vocab_size = 98635 max_len=200 hidden_dim=32这3段代码啥意思
时间: 2024-03-04 18:50:38 浏览: 20
这三段代码应该是指在构建模型时使用的一些参数。
- `vocab_size = 98635`:这是指模型使用的词汇表(Vocabulary)的大小,也就是模型中可以使用的不同词汇的数量。这个值通常是根据语料库中的词汇数量来确定的。
- `max_len=200`:这是指模型处理的输入文本的最大长度,超过这个长度的部分将会被截断。这个值通常是根据语料库中文本的长度分布来确定的。
- `hidden_dim=32`:这是指模型中隐藏层的维度大小,也就是模型在处理文本时使用的特征的数量。这个值通常是根据实验调整得到的,一般来说,更大的值可以提高模型的表达能力,但会增加模型的复杂度和计算量。
相关问题
写一段transformer代码
### 回答1:
好的,以下是一个简单的 Transformer 代码示例:
```
import tensorflow as tf
class Transformer(tf.keras.Model):
def __init__(self, num_layers, d_model, num_heads, dff, input_vocab_size, target_vocab_size, rate=0.1):
super(Transformer, self).__init__()
self.encoder = Encoder(num_layers, d_model, num_heads, dff, input_vocab_size, rate)
self.decoder = Decoder(num_layers, d_model, num_heads, dff, target_vocab_size, rate)
self.final_layer = tf.keras.layers.Dense(target_vocab_size)
def call(self, inp, tar, training, enc_padding_mask, look_ahead_mask, dec_padding_mask):
enc_output = self.encoder(inp, training, enc_padding_mask)
dec_output, attention_weights = self.decoder(
tar, enc_output, training, look_ahead_mask, dec_padding_mask)
final_output = self.final_layer(dec_output)
return final_output, attention_weights
class Encoder(tf.keras.layers.Layer):
def __init__(self, num_layers, d_model, num_heads, dff, input_vocab_size, rate=0.1):
super(Encoder, self).__init__()
self.d_model = d_model
self.num_layers = num_layers
self.embedding = tf.keras.layers.Embedding(input_vocab_size, d_model)
self.pos_encoding = positional_encoding(input_vocab_size, self.d_model)
self.enc_layers = [EncoderLayer(d_model, num_heads, dff, rate)
for _ in range(num_layers)]
self.dropout = tf.keras.layers.Dropout(rate)
def call(self, x, training, mask):
seq_len = tf.shape(x)[1]
# adding embedding and position encoding.
x = self.embedding(x) # (batch_size, input_seq_len, d_model)
x *= tf.math.sqrt(tf.cast(self.d_model, tf.float32))
x += self.pos_encoding[:, :seq_len, :]
x = self.dropout(x, training=training)
for i in range(self.num_layers):
x = self.enc_layers[i](x, training, mask)
return x
class EncoderLayer(tf.keras.layers.Layer):
def __init__(self, d_model, num_heads, dff, rate=0.1):
super(EncoderLayer, self).__init__()
self.mha = MultiHeadAttention(d_model, num_heads)
self.ffn = point_wise_feed_forward_network(d_model, dff)
self.layernorm1 = tf.keras.layers.LayerNormalization(epsilon=1e-6)
self.layernorm2 = tf.keras.layers.LayerNormalization(epsilon=1e-6)
self.dropout1 = tf.keras.layers.Dropout(rate)
self.dropout2 = tf.keras.layers.Dropout(rate)
def call(self, x, training, mask):
attn_output, _ = self.mha(x, x, x, mask)
attn_output = self.dropout1(attn_output, training=training)
out1 = self.layernorm1(x + attn_output)
ffn_output = self.ffn(out1)
ffn_output = self.dropout2(ffn_output, training=training)
out2 = self.layernorm2(out1 + ffn_output)
return out2
class Decoder(tf.keras.layers.Layer):
def __init__(self, num_layers, d_model, num_heads, dff, target_vocab_size, rate=0.1):
super(Decoder, self).__init__()
self.d_model = d_model
self.num_layers = num_layers
self.embedding = tf.keras.layers
### 回答2:
Transformer是一种用于自然语言处理的深度学习模型。以下是一个使用Python编写的简单Transformer代码段,用于进行文本分类任务:
```python
import torch
import torch.nn as nn
import torch.optim as optim
class Transformer(nn.Module):
def __init__(self, input_dim, output_dim, hidden_dim, num_layers, num_heads):
super(Transformer, self).__init__()
self.embedding = nn.Embedding(input_dim, hidden_dim)
self.positional_encoding = PositionalEncoding(hidden_dim)
self.transformer_encoder_layer = nn.TransformerEncoderLayer(hidden_dim, num_heads)
self.transformer_encoder = nn.TransformerEncoder(self.transformer_encoder_layer, num_layers)
self.fc = nn.Linear(hidden_dim, output_dim)
def forward(self, x):
embedded = self.embedding(x)
encoded = self.positional_encoding(embedded)
transformed = self.transformer_encoder(encoded)
pooled = torch.mean(transformed, dim=1)
output = self.fc(pooled)
return output
class PositionalEncoding(nn.Module):
def __init__(self, hidden_dim, max_seq_len=300):
super(PositionalEncoding, self).__init__()
self.hidden_dim = hidden_dim
self.dropout = nn.Dropout(p=0.1)
pe = torch.zeros(max_seq_len, hidden_dim)
position = torch.arange(0, max_seq_len).unsqueeze(1)
div_term = torch.exp(torch.arange(0, hidden_dim, 2) * -(math.log(10000.0) / hidden_dim))
pe[:, 0::2] = torch.sin(position * div_term)
pe[:, 1::2] = torch.cos(position * div_term)
self.register_buffer('pe', pe.unsqueeze(0))
def forward(self, x):
x = x * math.sqrt(self.hidden_dim)
x = x + self.pe[:, :x.size(1)]
x = self.dropout(x)
return x
```
以上代码定义了一个Transformer模型类,包括一个词嵌入层、位置编码层、Transformer编码层和一个全连接层。其中,位置编码层使用来自论文《Attention is All You Need》中提出的方法,用于为序列中的词汇位置添加信息。模型的前向传播过程首先对输入的文本进行词嵌入,然后进行位置编码,接着使用Transformer编码层进行特征提取和表示学习,将输出进行平均池化后再通过全连接层进行分类预测。这段代码可以用于文本分类任务中,输入是一个整数序列,输出是每个类别的预测概率。
### 回答3:
Transformer是一种深度学习模型架构,适用于自然语言处理任务,例如机器翻译、文本生成等。下面是一个简单的Transformer代码示例:
```python
import torch
import torch.nn as nn
import torch.nn.functional as F
class TransformerEncoder(nn.Module):
def __init__(self, input_size, hidden_size, num_layers, num_heads):
super(TransformerEncoder, self).__init__()
self.embedding = nn.Embedding(input_size, hidden_size)
self.position_encoding = PositionalEncoding(hidden_size)
self.encoder_layer = TransformerEncoderLayer(hidden_size, num_heads)
def forward(self, inputs):
embeddings = self.embedding(inputs)
encoded = self.position_encoding(embeddings)
output = self.encoder_layer(encoded)
return output
class PositionalEncoding(nn.Module):
def __init__(self, hidden_size, max_sequence_length=1000):
super(PositionalEncoding, self).__init__()
position_encoding = torch.zeros(max_sequence_length, hidden_size)
position = torch.arange(0, max_sequence_length, dtype=torch.float).unsqueeze(1)
div_term = torch.exp(torch.arange(0, hidden_size, 2).float() * (-math.log(10000.0) / hidden_size))
position_encoding[:, 0::2] = torch.sin(position * div_term)
position_encoding[:, 1::2] = torch.cos(position * div_term)
self.register_buffer('position_encoding', position_encoding)
def forward(self, inputs):
seq_length = inputs.size(1)
position_encoding = self.position_encoding[:seq_length, :]
return inputs + position_encoding
class TransformerEncoderLayer(nn.Module):
def __init__(self, hidden_size, num_heads, dropout=0.1):
super(TransformerEncoderLayer, self).__init__()
self.self_attention = MultiHeadAttention(hidden_size, num_heads)
self.feed_forward = FeedForward(hidden_size)
self.dropout = nn.Dropout(dropout)
def forward(self, inputs):
attended = self.self_attention(inputs)
attended = self.dropout(attented)
output = attended + inputs
output = self.feed_forward(output)
output = self.dropout(output)
return output
class MultiHeadAttention(nn.Module):
def __init__(self, hidden_size, num_heads):
super(MultiHeadAttention, self).__init__()
self.hidden_size = hidden_size
self.num_heads = num_heads
self.head_size = hidden_size // num_heads
self.W_q = nn.Linear(hidden_size, hidden_size)
self.W_k = nn.Linear(hidden_size, hidden_size)
self.W_v = nn.Linear(hidden_size, hidden_size)
self.W_o = nn.Linear(hidden_size, hidden_size)
def forward(self, inputs):
batch_size, seq_length, _ = inputs.size()
query = self.W_q(inputs)
key = self.W_k(inputs)
value = self.W_v(inputs)
query = query.view(batch_size, seq_length, self.num_heads, self.head_size).transpose(1, 2)
key = key.view(batch_size, seq_length, self.num_heads, self.head_size).transpose(1, 2)
value = value.view(batch_size, seq_length, self.num_heads, self.head_size).transpose(1, 2)
attention_scores = torch.matmul(query, key.transpose(-1, -2)) / math.sqrt(self.head_size)
attention_probs = F.softmax(attention_scores, dim=-1)
attended = torch.matmul(attention_probs, value).transpose(1, 2).contiguous().view(batch_size, seq_length, self.hidden_size)
output = self.W_o(attended)
return output
class FeedForward(nn.Module):
def __init__(self, hidden_size, dropout=0.1):
super(FeedForward, self).__init__()
self.linear1 = nn.Linear(hidden_size, 4 * hidden_size)
self.linear2 = nn.Linear(4 * hidden_size, hidden_size)
self.dropout = nn.Dropout(dropout)
def forward(self, inputs):
output = self.linear1(inputs)
output = F.relu(output)
output = self.dropout(output)
output = self.linear2(output)
return output
```
以上是一个简单的Transformer模型代码示例,包括了TransformerEncoder、PositionalEncoding、TransformerEncoderLayer、MultiHeadAttention和FeedForward等模块的实现。这段代码可以作为一个Transformer模型的基本框架,但是其中的具体实现可能需要根据具体任务需求进行调整和优化。
写一段NER任务的完整代码
下面是一个基于PyTorch的NER任务代码示例,其中使用了BiLSTM-CRF模型:
```python
import torch
import torch.nn as nn
import torch.optim as optim
class BiLSTM_CRF(nn.Module):
def __init__(self, vocab_size, tag_to_ix, embedding_dim, hidden_dim):
super(BiLSTM_CRF, self).__init__()
self.embedding_dim = embedding_dim
self.hidden_dim = hidden_dim
self.vocab_size = vocab_size
self.tag_to_ix = tag_to_ix
self.tagset_size = len(tag_to_ix)
self.word_embeddings = nn.Embedding(vocab_size, embedding_dim)
self.lstm = nn.LSTM(embedding_dim, hidden_dim // 2,
num_layers=1, bidirectional=True)
self.hidden2tag = nn.Linear(hidden_dim, self.tagset_size)
self.transitions = nn.Parameter(
torch.randn(self.tagset_size, self.tagset_size))
self.transitions.data[tag_to_ix[START_TAG], :] = -10000
self.transitions.data[:, tag_to_ix[STOP_TAG]] = -10000
self.hidden = self.init_hidden()
def init_hidden(self):
return (torch.randn(2, 1, self.hidden_dim // 2),
torch.randn(2, 1, self.hidden_dim // 2))
def _forward_alg(self, feats):
init_alphas = torch.full((1, self.tagset_size), -10000.)
init_alphas[0][self.tag_to_ix[START_TAG]] = 0.
forward_var = init_alphas
for feat in feats:
alphas_t = []
for next_tag in range(self.tagset_size):
emit_score = feat[next_tag].view(
1, -1).expand(1, self.tagset_size)
trans_score = self.transitions[next_tag].view(1, -1)
next_tag_var = forward_var + trans_score + emit_score
alphas_t.append(torch.logsumexp(next_tag_var, dim=1).view(1))
forward_var = torch.cat(alphas_t).view(1, -1)
terminal_var = forward_var + self.transitions[self.tag_to_ix[STOP_TAG]]
alpha = torch.logsumexp(terminal_var, dim=1)[0]
return alpha
def _get_lstm_features(self, sentence):
self.hidden = self.init_hidden()
embeds = self.word_embeddings(sentence).view(len(sentence), 1, -1)
lstm_out, self.hidden = self.lstm(embeds, self.hidden)
lstm_out = lstm_out.view(len(sentence), self.hidden_dim)
lstm_feats = self.hidden2tag(lstm_out)
return lstm_feats
def _score_sentence(self, feats, tags):
score = torch.zeros(1)
tags = torch.cat([torch.tensor([self.tag_to_ix[START_TAG]], dtype=torch.long), tags])
for i, feat in enumerate(feats):
score = score + \
self.transitions[tags[i+1], tags[i]] + feat[tags[i+1]]
score = score + self.transitions[self.tag_to_ix[STOP_TAG], tags[-1]]
return score
def _viterbi_decode(self, feats):
backpointers = []
init_vvars = torch.full((1, self.tagset_size), -10000.)
init_vvars[0][self.tag_to_ix[START_TAG]] = 0
forward_var = init_vvars
for feat in feats:
bptrs_t = []
viterbivars_t = []
for next_tag in range(self.tagset_size):
next_tag_var = forward_var + self.transitions[next_tag]
best_tag_id = argmax(next_tag_var)
bptrs_t.append(best_tag_id)
viterbivars_t.append(next_tag_var[0][best_tag_id].view(1))
forward_var = (torch.cat(viterbivars_t) + feat).view(1, -1)
backpointers.append(bptrs_t)
terminal_var = forward_var + \
self.transitions[self.tag_to_ix[STOP_TAG]]
best_tag_id = argmax(terminal_var)
path_score = terminal_var[0][best_tag_id]
best_path = [best_tag_id]
for bptrs_t in reversed(backpointers):
best_tag_id = bptrs_t[best_tag_id]
best_path.append(best_tag_id)
start = best_path.pop()
assert start == self.tag_to_ix[START_TAG]
best_path.reverse()
return path_score, best_path
def neg_log_likelihood(self, sentence, tags):
lstm_feats = self._get_lstm_features(sentence)
forward_score = self._forward_alg(lstm_feats)
gold_score = self._score_sentence(lstm_feats, tags)
return forward_score - gold_score
def forward(self, sentence):
lstm_feats = self._get_lstm_features(sentence)
score, tag_seq = self._viterbi_decode(lstm_feats)
return score, tag_seq
START_TAG = "<START>"
STOP_TAG = "<STOP>"
EMBEDDING_DIM = 5
HIDDEN_DIM = 4
training_data = [(
"the wall street journal reported today that apple corporation made money".split(),
"B I I I O O O B I O O".split()
), (
"georgia tech is a university in georgia".split(),
"B I O O O O B".split()
)]
word_to_ix = {}
for sentence, tags in training_data:
for word in sentence:
if word not in word_to_ix:
word_to_ix[word] = len(word_to_ix)
tag_to_ix = {"B": 0, "I": 1, "O": 2, START_TAG: 3, STOP_TAG: 4}
model = BiLSTM_CRF(len(word_to_ix), tag_to_ix, EMBEDDING_DIM, HIDDEN_DIM)
optimizer = optim.SGD(model.parameters(), lr=0.01, weight_decay=1e-4)
for epoch in range(300):
for sentence, tags in training_data:
model.zero_grad()
sentence_in = prepare_sequence(sentence, word_to_ix)
targets = torch.tensor([tag_to_ix[t] for t in tags], dtype=torch.long)
loss = model.neg_log_likelihood(sentence_in, targets)
loss.backward()
optimizer.step()
with torch.no_grad():
precheck_sent = prepare_sequence(training_data[0][0], word_to_ix)
print(model(precheck_sent))
```
这份代码实现了一个简单的NER任务的训练和预测,其中BiLSTM-CRF模型结合了BiLSTM和CRF两种技术,用于标注每个单词的实体类型。可以通过调整模型超参数和优化器参数来改进模型性能。