where Z= PK k e

A.1 Mixedoperation For spiking neurons, we can either mix the operation at the spike activation or at the input of the membranepotential. For mixed operation at the input of membrane potential, as Eq. 4 shows, the gradient ofαk applies a unified SGfunctiong(u)fordifferent candidate operations which limits theexploration ofdiverse SGfunctions. However,sinceIk directly depends ontheweight, whenappliedforDGSmethod it strictly reflects different changes oftheoriginal weight, thus giving more accurate learning signals forαk. Meanwhile it's also a spike emitter to transmit floating numbers to spikes. Then we employ cell structure as our basic unit to construct our whole searching structure.