add lazy evalution src/XAD/BinaryExpr.hpp

[rghouzra]

i want to implement lazy evaluation and i want to use atomic for safe thread initialization is it okay?

[auto-differentiation-dev]

Thank you @rghouzra for bringing up the idea of implementing lazy evaluation and using atomic for thread-safe initialisation – it's great to see contributors like you thinking about new ways to enhance XAD! 🚀

We're excited to explore this further with you, but we'd love some clarification on your ideas to ensure we fully understand your approach. A couple of thoughts from our side:

• Lazy evaluation: If you’re referring to binary or general expressions, these are already lazily evaluated through expression templates, which is a core feature of XAD. However, you might have something more specific in mind – could you elaborate on your goals and use case?

• Thread-safe initialisation: For tape recording, thread safety isn't typically necessary since XAD recommends using thread-local tapes (one tape per thread) to handle concurrent environments. Could you share more details on the context where you envision thread-safe initialisation would be needed?

We're eager to hear your thoughts and dive deeper into how this could fit into the library. Those kind of ideas are invaluable to shaping XAD's future, and we're here to collaborate and support you in bringing them to life.

Looking forward to your insights!