angle_deriv

angle_deriv(coords, i, j, k): 

Gives the derivative of the angle between i, j, and k with respect to the Cartesians

coords: np.ndarray

No description…
i: int | Iterable[int]

index of the central atom
j: int | Iterable[int]

index of one of the outside atoms
k: int | Iterable[int]

index of the other outside atom
:returns: np.ndarray

derivatives of the angle with respect to atoms i, j, and k