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| 1 | +import torch.nn as nn |
| 2 | +import torch.nn.functional as F |
| 3 | +import os |
| 4 | +import torch |
| 5 | +from transformers import AutoConfig, AutoModel |
| 6 | + |
| 7 | +""" |
| 8 | +TextCNN is for uni-modal classification or just textual feature extractor (according to setting num_classes parameter) |
| 9 | +""" |
| 10 | + |
| 11 | + |
| 12 | +class TextCNN(nn.Module): |
| 13 | + def __init__(self, kernel_sizes, num_filters, num_classes, d_prob, mode='rand', dataset_name="Pheme"): |
| 14 | + """ |
| 15 | +
|
| 16 | + :param kernel_sizes: |
| 17 | + :param num_filters: |
| 18 | + :param num_classes: |
| 19 | + :param d_prob: |
| 20 | + :param mode: rand,roberta-yes,roberta-non, bert-yes, bert-non |
| 21 | + :param path_saved: |
| 22 | + """ |
| 23 | + |
| 24 | + super(TextCNN, self).__init__() |
| 25 | + self.kernel_sizes = kernel_sizes |
| 26 | + self.num_filters = num_filters |
| 27 | + self.num_classes = num_classes |
| 28 | + self.d_prob = d_prob |
| 29 | + # roberta-non bert-non bert-yes bert-yes rand |
| 30 | + self.mode = mode |
| 31 | + self.vocab = None |
| 32 | + self.dataset_name = dataset_name |
| 33 | + self.vocab_size = 1000 |
| 34 | + self.embedding_dim = 100 |
| 35 | + self.embedding = None |
| 36 | + # Bert rand mode need padding_idx, Bert/roberta does not need |
| 37 | + self.load_embeddings() |
| 38 | + self.conv = nn.ModuleList([nn.Conv1d(in_channels=self.embedding_dim, |
| 39 | + out_channels=num_filters, |
| 40 | + kernel_size=k, stride=1) for k in kernel_sizes]) |
| 41 | + self.dropout = nn.Dropout(d_prob) |
| 42 | + self.fc = nn.Linear(len(kernel_sizes) * num_filters, num_classes) |
| 43 | + |
| 44 | + def forward(self, x): |
| 45 | + # batch_size, sequence_length = x.shape |
| 46 | + # b*l*dim->b*dim*l |
| 47 | + x = self.embedding(x).transpose(1, 2) |
| 48 | + x = [F.relu(conv(x)) for conv in self.conv] |
| 49 | + x = [F.max_pool1d(c, c.size(-1)).squeeze(dim=-1) for c in x] |
| 50 | + x = torch.cat(x, dim=1) |
| 51 | + x = self.fc(self.dropout(x)) |
| 52 | + return x.squeeze() |
| 53 | + |
| 54 | + def load_embeddings(self): |
| 55 | + if self.mode == 'rand': |
| 56 | + if self.dataset_name == "Pheme": |
| 57 | + path_saved = "/data/sunhao/robustfakenews/dataset/vocab/pheme_vocab.pt" |
| 58 | + elif self.dataset_name == "Twitter": |
| 59 | + path_saved = "/data/sunhao/robustfakenews/dataset/vocab/twitter_vocab.pt" |
| 60 | + else: |
| 61 | + print('When Randomly initialized embeddings, the vocabulary is wrong') |
| 62 | + exit(0) |
| 63 | + vocab = torch.load(path_saved) |
| 64 | + self.vocab_size = len(vocab) |
| 65 | + self.embedding_dim = 100 |
| 66 | + self.embedding = nn.Embedding(self.vocab_size, self.embedding_dim, padding_idx=vocab['<pad>']) |
| 67 | + self.embedding.weight.data.requires_grad = True |
| 68 | + del vocab |
| 69 | + print('Randomly initialized embeddings are used.') |
| 70 | + else: |
| 71 | + # /data/sunhao/robustfakenews/pretrain_model |
| 72 | + mode = self.mode.split("-") |
| 73 | + assert len(mode) == 2 |
| 74 | + path_saved = "/data/sunhao/robustfakenews/pretrain_model" |
| 75 | + if mode[0] == 'roberta': |
| 76 | + config = AutoConfig.from_pretrained(os.path.join(path_saved, "roberta")) |
| 77 | + roberta = AutoModel.from_pretrained(os.path.join(path_saved, "roberta"), config=config) |
| 78 | + weight = roberta.get_input_embeddings().weight |
| 79 | + self.vocab_size = weight.shape[0] |
| 80 | + self.embedding_dim = weight.shape[1] |
| 81 | + self.embedding = nn.Embedding(self.vocab_size, self.embedding_dim).from_pretrained( |
| 82 | + weight) |
| 83 | + # self.embedding.weight.data.copy_(roberta.get_input_embeddings().weight) |
| 84 | + del roberta, config, weight |
| 85 | + elif mode[0] == 'bert': |
| 86 | + config = AutoConfig.from_pretrained(os.path.join(path_saved, "bert")) |
| 87 | + bert = AutoModel.from_pretrained(os.path.join(path_saved, "bert"), config=config) |
| 88 | + weight = bert.get_input_embeddings().weight |
| 89 | + self.vocab_size = weight.shape[0] |
| 90 | + self.embedding_dim = weight.shape[1] |
| 91 | + self.embedding = nn.Embedding(self.vocab_size, self.embedding_dim).from_pretrained(weight) |
| 92 | + del bert, config, weight |
| 93 | + |
| 94 | + else: |
| 95 | + raise ValueError('Unexpected value of mode. Please choose from roberta-non, roberta-yes, rand.') |
| 96 | + |
| 97 | + if mode[1] == 'non': |
| 98 | + self.embedding.weight.data.requires_grad = False |
| 99 | + print('Loaded pretrained embeddings, weights are not trainable.') |
| 100 | + |
| 101 | + elif mode[1] == 'yes': |
| 102 | + self.embedding.weight.data.requires_grad = True |
| 103 | + print('Loaded pretrained embeddings, weights are trainable.') |
| 104 | + |
| 105 | + else: |
| 106 | + raise ValueError('Unexpected value of mode[1].') |
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