FischGPT-SFT

Model Description

FischGPT-SFT is a supervised fine-tuned GPT-2 style transformer model built completely from scratch using PyTorch. This implementation demonstrates deep understanding of transformer architecture and industry-standard training practices.

Key Features

• From-scratch implementation: Every component built without using pre-existing transformer libraries
• Flash Attention: Implements efficient attention using F.scaled_dot_product_attention
• Professional Architecture: Clean separation of attention, MLP, and transformer blocks
• Industry Training: Follows OpenAI's GPT-2 training methodology
• Production Ready: Includes proper weight initialization and distributed training support

Model Architecture

Parameter	Value
Model Type	GPT-2 Style Decoder
Layers	12
Hidden Size	768
Attention Heads	12
Context Length	1024
Vocabulary Size	50,304
Parameters	~124M

Training Details

• Model Type: Supervised Fine-Tuned
• Training Data: OpenAssistant/oasst1
• Training Steps: 19,999 steps
• Final Validation Loss: 1.725750207901001
• Tokenizer: GPT-2 BPE (tiktoken)
• Framework: PyTorch with mixed precision (bfloat16)

Training Infrastructure

• Distributed Training: Multi-GPU support with DistributedDataParallel
• Optimization: AdamW with cosine learning rate schedule
• Regularization: Weight decay, dropout, gradient clipping
• Monitoring: Comprehensive logging and checkpoint management

Usage

from transformers import GPT2LMHeadModel, GPT2Tokenizer

# Load model and tokenizer
model = GPT2LMHeadModel.from_pretrained('fischgpt-sft')
tokenizer = GPT2Tokenizer.from_pretrained('fischgpt-sft')

# Generate text
input_text = "The future of artificial intelligence"
inputs = tokenizer.encode(input_text, return_tensors='pt')

with torch.no_grad():
    outputs = model.generate(
        inputs,
        max_length=100,
        num_return_sequences=1,
        temperature=0.8,
        do_sample=True,
        pad_token_id=tokenizer.eos_token_id
    )

generated_text = tokenizer.decode(outputs[0], skip_special_tokens=True)
print(generated_text)

Chat Format (for SFT models)

def chat_format(user_message):
    return f"<|user|>{user_message}<|assistant|>"

prompt = chat_format("Explain quantum computing in simple terms")
# ... generate as above

Implementation Highlights

Custom Components

• CasualSelfAttention: Implements multi-head self-attention with causal masking
• MLP: Feed-forward network with GELU activation and custom initialization
• Block: Transformer block with pre-layer normalization
• GPT: Complete model with tied embeddings and generation capabilities

Advanced Features

# Flash Attention Implementation
y = F.scaled_dot_product_attention(q, k, v, is_causal=True)

# Custom Weight Initialization
if hasattr(module, "FISCHGPT_SCALE_INIT"):
    std *= (2 * self.config.n_layer) ** -.5

Performance & Benchmarks

Metric	Value
Training Speed	~1200000 tokens/sec
Memory Efficiency	Mixed precision (bfloat16)
Context Length	1024 tokens
Generation Speed	Fast inference with optimized attention

Technical Specifications

• Attention Pattern: Causal (autoregressive)
• Activation Function: GELU (approximate='tanh')
• Normalization: Layer Normalization
• Position Encoding: Learned positional embeddings
• Weight Tying: Shared input/output embeddings

Use Cases

• Conversational AI, Instruction Following
• Code completion and programming assistance
• Creative writing and storytelling
• Educational content generation
• Research and experimentation

Limitations

• Context length limited to 1024 tokens
• English-focused training data
• Requires careful prompt engineering for best results
• May generate inconsistent or incorrect information

Ethics and Safety

This model was trained on publicly available datasets and may reflect biases present in the training data. Users should:

• Validate generated content for accuracy
• Be aware of potential biases in outputs
• Use appropriate content filtering for production applications
• Follow responsible AI practices

Citation

@misc{fischgpt2024,
  title={FischGPT: A From-Scratch GPT-2 Implementation},
  author={[Your Name]},
  year={2024},
  howpublished={\url{https://github.com/yourusername/FischGPT}}
}

License

MIT License - See LICENSE file for details.

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Built with industry best practices and attention to detail. This implementation showcases deep understanding of transformer architecture and modern NLP engineering.