Learngene: Inheriting Condensed Knowledge from the Ancestry Model to Descendant Models

TL;DR

Learngene is a novel machine learning paradigm inspired by biological genes, focusing on condensing accumulated knowledge from an ancestor model into a compact form that can be inherited by descendant models to improve learning efficiency and performance.

Contribution

The paper introduces the concept of Learngene, a method for condensing and inheriting knowledge from an ancestor model to enhance descendant models' adaptation and learning speed.

Findings

Descendant models converge faster with Learngene.

Learngene reduces sensitivity to hyperparameters.

Models with Learngene perform better and need fewer training samples.

Abstract

During the continuous evolution of one organism's ancestry, its genes accumulate extensive experiences and knowledge, enabling newborn descendants to rapidly adapt to their specific environments. Motivated by this observation, we propose a novel machine learning paradigm Learngene to enable learning models to incorporate three key characteristics of genes. (i) Accumulating: the knowledge is accumulated during the continuous learning of an ancestry model. (ii) Condensing: the extensive accumulated knowledge is condensed into a much more compact information piece, i.e., learngene. (iii) Inheriting: the condensed learngene is inherited to make it easier for descendant models to adapt to new environments. Since accumulating has been studied in well-established paradigms like large-scale pre-training and lifelong learning, we focus on condensing and inheriting, which induces three key issues and we provide the preliminary solutions to these issues in this paper: (i) Learngene Form: the learngene is set to a few integral layers that can preserve significance. (ii) Learngene Condensing: we identify which layers among the ancestry model have the most similarity as one pseudo descendant model. (iii) Learngene Inheriting: to construct distinct descendant models for the specific downstream tasks, we stack some randomly initialized layers to the learngene layers. Extensive experiments across various settings, including using different network architectures like Vision Transformer (ViT) and Convolutional Neural Networks (CNNs) on different datasets, are carried out to confirm four advantages of Learngene: it makes the descendant models 1) converge more quickly, 2) exhibit less sensitivity to hyperparameters, 3) perform better, and 4) require fewer training samples to converge.