deepseek-ai/deepseek-math — reverse-engineered prompt

Build me a simple Python project that lets me run DeepSeekMath 7B for math problem solving. It should download one of the public checkpoints from Hugging Face, preferably the instruct model by default, and let me type a problem and get a clear worked solution.

Please include a text completion example too, since the base model supports that. Make it easy to switch between the base, instruct, and RL model names, use GPU automatically if available, and show a friendly message if the machine cannot handle the model.

Add a small command line chat and a minimal web demo if that is reasonable. Include setup instructions, license notes pointing to the model agreement, and a few sample prompts like integrals and competition math. Keep the code clean and runnable, and look up current Hugging Face docs online if needed.