diff --git a/Seq2seq/seq2seq.py b/Seq2seq/seq2seq.py index eade343..9208a35 100644 --- a/Seq2seq/seq2seq.py +++ b/Seq2seq/seq2seq.py @@ -1,263 +1,178 @@ -import torch -import torch.nn as nn -import torch.optim as optim -import random -import re -import unicodedata -from torchtext.data.metrics import bleu_score +import numpy as np +import keras +from nltk.translate.bleu_score import corpus_bleu -device = torch.device('cuda' if torch.cuda.is_available() else 'cpu') +# Configuration +batch_size = 64 +epochs = 350 +latent_dim = 256 +num_samples = 50000 +data_path = "fra.txt" -# Data preparation -def unicode_to_ascii(s): - return ''.join(c for c in unicodedata.normalize('NFD', s) - if unicodedata.category(c) != 'Mn') +# Preparing data +input_texts = [] +target_texts = [] +input_characters = set() +target_characters = set() +with open(data_path, "r", encoding="utf-8") as f: + lines = f.read().split("\n") +for line in lines[: min(num_samples, len(lines) - 1)]: + input_text, target_text, _ = line.split("\t") + target_text = "\t" + target_text + "\n" + input_texts.append(input_text) + target_texts.append(target_text) + for char in input_text: + if char not in input_characters: + input_characters.add(char) + for char in target_text: + if char not in target_characters: + target_characters.add(char) -def preprocess_sentence(w): - w = unicode_to_ascii(w.lower().strip()) - w = re.sub(r"([?.!,¿])", r" \1 ", w) - w = re.sub(r'[" "]+', " ", w) - w = re.sub(r"[^a-zA-Z?.!,¿]+", " ", w) - w = w.strip() - return w +input_characters = sorted(list(input_characters)) +target_characters = sorted(list(target_characters)) +num_encoder_tokens = len(input_characters) +num_decoder_tokens = len(target_characters) +max_encoder_seq_length = max([len(txt) for txt in input_texts]) +max_decoder_seq_length = max([len(txt) for txt in target_texts]) -def read_langs(lang1, lang2, path): - lines = open(path, encoding='utf-8').read().strip().split('\n') - pairs = [] - for line in lines: - parts = line.split('\t') - if len(parts) >= 2: - pairs.append([preprocess_sentence(parts[0]), preprocess_sentence(parts[1])]) - return pairs +print("Number of samples:", len(input_texts)) +print("Number of unique input tokens:", num_encoder_tokens) +print("Number of unique output tokens:", num_decoder_tokens) +print("Max sequence length for inputs:", max_encoder_seq_length) +print("Max sequence length for outputs:", max_decoder_seq_length) -data_path = 'fra.txt' -pairs = read_langs('eng', 'fra', data_path) +input_token_index = dict([(char, i) for i, char in enumerate(input_characters)]) +target_token_index = dict([(char, i) for i, char in enumerate(target_characters)]) -# Vocabulary class -class Vocabulary: - def __init__(self): - self.word2index = {} - self.index2word = {} - self.word2count = {} - self.n_words = 0 - self.add_word('') - self.add_word('') +encoder_input_data = np.zeros( + (len(input_texts), max_encoder_seq_length, num_encoder_tokens), + dtype="float32", +) +decoder_input_data = np.zeros( + (len(input_texts), max_decoder_seq_length, num_decoder_tokens), + dtype="float32", +) +decoder_target_data = np.zeros( + (len(input_texts), max_decoder_seq_length, num_decoder_tokens), + dtype="float32", +) - def add_sentence(self, sentence): - for word in sentence.split(' '): - self.add_word(word) +for i, (input_text, target_text) in enumerate(zip(input_texts, target_texts)): + for t, char in enumerate(input_text): + encoder_input_data[i, t, input_token_index[char]] = 1.0 + encoder_input_data[i, t + 1 :, input_token_index[" "]] = 1.0 + for t, char in enumerate(target_text): + decoder_input_data[i, t, target_token_index[char]] = 1.0 + if t > 0: + decoder_target_data[i, t - 1, target_token_index[char]] = 1.0 + decoder_input_data[i, t + 1 :, target_token_index[" "]] = 1.0 + decoder_target_data[i, t:, target_token_index[" "]] = 1.0 - def add_word(self, word): - if word not in self.word2index: - self.word2index[word] = self.n_words - self.index2word[self.n_words] = word - self.word2count[word] = 1 - self.n_words += 1 - else: - self.word2count[word] += 1 +# Creating model +encoder_inputs = keras.Input(shape=(None, num_encoder_tokens)) +encoder = keras.layers.LSTM(latent_dim, return_state=True) +encoder_outputs, state_h, state_c = encoder(encoder_inputs) +encoder_states = [state_h, state_c] - def lookup(self, word): - return self.word2index.get(word, self.word2index['']) +decoder_inputs = keras.Input(shape=(None, num_decoder_tokens)) +decoder_lstm = keras.layers.LSTM(latent_dim, return_sequences=True, return_state=True) +decoder_outputs, _, _ = decoder_lstm(decoder_inputs, initial_state=encoder_states) +decoder_dense = keras.layers.Dense(num_decoder_tokens, activation="softmax") +decoder_outputs = decoder_dense(decoder_outputs) -eng_vocab = Vocabulary() -fra_vocab = Vocabulary() +model = keras.Model([encoder_inputs, decoder_inputs], decoder_outputs) -for pair in pairs: - eng_vocab.add_sentence(pair[0]) - fra_vocab.add_sentence(pair[1]) +# Creating the training model +model.compile( + optimizer="rmsprop", loss="categorical_crossentropy", metrics=["accuracy"] +) +model.fit( + [encoder_input_data, decoder_input_data], + decoder_target_data, + batch_size=batch_size, + epochs=epochs, + validation_split=0.2, +) +model.save("s2s_model.keras") -# Seq2Seq Model with Attention -class Encoder(nn.Module): - def __init__(self, input_dim, emb_dim, hid_dim, n_layers, dropout): - super().__init__() - self.embedding = nn.Embedding(input_dim, emb_dim) - self.rnn = nn.GRU(emb_dim, hid_dim, n_layers, dropout=dropout, bidirectional=True) - self.fc = nn.Linear(hid_dim * 2, hid_dim) - self.dropout = nn.Dropout(dropout) +# Sampling +model = keras.models.load_model("s2s_model.keras") - def forward(self, src): - embedded = self.dropout(self.embedding(src)) - outputs, hidden = self.rnn(embedded) - # Sum bidirectional outputs - hidden = torch.tanh(self.fc(torch.cat((hidden[-2,:,:], hidden[-1,:,:]), dim=1))) - return outputs, hidden +encoder_inputs = model.input[0] +encoder_outputs, state_h_enc, state_c_enc = model.layers[2].output +encoder_states = [state_h_enc, state_c_enc] +encoder_model = keras.Model(encoder_inputs, encoder_states) -class Attention(nn.Module): - def __init__(self, hid_dim): - super().__init__() - self.attn = nn.Linear(hid_dim * 3, hid_dim) - self.v = nn.Linear(hid_dim, 1, bias=False) +decoder_inputs = model.input[1] +decoder_state_input_h = keras.Input(shape=(latent_dim,)) +decoder_state_input_c = keras.Input(shape=(latent_dim,)) +decoder_states_inputs = [decoder_state_input_h, decoder_state_input_c] +decoder_lstm = model.layers[3] +decoder_outputs, state_h_dec, state_c_dec = decoder_lstm( + decoder_inputs, initial_state=decoder_states_inputs +) +decoder_states = [state_h_dec, state_c_dec] +decoder_dense = model.layers[4] +decoder_outputs = decoder_dense(decoder_outputs) +decoder_model = keras.Model( + [decoder_inputs] + decoder_states_inputs, [decoder_outputs] + decoder_states +) - def forward(self, hidden, encoder_outputs): - # hidden = [batch size, hid dim] - # encoder_outputs = [src len, batch size, hid dim * 2] - src_len = encoder_outputs.shape[0] - hidden = hidden.unsqueeze(1).expand(-1, src_len, -1) - encoder_outputs = encoder_outputs.permute(1, 0, 2) - # hidden = [batch size, src len, hid dim] - # encoder_outputs = [batch size, src len, hid dim * 2] - energy = torch.tanh(self.attn(torch.cat((hidden, encoder_outputs), dim=2))) - # energy = [batch size, src len, hid dim] - attention = self.v(energy).squeeze(2) - # attention = [batch size, src len] - return torch.softmax(attention, dim=1) +reverse_input_char_index = dict((i, char) for char, i in input_token_index.items()) +reverse_target_char_index = dict((i, char) for char, i in target_token_index.items()) -class Decoder(nn.Module): - def __init__(self, output_dim, emb_dim, hid_dim, n_layers, dropout, attention): - super().__init__() - self.output_dim = output_dim - self.attention = attention - self.embedding = nn.Embedding(output_dim, emb_dim) - self.rnn = nn.GRU(hid_dim * 2 + emb_dim, hid_dim, n_layers, dropout=dropout) - self.fc_out = nn.Linear(hid_dim * 3 + emb_dim, output_dim) - self.dropout = nn.Dropout(dropout) +def decode_sequences(input_seqs): + states_values = encoder_model.predict(input_seqs, verbose=0) + target_seqs = np.zeros((len(input_seqs), 1, num_decoder_tokens)) + target_seqs[:, 0, target_token_index["\t"]] = 1.0 + decoded_sentences = [""] * len(input_seqs) + stop_conditions = np.zeros(len(input_seqs), dtype=bool) - def forward(self, input, hidden, encoder_outputs): - input = input.unsqueeze(0) - embedded = self.dropout(self.embedding(input)) - a = self.attention(hidden[-1], encoder_outputs).unsqueeze(1) - encoder_outputs = encoder_outputs.permute(1, 0, 2) - weighted = torch.bmm(a, encoder_outputs) - rnn_input = torch.cat((embedded, weighted.permute(1, 0, 2)), dim=2) - output, hidden = self.rnn(rnn_input, hidden) - embedded = embedded.squeeze(0) - output = output.squeeze(0) - weighted = weighted.squeeze(1) - prediction = self.fc_out(torch.cat((output, weighted, embedded), dim=1)) - return prediction, hidden + while not np.all(stop_conditions): + output_tokens, h, c = decoder_model.predict( + [target_seqs] + states_values, verbose=0 + ) -class Seq2Seq(nn.Module): - def __init__(self, encoder, decoder, device): - super().__init__() - self.encoder = encoder - self.decoder = decoder - self.device = device + sampled_token_indices = np.argmax(output_tokens[:, -1, :], axis=1) + sampled_chars = [ + reverse_target_char_index[idx] for idx in sampled_token_indices + ] - def forward(self, src, trg, teacher_forcing_ratio=0.5): - trg_len = trg.shape[0] - batch_size = trg.shape[1] - trg_vocab_size = self.decoder.output_dim - outputs = torch.zeros(trg_len, batch_size, trg_vocab_size).to(self.device) - encoder_outputs, hidden = self.encoder(src) - # Initialize hidden state of the decoder with the hidden state of the encoder - hidden = hidden.unsqueeze(0).repeat(self.decoder.rnn.num_layers, 1, 1) - input = trg[0, :] - for t in range(1, trg_len): - output, hidden = self.decoder(input, hidden, encoder_outputs) - outputs[t] = output - top1 = output.argmax(1) - input = trg[t] if random.random() < teacher_forcing_ratio else top1 - return outputs + for i, char in enumerate(sampled_chars): + decoded_sentences[i] += char + if char == "\n" or len(decoded_sentences[i]) > max_decoder_seq_length: + stop_conditions[i] = True -# Training and evaluation functions -def train(model, iterator, optimizer, criterion, clip, print_every=100, max_batches=1000): - model.train() - epoch_loss = 0 - i = 0 # Initialize batch counter - for src, trg in iterator: - if i >= max_batches: # Limit the number of batches processed in each epoch - break - src = src.to(device) - trg = trg.to(device) - optimizer.zero_grad() - output = model(src, trg) - output_dim = output.shape[-1] - output = output[1:].reshape(-1, output_dim) - trg = trg[1:].reshape(-1) - loss = criterion(output, trg) - loss.backward() - torch.nn.utils.clip_grad_norm_(model.parameters(), clip) - optimizer.step() - epoch_loss += loss.item() - - if (i + 1) % print_every == 0: - print(f'Batch {i+1}, Loss: {loss.item():.4f}') - - i += 1 # Increment batch counter + target_seqs = np.zeros((len(input_seqs), 1, num_decoder_tokens)) + for i, token_index in enumerate(sampled_token_indices): + target_seqs[i, 0, token_index] = 1.0 - return epoch_loss / (i if i > 0 else 1) # Avoid division by zero + states_values = [h, c] -def evaluate(model, iterator, criterion): - model.eval() - epoch_loss = 0 - i = 0 # Initialize batch counter - with torch.no_grad(): - for src, trg in iterator: - src = src.to(device) - trg = trg.to(device) - output = model(src, trg, 0) - output_dim = output.shape[-1] - output = output[1:].reshape(-1, output_dim) - trg = trg[1:].reshape(-1) - loss = criterion(output, trg) - epoch_loss += loss.item() - i += 1 # Increment batch counter - return epoch_loss / (i if i > 0 else 1) # Avoid division by zero + return decoded_sentences -# BLEU Score calculation -def calculate_bleu(data, model, src_vocab, trg_vocab): - trgs = [] - pred_trgs = [] - for (src, trg) in data: - src_tensor = torch.tensor([src_vocab.lookup(word) for word in src.split(' ')]).unsqueeze(1).to(device) - trg_tensor = torch.tensor([trg_vocab.lookup(word) for word in trg.split(' ')]).unsqueeze(1).to(device) - with torch.no_grad(): - output = model(src_tensor, trg_tensor, 0) - output_dim = output.shape[-1] - output = output[1:].reshape(-1, output_dim) - output = output.argmax(1) - pred_trg = [trg_vocab.index2word[idx.item()] for idx in output if idx.item() != trg_vocab.word2index['']] - pred_trgs.append(pred_trg) - trgs.append([trg.split(' ')]) - return bleu_score(pred_trgs, trgs) +# BLEU score evaluation +def calculate_bleu_score(input_texts, target_texts, num_samples=500): + input_seqs = np.zeros( + (num_samples, max_encoder_seq_length, num_encoder_tokens), dtype="float32" + ) + for i, input_text in enumerate(input_texts[:num_samples]): + for t, char in enumerate(input_text): + input_seqs[i, t, input_token_index[char]] = 1.0 + input_seqs[i, t + 1 :, input_token_index[" "]] = 1.0 -# Main script -INPUT_DIM = eng_vocab.n_words -OUTPUT_DIM = fra_vocab.n_words -ENC_EMB_DIM = 256 -DEC_EMB_DIM = 256 -HID_DIM = 512 -N_LAYERS = 2 -ENC_DROPOUT = 0.5 -DEC_DROPOUT = 0.5 -BATCH_SIZE = 32 -N_EPOCHS = 7 -CLIP = 1 + decoded_sentences = decode_sequences(input_seqs) -attn = Attention(HID_DIM) -enc = Encoder(INPUT_DIM, ENC_EMB_DIM, HID_DIM, N_LAYERS, ENC_DROPOUT) -dec = Decoder(OUTPUT_DIM, DEC_EMB_DIM, HID_DIM, N_LAYERS, DEC_DROPOUT, attn) + references = [[list(text.strip())] for text in target_texts[:num_samples]] + hypotheses = [list(text.strip()) for text in decoded_sentences] + bleu = corpus_bleu(references, hypotheses) + print("BLEU Score:", bleu) -model = Seq2Seq(enc, dec, device).to(device) -optimizer = optim.Adam(model.parameters()) -criterion = nn.CrossEntropyLoss(ignore_index=fra_vocab.word2index['']) + print("\nExample Translations:") + for i in range(10): + print("Input:", input_texts[i]) + print("Target:", target_texts[i]) + print("Translation:", decoded_sentences[i]) + print() -# Splitting data into train and test sets -train_data = pairs[:int(0.8*len(pairs))] -test_data = pairs[int(0.8*len(pairs)):] - -# Custom DataLoader with padding -def pad_sequence(seq, max_len, pad_value): - seq += [pad_value] * (max_len - len(seq)) - return seq - -def data_generator(data, src_vocab, trg_vocab, batch_size): - for i in range(0, len(data), batch_size): - src_batch = [d[0] for d in data[i:i+batch_size]] - trg_batch = [d[1] for d in data[i:i+batch_size]] - max_src_len = max(len(s.split(' ')) for s in src_batch) - max_trg_len = max(len(s.split(' ')) for s in trg_batch) - src_tensor = torch.tensor([pad_sequence([src_vocab.lookup(word) for word in sentence.split(' ')], max_len=max_src_len, pad_value=src_vocab.word2index['']) for sentence in src_batch], dtype=torch.long).T - trg_tensor = torch.tensor([pad_sequence([trg_vocab.lookup(word) for word in sentence.split(' ')], max_len=max_trg_len, pad_value=trg_vocab.word2index['']) for sentence in trg_batch], dtype=torch.long).T - yield src_tensor, trg_tensor - -for epoch in range(N_EPOCHS): - print(f'Epoch {epoch+1}/{N_EPOCHS}') - train_iterator = data_generator(train_data, eng_vocab, fra_vocab, BATCH_SIZE) - valid_iterator = data_generator(test_data, eng_vocab, fra_vocab, BATCH_SIZE) - train_loss = train(model, train_iterator, optimizer, criterion, CLIP) - valid_loss = evaluate(model, valid_iterator, criterion) - print(f'Epoch {epoch+1:02}, Train Loss: {train_loss:.3f}, Val. Loss: {valid_loss:.3f}') - -bleu = calculate_bleu(test_data, model, eng_vocab, fra_vocab) -print(f'BLEU score = {bleu:.2f}') +calculate_bleu_score(input_texts, target_texts)