text: import numpy as np
  import torch
  
  NCa_bond = torch.tensor(1.453).float()
  CaC_bond = torch.tensor(1.526).float()
  NCaC_angle = np.deg2rad(109.5)
  cos_NCaC = np.cos(NCaC_angle)
  sin_NCaC = np.sin(NCaC_angle)
  #
  init_N = torch.tensor([-NCa_bond.item(), 0.0, 0.0]).float()
  init_C = torch.tensor([-CaC_bond.item()*cos_NCaC, CaC_bond.item()*sin_NCaC, 0.0]).float()
  init_CA = torch.zeros_like(init_N)
  INIT_CRDS = torch.stack((init_N, init_CA, init_C), dim=0) # (3,3) 
  
  #INIT_CRDS = torch.tensor([
  #    [ # ala
  #        [-0.525, 1.363, 0.000], # N
  #        [0.000, 0.000, 0.000], # CA
  #        [1.526, -0.000, -0.000], # C
  #    ],
  #    [ # arg
  #        [-0.524, 1.362, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.525, -0.000, -0.000],
  #    ],
  #    [ # asn
  #        [-0.536, 1.357, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.526, -0.000, -0.000],
  #    ],
  #    [ # asp
  #        [-0.525, 1.362, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.527, 0.000, -0.000],
  #    ],
  #    [ # cys
  #        [-0.522, 1.362, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.524, 0.000, 0.000],
  #    ],
  #    [ # gln
  #        [-0.526, 1.361, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.526, 0.000, 0.000],
  #    ],
  #    [ # glu
  #        [-0.528, 1.361, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.526, -0.000, -0.000],
  #    ],
  #    [ # gly
  #        [-0.572, 1.337, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.517, -0.000, -0.000],
  #    ],
  #    [ # his
  #        [-0.527, 1.360, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.525, 0.000, 0.000],
  #    ],
  #    [ # ile
  #        [-0.493, 1.373, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.527, -0.000, -0.000],
  #    ],
  #    [ # leu
  #        [-0.520, 1.363, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.525, -0.000, -0.000],
  #    ],
  #    [ # lys
  #        [-0.526, 1.362, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.526, 0.000, 0.000],
  #    ],
  #    [ # met
  #        [-0.521, 1.364, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.525, 0.000, 0.000],
  #    ],
  #    [ # phe
  #        [-0.518, 1.363, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.524, 0.000, -0.000],
  #    ],
  #    [ # pro
  #        [-0.566, 1.351, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.527, -0.000, 0.000],
  #    ],
  #    [ # ser
  #        [-0.529, 1.360, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.525, -0.000, -0.000],
  #    ],
  #    [ # thr
  #        [-0.517, 1.364, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.526, 0.000, -0.000],
  #    ],
  #    [ # trp
  #        [-0.521, 1.363, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.525, -0.000, 0.000],
  #    ],
  #    [ # tyr
  #        [-0.522, 1.362, 0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.524, -0.000, -0.000],
  #    ],
  #    [ # val
  #        [-0.494, 1.373, -0.000],
  #        [0.000, 0.000, 0.000],
  #        [1.527, -0.000, -0.000],
  #    ],
  #])
  