conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge 
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/msys2
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/pytorch/
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/r
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main
conda config --set show_channel_urls yes

show_channel_urls: true
channel_alias: https://mirrors.tuna.tsinghua.edu.cn/anaconda
default_channels:
 - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main
 - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
 - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/r
 - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/pro
 - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/msys2
 - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/pytorch/
custom_channels:
 conda-forge: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
 msys2: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
 bioconda: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
 menpo: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
 pytorch: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
 simpleitk: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud

创建：
conda create -n 环境名 python=X.X
开启：
activate 环境名
关闭：
conda deactivate
删除：
conda remove -n 环境名 --all
添加包：
conda install -n 环境名 包名
移除包：
conda remove -n 环境名 包名

conda install pytorch torchvision cudatoolkit=10.1 -c pytorch (要去掉-c pytorch 不然还是默认源)
最终输入命令:
conda install pytorch torchvision cudatoolkit=10.1

import torch
flag = torch.cuda.is_available()
print(flag)
 
ngpu= 1
# Decide which device we want to run on
device = torch.device("cuda:0" if (torch.cuda.is_available() and ngpu > 0) else "cpu")
print(device)
print(torch.cuda.get_device_name(0))
print(torch.rand(3,3).cuda())