How to Train Your Metamorphic Deep Neural Network
Thomas Sommariva, Simone Calderara, Angelo Porrello
TL;DR
This work expands Neural Metamorphosis (NeuMeta) from metamorphosing only the final blocks to full-network metamorphosis by introducing a block-wise, incremental training strategy that leverages Implicit Neural Representations (INRs) to model a continuous weight manifold. Key innovations include INR pre-initialization, learnable residual scaling to replace Batch Normalization, gradient accumulation over multiple configurations, and disentangled INRs for weights and biases, enabling stable training across varying compression ratios denoted by the factor $\\gamma$. Empirical results on ResNet-56 with CIFAR-100 show substantial accuracy gains over NeuMeta and pruning baselines, with near-baseline performance under aggressive compression and clear evidence of improved scalability with network width. The approach demonstrates the feasibility of deploying dynamically adaptable metamorphic networks, potentially enabling efficient, on-device inference across heterogeneous environments. The work also discusses generalization and trade-offs between in-distribution performance and flexibility to unseen configurations, outlining future work to extend metamorphism to other architectures like QRNNs and ViT.
Abstract
Neural Metamorphosis (NeuMeta) is a recent paradigm for generating neural networks of varying width and depth. Based on Implicit Neural Representation (INR), NeuMeta learns a continuous weight manifold, enabling the direct generation of compressed models, including those with configurations not seen during training. While promising, the original formulation of NeuMeta proves effective only for the final layers of the undelying model, limiting its broader applicability. In this work, we propose a training algorithm that extends the capabilities of NeuMeta to enable full-network metamorphosis with minimal accuracy degradation. Our approach follows a structured recipe comprising block-wise incremental training, INR initialization, and strategies for replacing batch normalization. The resulting metamorphic networks maintain competitive accuracy across a wide range of compression ratios, offering a scalable solution for adaptable and efficient deployment of deep models. The code is available at: https://github.com/TSommariva/HTTY_NeuMeta.
