export CUDA_VISIBLE_DEVICES="0,1,2,3" ./zipformer/train.py \ --world-size 4 \ --num-epochs 30 \ --start-epoch 1 \ --use-fp16 1 \ --exp-dir zipformer/exp-causal \ --causal 1 \ --full-libri 1 \ --max-duration 1000 \ --master-port 12345