poliastro.core.util

Module Contents

Functions

eccentricity_vector(k, r, v)
circular_velocity(k, a)	Compute circular velocity for a given body given thegravitational parameter and the semimajor axis.
rotation_matrix(angle, axis)
alinspace(start, stop=None, num=50, endpoint=True)	Return increasing, evenly spaced angular values over a specified interval.
spherical_to_cartesian(v)	Compute cartesian coordinates from spherical coordinates (norm, colat, long). This function is vectorized.

poliastro.core.util.eccentricity_vector(k, r, v)

poliastro.core.util.circular_velocity(k, a)

Compute circular velocity for a given body given thegravitational parameter and the semimajor axis.

\[v = \sqrt{\frac{\mu}{a}}\]

Parameters

• k (float) – Gravitational Parameter

• a (float) – Semimajor Axis

poliastro.core.util.rotation_matrix(angle, axis)

poliastro.core.util.alinspace(start, stop=None, num=50, endpoint=True)

Return increasing, evenly spaced angular values over a specified interval.

poliastro.core.util.spherical_to_cartesian(v)

Compute cartesian coordinates from spherical coordinates (norm, colat, long). This function is vectorized.

\[\begin{split}v = norm \cdot \begin{bmatrix} \sin(colat)\cos(long)\\ \sin(colat)\sin(long)\\ \cos(colat)\\ \end{bmatrix}\end{split}\]

Parameters

v (np.array) – Spherical coordinates in 3D (norm, colat, long). Angles must be in radians.

Returns

v – Cartesian coordinates (x,y,z)

Return type

np.array