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""" | |
This script provides an example to wrap TencentPretrain for feature extraction. | |
""" | |
import sys | |
import os | |
import torch | |
import torch.nn as nn | |
import argparse | |
import numpy as np | |
tencentpretrain_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), "..")) | |
sys.path.append(tencentpretrain_dir) | |
from tencentpretrain.embeddings import * | |
from tencentpretrain.encoders import * | |
from tencentpretrain.targets import * | |
from tencentpretrain.utils.constants import * | |
from tencentpretrain.utils import * | |
from tencentpretrain.utils.config import load_hyperparam | |
from tencentpretrain.utils.misc import pooling | |
from tencentpretrain.model_loader import load_model | |
from tencentpretrain.opts import infer_opts, tokenizer_opts | |
def batch_loader(batch_size, src, seg): | |
instances_num = src.size(0) | |
for i in range(instances_num // batch_size): | |
src_batch = src[i * batch_size : (i + 1) * batch_size] | |
seg_batch = seg[i * batch_size : (i + 1) * batch_size] | |
yield src_batch, seg_batch | |
if instances_num > instances_num // batch_size * batch_size: | |
src_batch = src[instances_num // batch_size * batch_size:] | |
seg_batch = seg[instances_num // batch_size * batch_size:] | |
yield src_batch, seg_batch | |
def read_dataset(args, path): | |
dataset = [] | |
PAD_ID = args.tokenizer.vocab.get(PAD_TOKEN) | |
with open(path, mode="r", encoding="utf-8") as f: | |
for line in f: | |
src = args.tokenizer.convert_tokens_to_ids(args.tokenizer.tokenize(line)) | |
if len(src) == 0: | |
continue | |
src = args.tokenizer.convert_tokens_to_ids([CLS_TOKEN]) + src + args.tokenizer.convert_tokens_to_ids([SEP_TOKEN]) | |
seg = [1] * len(src) | |
if len(src) > args.seq_length: | |
src = src[:args.seq_length] | |
seg = seg[:args.seq_length] | |
while len(src) < args.seq_length: | |
src.append(PAD_ID) | |
seg.append(PAD_ID) | |
dataset.append((src, seg)) | |
return dataset | |
class FeatureExtractor(torch.nn.Module): | |
def __init__(self, args): | |
super(FeatureExtractor, self).__init__() | |
self.embedding = Embedding(args) | |
for embedding_name in args.embedding: | |
tmp_emb = str2embedding[embedding_name](args, len(args.tokenizer.vocab)) | |
self.embedding.update(tmp_emb, embedding_name) | |
self.encoder = str2encoder[args.encoder](args) | |
self.pooling_type = args.pooling | |
def forward(self, src, seg): | |
emb = self.embedding(src, seg) | |
output = self.encoder(emb, seg) | |
output = pooling(output, seg, self.pooling_type) | |
return output | |
class WhiteningHandle(torch.nn.Module): | |
""" | |
Whitening operation. | |
@ref: https://github.com/bojone/BERT-whitening/blob/main/demo.py | |
""" | |
def __init__(self, args, vecs): | |
super(WhiteningHandle, self).__init__() | |
self.kernel, self.bias = self._compute_kernel_bias(vecs) | |
def forward(self, vecs, n_components=None, normal=True, pt=True): | |
vecs = self._format_vecs_to_np(vecs) | |
vecs = self._transform(vecs, n_components) | |
vecs = self._normalize(vecs) if normal else vecs | |
vecs = torch.tensor(vecs) if pt else vecs | |
return vecs | |
def _compute_kernel_bias(self, vecs): | |
vecs = self._format_vecs_to_np(vecs) | |
mu = vecs.mean(axis=0, keepdims=True) | |
cov = np.cov(vecs.T) | |
u, s, vh = np.linalg.svd(cov) | |
W = np.dot(u, np.diag(1 / np.sqrt(s))) | |
return W, -mu | |
def _transform(self, vecs, n_components): | |
w = self.kernel[:, :n_components] \ | |
if isinstance(n_components, int) else self.kernel | |
return (vecs + self.bias).dot(w) | |
def _normalize(self, vecs): | |
return vecs / (vecs**2).sum(axis=1, keepdims=True)**0.5 | |
def _format_vecs_to_np(self, vecs): | |
vecs_np = [] | |
for vec in vecs: | |
if isinstance(vec, list): | |
vec = np.array(vec) | |
elif torch.is_tensor(vec): | |
vec = vec.detach().numpy() | |
elif isinstance(vec, np.ndarray): | |
vec = vec | |
else: | |
raise Exception('Unknown vec type.') | |
vecs_np.append(vec) | |
vecs_np = np.array(vecs_np) | |
return vecs_np | |
if __name__ == '__main__': | |
parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter) | |
infer_opts(parser) | |
parser.add_argument("--whitening_size", type=int, default=None, help="Output vector size after whitening.") | |
tokenizer_opts(parser) | |
args = parser.parse_args() | |
args = load_hyperparam(args) | |
args.tokenizer = str2tokenizer[args.tokenizer](args) | |
# Build feature extractor model. | |
model = FeatureExtractor(args) | |
model = load_model(model, args.load_model_path) | |
# For simplicity, we use DataParallel wrapper to use multiple GPUs. | |
device = torch.device("cuda" if torch.cuda.is_available() else "cpu") | |
model = model.to(device) | |
if torch.cuda.device_count() > 1: | |
print("{} GPUs are available. Let's use them.".format(torch.cuda.device_count())) | |
model = nn.DataParallel(model) | |
model.eval() | |
dataset = read_dataset(args, args.test_path) | |
src = torch.LongTensor([sample[0] for sample in dataset]) | |
seg = torch.LongTensor([sample[1] for sample in dataset]) | |
feature_vectors = [] | |
for i, (src_batch, seg_batch) in enumerate(batch_loader(args.batch_size, src, seg)): | |
src_batch = src_batch.to(device) | |
seg_batch = seg_batch.to(device) | |
output = model(src_batch, seg_batch) | |
feature_vectors.append(output.cpu().detach()) | |
feature_vectors = torch.cat(feature_vectors, 0) | |
# Vector whitening. | |
if args.whitening_size is not None: | |
whitening = WhiteningHandle(args, feature_vectors) | |
feature_vectors = whitening(feature_vectors, args.whitening_size, pt=True) | |
print("The size of feature vectors (sentences_num * vector size): {}".format(feature_vectors.shape)) | |
torch.save(feature_vectors, args.prediction_path) | |