大佬，请问如何指定gpu训练

[ccijunk]

例如，我在一张8卡节点上训练，想用其中4张训练 如果我用0，1，2，3是可以训练的 但是如果我用 其他任意组合的gpuid就不可以

我参考了这个把每个进程的gpuid 改了 https://github.com/PyTorchLightning/pytorch-lightning/issues/2407

会提示 RuntimeError: cuda runtime error (10) : invalid device ordinal at /pytorch/torch/csrc/cuda/Module.cpp:59

我的代码

import torch
import torch.nn as nn
import torch.distributed as dist
import torch.utils.data.distributed
import torch.multiprocessing as mp
import argparse
import os



parser = argparse.ArgumentParser(description = 'multi process')

parser.add_argument('--gpu-id',type =str,default='0,1,2,4')
parser.add_argument('--world-size', default=1, type=int,
                    help='number of nodes for distributed training')
parser.add_argument('--rank', default=0, type=int,
                    help='node rank for distributed training')
parser.add_argument('--dist-url', default='tcp://localhost:23456', type=str,
                    help='url used to set up distributed training')
parser.add_argument('--dist-backend', default='nccl', type=str,
                    help='distributed backend')
args = parser.parse_args()






def  main():
    global args


    os.environ['CUDA_VISIBLE_DEVICES'] = args.gpu_id
    # args.gpu = list(map(int,args.gpu_id.split(',')))

    # state = {k: v for k, v in args._get_kwargs()}

    # ngpus_per_node = torch.cuda.device_count() #len(args.gpu)

    ngpus_per_node = args.gpu_id.split(',').__len__()
    # print(os.environ['CUDA_VISIBLE_DEVICES'])
    # print('能看到的gpu',ngpus_per_node)
    args.nprocs = ngpus_per_node
    args.world_size = ngpus_per_node * args.world_size
    mp.spawn(main_worker, nprocs=ngpus_per_node, args=(ngpus_per_node, args))


# Random seed

# best_acc = 0  # best test accuracy

def main_worker(local_rank,ngpus_per_node,args):
    # global best_acc
 # start from epoch 0 or last checkpoint epoch

    # if not os.path.isdir(args.checkpoint):
    #     mkdir_p(args.checkpoint)
    # # import pdb
    # pdb.set_trace()
    gpus = os.environ['CUDA_VISIBLE_DEVICES'].split(',')
    gpu = int(gpus[local_rank])

    args.gpu = gpu
    best_acc = 0
    # print(best_acc)
    args.rank = args.rank * ngpus_per_node + local_rank#args.gpu[gpu]
    print('rank: {} / {}'.format(args.rank, args.world_size))

    dist.init_process_group(backend=args.dist_backend,
                            init_method=args.dist_url,
                            world_size=args.world_size,
                            rank=args.rank)



    torch.cuda.set_device(gpu)


if __name__ == '__main__':
    main()`