Timezone: »

How to distribute data across tasks for meta-learning?
Alexandru Cioba · Michael Bromberg · Qian Wang · RITWIK NIYOGI · Georgios Batzolis · Jezabel Garcia · Da-shan Shiu · Alberto Bernacchia
Event URL: https://openreview.net/forum?id=o1plirEdhtZ »

Meta-learning models transfer the knowledge acquired from previous tasks to quickly learn new ones. They are trained on benchmarks with a fixed number of data points per task. This number is usually arbitrary and it is unknown how it affects performance at testing. Since labelling of data is expensive, finding the optimal allocation of labels across training tasks may reduce costs. Given a fixed budget of labels, should we use a small number of highly labelled tasks, or many tasks with few labels each? Should we allocate more labels to some tasks and less to others?We show that: 1) If tasks are homogeneous, there is a uniform optimal allocation, whereby all tasks get the same amount of data; 2) At fixed budget, there is a trade-off between number of tasks and number of data points per task, with a unique and constant optimum; 3) When trained separately, harder task should get more data, at the cost of a smaller number of tasks; 4) When training on a mixture of easy and hard tasks, more data should be allocated to easy tasks. Interestingly, Neuroscience experiments have shown that human visual skills also transfer better from easy tasks. We prove these results mathematically on mixed linear regression, and we show empirically that the same results hold for few-shot image classification on CIFAR-FS and mini-ImageNet. Our results provide guidance for allocating labels across tasks when collecting data for meta-learning.

Author Information

Alexandru Cioba (Mediatek Research)
Michael Bromberg (Mediatek Research)
Qian Wang (mediatek research)
RITWIK NIYOGI (University College London)
Georgios Batzolis (University of Cambridge)
Jezabel Garcia (MediaTek Research)
Da-shan Shiu (University of California Berkeley)
Alberto Bernacchia (MediaTek Research)

More from the Same Authors