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2026-07-13 13:35:51 +08:00

227 lines
7.7 KiB
Python
Executable File

import math
import torch
import torch.nn.functional as F
from torch import nn
from torch.nn.utils.rnn import pack_padded_sequence, pad_packed_sequence
from utlis import *
import dgl.function as fn
from dgl.nn.functional import edge_softmax
class MSA(nn.Module):
# multi-head self-attention, three modes
# the first is the copy, determining which entity should be copied.
# the second is the normal attention with two sequence inputs
# the third is the attention but with one token and a sequence. (gather, attentive pooling)
def __init__(self, args, mode="normal"):
super(MSA, self).__init__()
if mode == "copy":
nhead, head_dim = 1, args.nhid
qninp, kninp = args.dec_ninp, args.nhid
if mode == "normal":
nhead, head_dim = args.nhead, args.head_dim
qninp, kninp = args.nhid, args.nhid
self.attn_drop = nn.Dropout(0.1)
self.WQ = nn.Linear(
qninp, nhead * head_dim, bias=True if mode == "copy" else False
)
if mode != "copy":
self.WK = nn.Linear(kninp, nhead * head_dim, bias=False)
self.WV = nn.Linear(kninp, nhead * head_dim, bias=False)
self.args, self.nhead, self.head_dim, self.mode = (
args,
nhead,
head_dim,
mode,
)
def forward(self, inp1, inp2, mask=None):
B, L2, H = inp2.shape
NH, HD = self.nhead, self.head_dim
if self.mode == "copy":
q, k, v = self.WQ(inp1), inp2, inp2
else:
q, k, v = self.WQ(inp1), self.WK(inp2), self.WV(inp2)
L1 = 1 if inp1.ndim == 2 else inp1.shape[1]
if self.mode != "copy":
q = q / math.sqrt(H)
q = q.view(B, L1, NH, HD).permute(0, 2, 1, 3)
k = k.view(B, L2, NH, HD).permute(0, 2, 3, 1)
v = v.view(B, L2, NH, HD).permute(0, 2, 1, 3)
pre_attn = torch.matmul(q, k)
if mask is not None:
pre_attn = pre_attn.masked_fill(mask[:, None, None, :], -1e8)
if self.mode == "copy":
return pre_attn.squeeze(1)
else:
alpha = self.attn_drop(torch.softmax(pre_attn, -1))
attn = (
torch.matmul(alpha, v)
.permute(0, 2, 1, 3)
.contiguous()
.view(B, L1, NH * HD)
)
ret = attn
if inp1.ndim == 2:
return ret.squeeze(1)
else:
return ret
class BiLSTM(nn.Module):
# for entity encoding or the title encoding
def __init__(self, args, enc_type="title"):
super(BiLSTM, self).__init__()
self.enc_type = enc_type
self.drop = nn.Dropout(args.emb_drop)
self.bilstm = nn.LSTM(
args.nhid,
args.nhid // 2,
bidirectional=True,
num_layers=args.enc_lstm_layers,
batch_first=True,
)
def forward(self, inp, mask, ent_len=None):
inp = self.drop(inp)
lens = (mask == 0).sum(-1).long().tolist()
pad_seq = pack_padded_sequence(
inp, lens, batch_first=True, enforce_sorted=False
)
y, (_h, _c) = self.bilstm(pad_seq)
if self.enc_type == "title":
y = pad_packed_sequence(y, batch_first=True)[0]
return y
if self.enc_type == "entity":
_h = _h.transpose(0, 1).contiguous()
_h = _h[:, -2:].view(
_h.size(0), -1
) # two directions of the top-layer
ret = pad(_h.split(ent_len), out_type="tensor")
return ret
class GAT(nn.Module):
# a graph attention network with dot-product attention
def __init__(
self,
in_feats,
out_feats,
num_heads,
ffn_drop=0.0,
attn_drop=0.0,
trans=True,
):
super(GAT, self).__init__()
self._num_heads = num_heads
self._in_feats = in_feats
self._out_feats = out_feats
self.q_proj = nn.Linear(in_feats, num_heads * out_feats, bias=False)
self.k_proj = nn.Linear(in_feats, num_heads * out_feats, bias=False)
self.v_proj = nn.Linear(in_feats, num_heads * out_feats, bias=False)
self.attn_drop = nn.Dropout(0.1)
self.ln1 = nn.LayerNorm(in_feats)
self.ln2 = nn.LayerNorm(in_feats)
if trans:
self.FFN = nn.Sequential(
nn.Linear(in_feats, 4 * in_feats),
nn.PReLU(4 * in_feats),
nn.Linear(4 * in_feats, in_feats),
nn.Dropout(0.1),
)
# a strange FFN, see the author's code
self._trans = trans
def forward(self, graph, feat):
graph = graph.local_var()
feat_c = feat.clone().detach().requires_grad_(False)
q, k, v = self.q_proj(feat), self.k_proj(feat_c), self.v_proj(feat_c)
q = q.view(-1, self._num_heads, self._out_feats)
k = k.view(-1, self._num_heads, self._out_feats)
v = v.view(-1, self._num_heads, self._out_feats)
graph.ndata.update(
{"ft": v, "el": k, "er": q}
) # k,q instead of q,k, the edge_softmax is applied on incoming edges
# compute edge attention
graph.apply_edges(fn.u_dot_v("el", "er", "e"))
e = graph.edata.pop("e") / math.sqrt(self._out_feats * self._num_heads)
graph.edata["a"] = edge_softmax(graph, e)
# message passing
graph.update_all(fn.u_mul_e("ft", "a", "m"), fn.sum("m", "ft2"))
rst = graph.ndata["ft2"]
# residual
rst = rst.view(feat.shape) + feat
if self._trans:
rst = self.ln1(rst)
rst = self.ln1(rst + self.FFN(rst))
# use the same layer norm, see the author's code
return rst
class GraphTrans(nn.Module):
def __init__(self, args):
super().__init__()
self.args = args
if args.graph_enc == "gat":
# we only support gtrans, don't use this one
self.gat = nn.ModuleList(
[
GAT(
args.nhid,
args.nhid // 4,
4,
attn_drop=args.attn_drop,
trans=False,
)
for _ in range(args.prop)
]
) # untested
else:
self.gat = nn.ModuleList(
[
GAT(
args.nhid,
args.nhid // 4,
4,
attn_drop=args.attn_drop,
ffn_drop=args.drop,
trans=True,
)
for _ in range(args.prop)
]
)
self.prop = args.prop
def forward(self, ent, ent_mask, ent_len, rel, rel_mask, graphs):
device = ent.device
graphs = graphs.to(device)
ent_mask = ent_mask == 0 # reverse mask
rel_mask = rel_mask == 0
init_h = []
for i in range(graphs.batch_size):
init_h.append(ent[i][ent_mask[i]])
init_h.append(rel[i][rel_mask[i]])
init_h = torch.cat(init_h, 0)
feats = init_h
for i in range(self.prop):
feats = self.gat[i](graphs, feats)
g_root = feats.index_select(
0,
graphs.filter_nodes(
lambda x: x.data["type"] == NODE_TYPE["root"]
).to(device),
)
g_ent = pad(
feats.index_select(
0,
graphs.filter_nodes(
lambda x: x.data["type"] == NODE_TYPE["entity"]
).to(device),
).split(ent_len),
out_type="tensor",
)
return g_ent, g_root