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LSTM Chatbot

Complete Documentation & Project Details for Sequence-to-Sequence & Conversational AI

Project Description

This project implements an LSTM-based sequence-to-sequence chatbot system for conversational AI. The encoder-decoder architecture with attention mechanism processes input sequences and generates contextually relevant responses, making it excellent for multi-turn conversations and natural dialogue. The system includes beam search decoding, conversation history management, temperature sampling, and advanced features like attention visualization, data augmentation, and comprehensive evaluation.

The LSTM chatbot uses encoder-decoder architecture with Bahdanau attention mechanism. The encoder processes input sequences using LSTM layers, while the decoder generates responses with attention to relevant input parts. The implementation provides complete TensorFlow and Keras support, comprehensive training pipeline, REST API server, evaluation metrics, and deployment tools for conversational AI applications.

Project Screenshots

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LSTM Chatbot

Core Features

LSTM Encoder-Decoder

  • LSTM encoder-decoder architecture
  • Sequence-to-sequence modeling
  • Long-term dependency handling
  • Context-aware response generation
  • Natural language understanding

Attention Mechanism

  • Bahdanau attention mechanism
  • Focus on relevant input parts
  • Improved context understanding
  • Attention weight visualization
  • Input-output alignment

Beam Search Decoding

  • Beam search algorithm
  • Multiple candidate exploration
  • Configurable beam width
  • Improved response quality
  • Better sequence selection

Conversation History

  • Multi-turn conversation support
  • Automatic context management
  • Save/load conversation history
  • Configurable history length
  • Context-aware responses

Evaluation Metrics

  • BLEU score calculation
  • Word Error Rate (WER)
  • Perplexity calculation
  • Sample-based evaluation
  • Comprehensive metrics

REST API Server

  • Flask-based API
  • Chat and history endpoints
  • CORS enabled
  • Export functionality
  • Production-ready

Advanced Features

Attention Visualization

  • Attention weight visualization
  • Model interpretability
  • Input-output alignment
  • Visual attention maps
  • Heatmap generation

Data Augmentation

  • Random insertion
  • Random deletion
  • Word swapping
  • Synonym replacement

Temperature Sampling

  • Temperature-controlled sampling
  • Configurable randomness
  • Balanced vs creative responses
  • Fine-tuned output control

Training Visualization

  • Loss curve visualization
  • Accuracy tracking
  • Learning rate monitoring
  • Overfitting detection
  • Training history plots

REST API Endpoints

Endpoint Method Description Request Body Response
/chat POST Main chat interface {"message": "text"} Generated response
/history GET Get conversation history ?num=5 (optional) Conversation history
/history POST Save conversation history {"filepath": "path"} Success message
/clear POST Clear conversation history N/A Success message
/export POST Export chat log {"filepath": "path"} Success message
/health GET Health check N/A Server status

Technologies Used

This LSTM chatbot project is built using modern deep learning and web technologies. The core implementation uses Python as the primary programming language, TensorFlow and Keras for deep learning operations, and PyTorch for additional model support. The project includes an LSTM encoder-decoder architecture with Bahdanau attention mechanism for sequence-to-sequence modeling. The project includes a Flask-based REST API for web integration, Jupyter Notebook support for interactive development and demonstrations, and comprehensive evaluation metrics for assessing model performance.

The LSTM model uses sequence-to-sequence architecture with encoder-decoder design, enabling the model to process input sequences and generate contextually relevant responses. The system supports beam search decoding for better response quality, conversation history for multi-turn dialogue, and temperature sampling for controlling response randomness, making it suitable for various conversational AI applications.

Python 3.8+ TensorFlow 2.13+ Keras LSTM Seq2Seq Attention Conversational AI Jupyter Notebook Flask 2.3+ Evaluation Metrics

Installation & Usage

Installation

Install all required dependencies for the LSTM chatbot project:

# Install all requirements pip install -r requirements.txt # The LSTM model will be trained on your data # Prepare conversation data in data/conversations.txt

Quick Setup

Set up the project structure and verify installation:

# Run quick setup script python quick_start.py setup # Test imports python quick_start.py test-imports # Run quick test python quick_start.py quick-test

Training the Model

Train the LSTM model on your conversation dataset:

# Prepare data in data/conversations.txt # Format: "input|output" (one conversation per line) # Basic training python src/train.py # Or use Jupyter notebook jupyter notebook notebooks/02_model_training.ipynb # Training parameters can be configured in: # - src/model.py (model architecture) # - src/train.py (training loop)

Interactive Chatbot

Run the chatbot in interactive mode for conversations:

# Basic chatbot python demo.py # Enhanced chatbot with beam search and history python demo_enhanced.py # Or use Jupyter notebook jupyter notebook notebooks/03_chatbot_inference.ipynb # Enhanced chatbot with Python from src.chatbot_enhanced import load_enhanced_chatbot chatbot = load_enhanced_chatbot( use_beam_search=True, beam_width=5, use_history=True, max_history=10 ) response = chatbot.chat("Hello!")

REST API Server

Start the Flask API server for web integration:

# Start API server (default port 5000) python api_server.py # API will be available at http://localhost:5000 # Example API calls: # POST /chat - {"message": "Hello"} # GET /history - Get conversation history # GET /history?num=5 - Get last 5 exchanges # POST /history - {"filepath": "chat_history.json"} - Save history # POST /clear - Clear conversation history # POST /export - {"filepath": "chat_log.txt"} - Export chat log # GET /health - Check API health

Model Evaluation

Evaluate the trained model performance:

# Evaluate trained model python src/evaluate_model.py # Or use evaluation module from src.evaluation import evaluate_model results = evaluate_model(model, test_data, processor) print(f"BLEU Score: {results['bleu_score']}") print(f"Word Error Rate: {results['wer']}") print(f"Perplexity: {results['perplexity']}")

Evaluation Metrics

Evaluate chatbot responses using comprehensive metrics:

from src.evaluation import ( calculate_bleu_score, calculate_wer, calculate_perplexity ) # BLEU Score reference = "hello how are you".split() candidate = "hello how are you doing".split() bleu = calculate_bleu_score(reference, candidate) # Word Error Rate (WER) wer = calculate_wer(reference, candidate) # Perplexity perplexity = calculate_perplexity(model, test_data) # Print results print(f"BLEU Score: {bleu:.4f}") print(f"Word Error Rate: {wer:.4f}") print(f"Perplexity: {perplexity:.4f}")

Metric Descriptions:

  • BLEU Score: Measures n-gram precision between reference and candidate text
  • Word Error Rate (WER): Measures edit distance between reference and candidate
  • Perplexity: Measures how well the model predicts the next word in sequence

Attention Visualization

Visualize attention weights to understand model behavior:

from src.visualization import plot_attention_weights # After generating a response, visualize attention plot_attention_weights( attention_weights, input_tokens, output_tokens, save_path='attention.png' ) # This creates a heatmap showing which input words # the model focuses on when generating each output word

Export Chat Logs

Export conversation history to various formats:

# Using enhanced chatbot from src.chatbot_enhanced import load_enhanced_chatbot chatbot = load_enhanced_chatbot(use_history=True) # Save history chatbot.save_history('chat_history.json') # Export chat log chatbot.export_chat_log('chat_log.txt') # Or use API endpoint # POST /export - {"filepath": "chat_log.txt"}

Jupyter Notebook

Open the interactive Jupyter notebooks for demonstrations:

# Data preprocessing notebook jupyter notebook notebooks/01_data_preprocessing.ipynb # Model training notebook jupyter notebook notebooks/02_model_training.ipynb # Chatbot inference notebook jupyter notebook notebooks/03_chatbot_inference.ipynb # Or use JupyterLab jupyter lab notebooks/

Project Structure

lstm-chatbot/
├── README.md # Main documentation
├── requirements.txt # Python dependencies
├── setup.py # Package setup
├── LICENSE # License file
├── PROJECT_INFO.md # Project overview
├── FEATURES.md # Features documentation
│
├── Core Modules (src/)
│ ├── data_processing.py # Data preprocessing
│ ├── model.py # LSTM model architecture
│ ├── attention.py # Attention mechanism
│ ├── train.py # Training script
│ ├── chatbot.py # Basic chatbot
│ ├── chatbot_enhanced.py # Enhanced chatbot
│ ├── beam_search.py # Beam search decoding
│ ├── conversation_history.py # History management
│ ├── evaluation.py # Evaluation metrics
│ ├── evaluate_model.py # Model evaluation
│ ├── visualization.py # Visualization utilities
│ └── data_augmentation.py # Data augmentation
│
├── API & Services
│ ├── api_server.py # Flask web API
│ └── index.html # Web interface
│
├── Data
│ └── conversations.txt # Training data (input|output)
│
├── Models
│ └── (trained model checkpoints)
│
├── Notebooks
│ ├── 01_data_preprocessing.ipynb # Data preprocessing
│ ├── 02_model_training.ipynb # Model training
│ └── 03_chatbot_inference.ipynb # Chatbot inference
│
├── Demo Scripts
│ ├── demo.py # Basic demo
│ └── demo_enhanced.py # Enhanced demo

Configuration Options

Model Configuration

Customize model and training parameters in src/model.py and src/train.py:

# Model Architecture (src/model.py) EMBEDDING_DIM = 256 # Embedding dimension LSTM_UNITS = 512 # LSTM hidden units ATTENTION_UNITS = 256 # Attention mechanism units VOCAB_SIZE = 10000 # Vocabulary size MAX_SEQ_LENGTH = 50 # Maximum sequence length # Training Parameters (src/train.py) BATCH_SIZE = 64 # Training batch size LEARNING_RATE = 0.001 # Learning rate NUM_EPOCHS = 50 # Number of training epochs VALIDATION_SPLIT = 0.2 # Validation split ratio # Chatbot Configuration BEAM_WIDTH = 5 # Beam search width TEMPERATURE = 1.0 # Temperature sampling MAX_HISTORY = 10 # Maximum conversation history length

Advanced Features Usage

Chatbot Usage

Use the chatbot with customizable parameters:

# Basic chatbot from src.chatbot import Chatbot chatbot = Chatbot(model_path='models/lstm_chatbot') response = chatbot.chat("Hello, how are you?") print(response) # Enhanced chatbot with beam search and history from src.chatbot_enhanced import load_enhanced_chatbot chatbot = load_enhanced_chatbot( use_beam_search=True, beam_width=5, use_history=True, max_history=10, temperature=1.0 ) response = chatbot.chat("Hello!") print(response)

Beam Search Decoding

Use beam search for better response quality:

from src.chatbot_enhanced import load_enhanced_chatbot from src.beam_search import generate_with_beam_search # Load chatbot with beam search chatbot = load_enhanced_chatbot( use_beam_search=True, beam_width=5 # Number of candidates to explore ) # Generate response with beam search response = chatbot.chat("Hello, how are you?") # Higher beam width = better quality but slower # Recommended: 3-10 for balance between quality and speed

Model Evaluation

Evaluate model performance with comprehensive metrics:

from src.evaluate_model import evaluate_model from src.evaluation import calculate_bleu_score, calculate_wer # Evaluate model on test dataset results = evaluate_model(model, test_data, processor) # Returns dictionary with: # - bleu_score: BLEU score # - wer: Word Error Rate # - perplexity: Language model perplexity # Calculate individual metrics reference = "hello how are you".split() candidate = "hello how are you doing".split() bleu = calculate_bleu_score(reference, candidate) wer = calculate_wer(reference, candidate) print(f"BLEU Score: {bleu:.4f}") print(f"Word Error Rate: {wer:.4f}")

Data Augmentation

Enhance training data with augmentation techniques:

from src.data_augmentation import ( random_insertion, random_deletion, swap_words, synonym_replacement ) # Augment text data text = "hello how are you" # Random insertion augmented = random_insertion(text, num_insertions=1) # Random deletion augmented = random_deletion(text, deletion_prob=0.1) # Word swapping augmented = swap_words(text, num_swaps=1) # Synonym replacement augmented = synonym_replacement(text, num_replacements=1) # Use augmented data for training to improve model robustness

Temperature Sampling

Control response randomness and creativity with temperature sampling:

from src.chatbot_enhanced import load_enhanced_chatbot # Temperature values: # < 1.0: More deterministic, focused responses # = 1.0: Balanced (default) # > 1.0: More creative, diverse responses # Focused responses chatbot = load_enhanced_chatbot(temperature=0.5) response = chatbot.chat("Hello!") # Balanced responses (default) chatbot = load_enhanced_chatbot(temperature=1.0) response = chatbot.chat("Hello!") # Creative responses chatbot = load_enhanced_chatbot(temperature=1.5) response = chatbot.chat("Hello!")

API Usage Examples

Chat Endpoint (cURL)

Send a chat message and get response with intent and sentiment:

curl -X POST http://localhost:5000/api/chat \ -H "Content-Type: application/json" \ -d '{ "message": "Hello, what is LSTM?", "session_id": "user123" }' # Response: # { # "response": "LSTM is a recurrent neural network...", # "session_id": "user123", # "timestamp": "2025-01-15T10:30:00" # }

Text Generation (cURL)

Generate text from a prompt:

curl -X POST http://localhost:5000/api/generate \ -H "Content-Type: application/json" \ -d '{ "prompt": "Once upon a time", "max_length": 100, "temperature": 0.7 }' # Response: # { # "generated_text": "Once upon a time, in a land far away...", # "length": 100 # }

Batch Generation (cURL)

Generate text from multiple prompts:

curl -X POST http://localhost:5000/api/batch \ -H "Content-Type: application/json" \ -d '{ "prompts": ["Prompt 1", "Prompt 2", "Prompt 3"], "max_length": 100 }' # Response: # { # "results": [ # {"prompt": "Prompt 1", "generated": "..."}, # {"prompt": "Prompt 2", "generated": "..."} # ] # }

Model Evaluation (cURL)

Evaluate model performance:

curl -X POST http://localhost:5000/api/evaluate \ -H "Content-Type: application/json" \ -d '{ "test_file": "data/val.txt", "model": "lstm_chatbot" }' # Response: # { # "perplexity": 25.3, # "avg_generation_time": 0.05, # "tokens_per_second": 20.0 # }

Python Requests Example

Use the API with Python requests library:

import requests # Chat endpoint response = requests.post( 'http://localhost:5000/chat', json={ 'message': 'Hello, how are you?', 'session_id': 'user123' } ) data = response.json() print(f"Bot: {data['response']}") print(f"Intent: {data['intent']}") print(f"Sentiment: {data['sentiment']}") # Get context context = requests.get('http://localhost:5000/context/user123') print(context.json()) # Clear context requests.delete('http://localhost:5000/context/user123')

LSTM Model Variants

Model Parameters Size Use Case Speed
Small LSTM 128 units ~10-20 MB Fast inference, basic tasks Fastest
Medium LSTM 256 units ~30-50 MB Balanced quality/speed Fast
Large LSTM 512 units ~100-200 MB Higher quality generation Moderate
XL LSTM 1024 units ~300-500 MB Best quality, research Slower

Dataset Information

Training Datasets

The project includes multiple domain-specific datasets for fine-tuning:

  • General training data (train.txt, val.txt)
  • Technical domain data
  • Creative writing samples
  • Conversation samples (Q&A pairs)
  • Science & technology topics
  • Business & economics content
  • Health & wellness topics
  • Education & learning content
  • Philosophy & ethics topics
  • History & culture content
  • Sample prompts (text and JSON formats)
  • Advanced training examples

Data Format

Training data is stored in plain text format (one example per line):

# train.txt format (one example per line) Machine learning is a subset of artificial intelligence. LSTM (Long Short-Term Memory) is a recurrent neural network architecture. Natural language processing enables computers to understand text. Deep learning uses neural networks with multiple layers. Text generation creates coherent sequences of words. # For batch generation, JSON format: [ {"prompt": "Once upon a time", "max_length": 100}, {"prompt": "In a galaxy far away", "max_length": 100} ]

Adding Custom Training Data

Add your own text data for fine-tuning:

# Simply append to training file with open('data/train.txt', 'a', encoding='utf-8') as f: f.write("Your custom training text here.\n") f.write("Each line is a separate training example.\n") f.write("The model will learn from these examples.\n") # Or create a new domain-specific file with open('data/domain_custom.txt', 'w', encoding='utf-8') as f: f.write("Domain-specific training data...\n") # Use in training python train.py --train_file data/domain_custom.txt --output_dir models/custom

Troubleshooting & Best Practices

Common Issues

  • CUDA Out of Memory: Reduce batch_size in src/train.py, use smaller LSTM units (128 instead of 512), or use CPU mode
  • Model Not Found: Ensure model is trained first by running src/train.py or loading from models/ directory
  • Slow Generation: Use smaller LSTM units (128 or 256) or reduce beam_width for faster inference
  • API Connection Error: Check if app.py is running on port 5000
  • Import Errors: Verify all dependencies installed: pip install -r requirements.txt
  • Context Too Long: Reduce CONTEXT_LENGTH in config.py or MAX_LENGTH
  • Repetitive Output: Adjust temperature (higher) or repetition_penalty (higher) in config.py

Best Practices

  • Training Data: Use diverse, high-quality text data for better results
  • Context Management: Keep CONTEXT_LENGTH between 3-7 for optimal performance
  • Batch Size: Use smaller batches (4-8) for limited GPU memory, especially with larger models
  • Learning Rate: Start with 5e-5 and adjust based on training loss
  • Temperature: Use 0.7-0.9 for creative text, 0.3-0.5 for more focused output
  • Model Selection: Start with 128-256 LSTM units for speed, use 512 or larger for quality
  • Evaluation: Regularly evaluate perplexity on validation set during training
  • Session Management: Use unique session_ids for different users
  • API Rate Limiting: Implement rate limiting for production deployments
  • Logging: Monitor training logs for debugging and optimization

Performance Optimization

  • GPU Usage: Set CUDA_VISIBLE_DEVICES for multi-GPU systems
  • Model Selection: Use 128-256 LSTM units for fastest inference, larger units for better quality
  • Batch Processing: Use batch_generate.py for processing multiple prompts efficiently
  • Caching: Cache model and tokenizer to avoid reloading
  • Context Pruning: Remove old context beyond CONTEXT_LENGTH
  • Generation Parameters: Adjust temperature, top_p, and top_k for desired output style

Contact Information

Get in Touch

Developer: Molla Samser
Designer & Tester: Rima Khatun

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help@rskworld.in support@rskworld.in
+91 93305 39277

License

This project is for educational purposes only. See LICENSE file for more details.

About RSK World

Founded by Molla Samser, with Designer & Tester Rima Khatun, RSK World is your one-stop destination for free programming resources, source code, and development tools.

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Designer & Tester: Rima Khatun

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