Improving Federated Learning Personalization via MAML Paper Notes (Incomplete)
Improving Federated Learning Personalization via MAML Abstract FL algorithms share many similarities with MAML and can be interpreted through meta-learning algorithms Fine-tuning gives the global model stronger accuracy while making personalization easier Models trained on standard centralized datasets are harder to personalize than those trained with FedAvg Introduction Points out the connection between FL and MAML, and interprets the FL algorithm via MAML Improves FedAvg with a two-stage approach of training and fine-tuning Finds that FedAvg is essentially a meta-learning algorithm that optimizes personalization performance rather than the global model. Interpreting FedAvg as a Meta Learning Algorithm The figure below shows MAML applied in the FL setting (left), the Reptile algorithm (middle), and FedAvg, the training algorithm of FL (right). Let L be the loss function. In each round of iteration, MAML trains by randomly sampling a batch of tasks T. For each task T there is an inner loop, and the outer loop aggregates the gradient updates obtained from each task. The FL algorithm randomly samples several clients T. For each T and its weight, several rounds of local optimization are performed, and the updated gradients are aggregated into a new global model. If we simplify the setting and assume all clients have the same amount of data, all weights become equal, and Reptile and FedAvg are then effectively the same algorithm. ...