DIFFNAS found the optimal CIFAR-10 architecture without a performance predictor and cut search cost 17.5 times
AspireAI community · arXiv
Neural architecture search stays expensive because most methods either train candidate networks or learn a predictor to estimate their performance. DIFFNAS drops the predictor: it uses a discrete graph diffusion model guided by training-free proxies such as MeCo and SWAP, so the generative search is conditioned on metrics that need no training run. On NAS-Bench-201, DIFFNAS found the optimal architectures for CIFAR-10 and CIFAR-100, at 94.37 percent and 73.51 percent, while reducing search cost by up to 17.5 times compared to DiffusionNAG. The paper is straightforward about where it loses: on the MobileNetV3 search space its accuracy is lower than DiffusionNAG's. So the gain is real on the small proxy benchmarks NAS work is usually evaluated on, and unproven on the constrained architectures that matter most in practice.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.