Created by: wanghaoshuang

Please register SGD in this script: https://github.com/PaddlePaddle/PaddleSlim/blob/release/1.0.1/paddleslim/prune/prune_walker.py#L526

Add lines as below:

@PRUNE_WORKER.register
class sgd(PruneWorker):
    def __init__(self, op, pruned_params, visited={}):
        super(sgd, self).__init__(op, pruned_params, visited)

    def _prune(self, var, pruned_axis, pruned_idx):
        pass

We will fix this issue by skipping default operators in the next version.