yt.utilities.math_utils.
compute_rotational_velocity
(CoM, L, P, V)[source]¶Computes the rotational velocity for some data around an axis.
This is primarily for halo computations. Given some data, this computes the circular rotational velocity of each point (particle) in reference to the axis defined by the angular momentum vector. This is accomplished by converting the reference frame of the center of mass of the halo.
Parameters: | CoM : array
L : array
P : array
V : array
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Returns: | v : array
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Examples
>>> CoM = np.array([0, 0, 0])
>>> L = np.array([0, 0, 1])
>>> P = np.array([[1, 0, 0], [1, 1, 1], [0, 0, 1], [1, 1, 0]])
>>> V = np.array([[0, 1, 10], [-1, -1, -1], [1, 1, 1], [1, -1, -1]])
>>> circV = compute_rotational_velocity(CoM, L, P, V)
>>> circV
array([ 1. , 0. , 0. , 1.41421356])