zernikeGradEval

lsst.ts.wep.utils.zernikeGradEval(u, v, uOrder, vOrder, zkCoeff, jmin=4, obscuration=0.612)

Evaluate the gradient of the Zernike series.

This function is evaluated at the provided u and v coordinates, where these coordinates are normalized pupil coordinates. Normalized pupil coordinates are defined such that u^2 + v^2 = 1 is the edge of the pupil, and u^2 + v^2 = obscuration^2 is the edge of the central obscuration.

Parameters:

• u (np.ndarray) – The x normalized pupil coordinate(s).

• v (np.ndarray) – The y normalized pupil coordinate(s). Must be same shape as u.

• uOrder (int) – The number of u derivatives to apply.

• vOrder (int) – The number of v derivatives to apply.

• zkCoeff (np.ndarray) – Zernike coefficients in any units.

• jmin (int, optional) – The minimum Noll index, inclusive. Must be >= 0. (the default is 4)

• obscuration (float, optional) – The fractional obscuration. (the default is 0.612, corresponding to the Simonyi Survey Telescope.)

Returns:

Values of the Zernike series at the given points. Has the same shape as u and v, and the same units as zkCoeff.

Return type:

np.ndarray

Raises:

ValueError – If jmin is negative