tirthadagr8/custom-mbart-large-50

import torch
import torch.nn as nn
from transformers import MBartForConditionalGeneration, MBart50TokenizerFast

class TextRefinementModel(nn.Module):
    def __init__(self, model_name='tirthadagr8/custom-mbart-large-50', max_length=64):
        super(TextRefinementModel, self).__init__()
        self.tokenizer = MBart50TokenizerFast.from_pretrained(model_name)
        self.mbart = MBartForConditionalGeneration.from_pretrained(model_name)
        self.mbart.config.max_length=64
        self.max_length = max_length
        
        # Set the language code for Japanese (ja_XX) or Chinese (zh_CN)
#         self.tokenizer.src_lang = 'ja_XX'  # For Japanese
        # self.tokenizer.src_lang = 'zh_CN'  # Uncomment for Chinese

    def forward(self, input_texts):
        # Tokenize the noisy text inputs
        input_ids = self.tokenizer(input_texts, return_tensors='pt', padding=True, truncation=True, max_length=self.max_length)['input_ids']
        
        # mBART generates output logits
        output_logits = self.mbart(input_ids).logits
        
        return output_logits

    def generate_corrected_text(self, input_texts, temperature=0.7):
        # Tokenize the input noisy text
        input_ids = self.tokenizer(input_texts, return_tensors='pt', padding=True, truncation=True, max_length=self.max_length)['input_ids']
        
        # Generate corrected text using mBART's generate function
        mbart_outputs = self.mbart.generate(input_ids, max_length=self.max_length, temperature=temperature, num_return_sequences=1)
        
        # Decode generated text
        corrected_texts = [self.tokenizer.decode(g, skip_special_tokens=True) for g in mbart_outputs]
        return corrected_texts

# Example usage
model = TextRefinementModel()

noisy_text = ["これは間違ったテキストの例です。", "这是错误的文本示例。"]  # Japanese and Chinese examples
corrected_text = model.generate_corrected_text(noisy_text)

print(f"Corrected Text: {corrected_text}")

For training:

from transformers import AdamW
import torch.nn.functional as F
from tqdm import tqdm
from torch.utils.data import DataLoader
import numpy as np

# Initialize the mBART model and optimizer
model = TextRefinementModel().cuda()
optimizer = AdamW(model.parameters(), lr=5e-5)

batch_size = 16

# Create a custom dataset class
class TextCorrectionDataset(torch.utils.data.Dataset):
    def __init__(self, data, tokenizer, max_length=64):
        self.data = data
        self.tokenizer = tokenizer
        self.max_length = max_length

    def __len__(self):
        return len(self.data)

    def __getitem__(self, idx):
        noisy_text, correct_text = self.data[idx]
        inputs = self.tokenizer(noisy_text, return_tensors='pt', padding='max_length', truncation=True, max_length=self.max_length)
        labels = self.tokenizer(correct_text, return_tensors='pt', padding='max_length', truncation=True, max_length=self.max_length)
        
        # Adjust label tensors for correct shape
        input_ids = inputs['input_ids'].squeeze()  # Remove extra batch dimension
        labels = labels['input_ids'].squeeze()     # Same for labels
        return input_ids, labels

# Create DataLoader with batching
train_dataset = TextCorrectionDataset(train_data, model.tokenizer)
train_loader = DataLoader(train_dataset, batch_size=batch_size, shuffle=True)

# Define training loop with batches
def train_epoch(model, train_loader, optimizer):
    model.train()
    total_loss = []
    step_iter=0
    for input_ids, labels in tqdm(train_loader):
        # Move tensors to model's device
        input_ids = input_ids.to(model.mbart.device)
        labels = labels.to(model.mbart.device)
        
        # Forward pass
        outputs = model.mbart(input_ids=input_ids, labels=labels)
        loss = outputs.loss
        
        # Backpropagation
        optimizer.zero_grad()
        loss.backward()
        optimizer.step()
        
        total_loss.append(loss.item())
        
        if step_iter%100==0:
            print('Loss:',np.mean(total_loss))
        
        step_iter+=1
    return np.mean(total_loss)

# Example training loop
for epoch in range(5):  # Train for 5 epochs (or as needed)
    loss = train_epoch(model, train_loader, optimizer)
    print(f"Epoch {epoch+1}, Loss: {loss:.4f}")