1)install
conda init
vi ./condarc
channels:
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/pytorch/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/menpo/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/bioconda/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/msys2/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/
  
conda config --add channels diffpy
conda create --name=py27 python=2.7
conda activate py27
conda install diffpy.pdffit2
conda install diffpy.pdfgui



2)uninstall
conda install anaconda-clean
anaconda-clean --yes


vi libpdffit2/parser.cc
stack
to
::stack

brew install gsl

pip install -U wxPython