PyTorch出现：RuntimeError: An attempt has been made to start a new process...报错 PyTorch出现：RuntimeError: An attempt has been made to start a new process...报错

1.查看显卡：

第一步：同时按下键盘的win+r键，输入cmd

第二步：随后输入

nvidia-smi

2.查看下载安装的包：

conda list

conda list

3.问题报错

PyTorch出现：RuntimeError: An attempt has been made to start a new process...报错

RuntimeError: 
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.
 
        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:
 
            if __name__ == '__main__':
                freeze_support()
                ...
 
        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.

出错原因：网上查找结果，原因是多进程的原因

解决方法：

1. 代码在运行 epoch 之前，加上    if __name__=='__main__'

2， 不使用多线程，即去掉 num_workers 参数，或设置 num_workers=0。

dataset = torch.utils.data.DataLoader(trainset, batch_size=opt.batch_size,
                                        shuffle=True, num_workers=0, drop_last=True)