Here, ϕ m i represents the mth torsion within ith geometry, the parameter k n,m i and ϕ eq m i represent the corresponding force constants and equilibrium dihedral angle values. The parameter k n,m i is randomly initialized. If the value of k n,m i is positive, the parameter ϕ eq m i is set as 0; otherwise, it is set as π. Then, k n,m i is updated to minimize the loss defined in eq (5).