W_r(x).view(-1, 1, self.hidden_size) | |
| r_2 = self.U_r(h_nei) | |
| r = F.sigmoid(r_1 + r_2) | |
| gated_h = r * h_nei | |
| sum_gated_h = gated_h.sum(dim=1) | |
| h_input = torch.cat([x, sum_gated_h], dim=1) | |
| pre_h = F.tanh(self.W_h(h_input)) | |
| h = (1.0 - z) * sum_h + z * pre_h | |
| h = h * mask | |
| return h | |