# angles_between_list_of_vectors¶

halotools.utils.angles_between_list_of_vectors(v0, v1, tol=0.001, vn=None)[source] [edit on github]

Calculate the angle between a collection of n-dimensional vectors

Parameters: v0 : ndarray Numpy array of shape (npts, ndim) storing a collection of ndim-D vectors Note that the normalization of v0 will be ignored. v1 : ndarray Numpy array of shape (npts, ndim) storing a collection of ndim-D vectors Note that the normalization of v1 will be ignored. tol : float, optional Acceptable numerical error for errors in angle. This variable is only used to round off numerical noise that otherwise causes exceptions to be raised by the inverse cosine function. Default is 0.001. n1 : ndarray normal vector angles : ndarray Numpy array of shape (npts, ) storing the angles between each pair of corresponding points in v0 and v1. Returned values are in units of radians spanning [0, pi].

Examples

Let’s create two sets of semi-random 3D unit vectors.

>>> npts = int(1e4)
>>> ndim = 3
>>> v1 = np.random.random((npts, ndim))
>>> v2 = np.random.random((npts, ndim))


We then can find the angle between each pair of vectors in v1 and v2.

>>> angles = angles_between_list_of_vectors(v1, v2)