Explain the mechanics of the Ring-AllReduce algorithm and how it scales as you increase the number of GPU nodes for distributed training on AMD Instinct.
Implement ring_all_reduce(tensors) to simulate reduce-scatter followed by all-gather for equal-length GPU tensors. Return the element-wise sum replicated on every node, along with the number of communication rounds and point-to-point messages.
def ring_all_reduce(tensors):