# angles_between_list_of_vectors¶

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

Calculate the angle between a collection of n-dimensional vectors

Parameters:
v0ndarray

Numpy array of shape (npts, ndim) storing a collection of ndim-D vectors Note that the normalization of `v0` will be ignored.

v1ndarray

Numpy array of shape (npts, ndim) storing a collection of ndim-D vectors Note that the normalization of `v1` will be ignored.

tolfloat, 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.

n1ndarray

normal vector

Returns:
anglesndarray

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)
```