import tensorflow.contrib.slim as slim

        with tf.Graph().as_default() as graph, tf.device('/cpu:0'):

            num_gpu = len(cfgs.GPU_GROUP.strip().split(','))
            global_step = slim.get_or_create_global_step()
            lr = self.warmup_lr(cfgs.LR, global_step, cfgs.WARM_SETP, num_gpu)
            tf.summary.scalar('lr', lr)
