> For the complete documentation index, see [llms.txt](https://lichangbin.gitbook.io/paper_notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lichangbin.gitbook.io/paper_notes/oct/continuous-meta-learning-without-tasks.md).

# Continuous Meta Learning without tasks

## Motivation

Meta-learning is a promising strategy for learning to efficiently learn within new tasks, using data gathered from a distribution of tasks.&#x20;

However, the meta-learning literature thus far has focused on the task segmented setting, where at train-time, offline data is assumed to be split according to the underlying task, and at test-time, the algorithms are optimized to learn in a single task.&#x20;

In this work, we enable the application of generic meta-learning algorithms to settings where this task segmentation is unavailable, such as continual online learning with a time-varying task.&#x20;

We present meta-learning via online changepoint analysis (MOCA), an approach which augments a meta-learning algorithm with a differentiable Bayesian changepoint detection scheme.

## Problem Statement

![](/files/-MKYFKLGCyyV9hzWKX7M)

We assume that we have access to a representative time series generated in the same manner from the same distribution of tasks, and use this time series to optimize in an offline, meta-training phase.&#x20;

Critically, however, in stark contrast to standard meta-learning approaches, we do not assume access to task segmentation.&#x20;

Moreover, we highlight that we consider the case of individual data points provided sequentially, in contrast to the common “k-shot, n-way” problem setting prevalent in few-shot learning (especially classification).

## Bayesian Online Changepoint Detection (BOCPD)

We build on Bayesian online changepoint detection (Adams & MacKay, 2007), an approach for detecting changepoints (i.e. task switches) originally presented in a streaming unconditional density estimation context.

BOCPD operates by maintaining a belief distribution over run lengths, i.e. how many of the past data points $$y\_t$$ correspond to the current task.

In this work, we extend this approach of Adams & MacKay (2007) beyond Bayesian unconditional density estimation to apply to general meta-learning models operating in the conditional density estimation setting.

Details could be found from: [http://gregorygundersen.com/blog/2019/08/13/bocd/&#x20; <br>](<http://gregorygundersen.com/blog/2019/08/13/bocd/ &#xD;&#xA;>)

![](/files/-MKYFsP7hTXOc4AItLYJ)

## Overview of MOCA

![](/files/-MKYG-zr6B6Xc8oy3IVz)

## Meta-Learning via Online Changepoint Analysis

![](/files/-MKYG5vRsiAKqHcDqfyN)

![](/files/-MKYG9yx-C_ux41zo8J3)

#### NOTE: Adding more about Connection with meta-learning, online learning, and continual learning

## Reference

* <https://arxiv.org/pdf/1912.08866.pdf> (latest version)
