principal_axes_from_inertia_tensors

halotools.mock_observables.principal_axes_from_inertia_tensors(inertia_tensors)[source] [edit on github]

Calculate the principal eigenvector of each of the input inertia tensors.

Parameters:

inertia_tensors : ndarray

Numpy array of shape (npts, 3, 3) storing a collection of 3x3 symmetric positive-definite matrices

Returns:

principal_axes : ndarray

Numpy array of shape (npts, 3) storing a collection of 3d principal eigenvectors

eigenvalues : ndarray

Numpy array of shape (npts, ) storing the eigenvalue of each principal eigenvector

Notes

The function inertia_tensor_per_object calculates the inertia tensors \(\mathcal{I}_{\rm i}\) for a collection of points inside a 3d mass distribution.