Appendix

A Algorithm Procedure A full workflow of channel number search with the proposed transitionary APS is shown in Algorithm 1. The overall procedure consists of two stages. In the first stage, we fix the controller () and initialize of affine parameter sharing with maximal value, so that meta weights W can be efficiently optimized. During this stage architectures are uniformly sampled from the search space C and are thus equally updated. We alternatively update meta weights W and controller parameter based on architectures sampled from the controller.