  One-Shot Neural Architecture Search (NAS) is a promising method to
significantly reduce search time without any separate training. It can be
treated as a Network Compression problem on the architecture parameters from an
over-parameterized network. However, there are two issues associated with most
one-shot NAS methods. First, dependencies between a node and its predecessors
and successors are often disregarded which result in improper treatment over
zero operations. Second, architecture parameters pruning based on their
magnitude is questionable. In this paper, we employ the classic Bayesian
learning approach to alleviate these two issues by modeling architecture
parameters using hierarchical automatic relevance determination (HARD) priors.
Unlike other NAS methods, we train the over-parameterized network for only one
epoch then update the architecture. Impressively, this enabled us to find the
architecture on CIFAR-10 within only 0.2 GPU days using a single GPU.
Competitive performance can be also achieved by transferring to ImageNet. As a
byproduct, our approach can be applied directly to compress convolutional
neural networks by enforcing structural sparsity which achieves extremely
sparse networks without accuracy deterioration.
