OpenAI Baselines adds ACKTR and A2C implementations for RL experiments

AI Impact Summary

OpenAI Baselines now includes ACKTR and A2C implementations, expanding the RL toolkit. A2C provides a synchronous, deterministic variant of A3C with similar performance, while ACKTR delivers higher sample efficiency than TRPO and A2C at a slightly higher per-update compute cost. This gives teams options to accelerate experimentation and potentially reduce data requirements, but they should validate compute budgets and ensure compatibility with existing training pipelines before replacing current baselines.