def test_d_x_diffr_dx(self):
x = 1
y = 0
out = calc_util.d_x_diffr_dx(x, y)
assert out == 0
x = 0
y = 1
out = calc_util.d_x_diffr_dx(x, y)
assert out == 1
def hessian(self, x, y, sigma0, r_core, center_x=0, center_y=0):
"""
:param x: x-coordinate in angular units
:param y: y-coordinate in angular units
:param sigma0: convergence in the core
:param r_core: core radius
:param center_x: center of the profile
:param center_y: center of the profile
:return: Hessian df/dxdx, df/dxdy, df/dydx, df/dydy at position (x, y)
"""
x_ = x - center_x
y_ = y - center_y
r = np.sqrt(x_**2 + y_**2)
r = np.maximum(r, self._s)
d_alpha_dr = self.d_alpha_dr(r, sigma0, r_core)
alpha = self.alpha_r(r, sigma0, r_core)
dr_dx = calc_util.d_r_dx(x_, y_)
dr_dy = calc_util.d_r_dy(x_, y_)
f_xx = d_alpha_dr * dr_dx * x_ / r + alpha * calc_util.d_x_diffr_dx(
x_, y_)
f_yy = d_alpha_dr * dr_dy * y_ / r + alpha * calc_util.d_y_diffr_dy(
x_, y_)
f_xy = d_alpha_dr * dr_dy * x_ / r + alpha * calc_util.d_x_diffr_dy(
x_, y_)
return f_xx, f_xy, f_xy, f_yy
def hessian(self, x, y, coeff, d_r, d_phi, center_x, center_y):
"""
:param x: x-coordinate
:param y: y-coordinate
:param coeff: float, amplitude of basis
:param d_r: period of radial sinusoidal in units of angle
:param d_phi: period of tangential sinusoidal in radian
:param center_x: center of rotation for tangential basis
:param center_y: center of rotation for tangential basis
:return: f_xx, f_yy, f_xy
"""
r, theta = param_util.cart2polar(x,
y,
center_x=center_x,
center_y=center_y)
dphi_ = d_phi / self._2_pi
d_phi_dr = self._d_phi_r(r, d_r) * self._phi_theta(theta, dphi_)
d_phi_dr2 = self._d_phi_r2(r, d_r) * self._phi_theta(theta, dphi_)
d_phi_d_theta = self._d_phi_theta(theta, dphi_) * self._phi_r(r, d_r)
d_phi_d_theta2 = self._d_phi_theta2(theta, dphi_) * self._phi_r(r, d_r)
d_phi_dr_dtheta = self._d_phi_r(r, d_r) * self._d_phi_theta(
theta, dphi_)
x_ = x - center_x
y_ = y - center_y
dr_dx = derivative_util.d_r_dx(x_, y_)
dr_dy = derivative_util.d_r_dy(x_, y_)
d_theta_dx = derivative_util.d_phi_dx(x_, y_)
d_theta_dy = derivative_util.d_phi_dy(x_, y_)
dr_dxx = derivative_util.d_x_diffr_dx(x_, y_)
dr_dxy = derivative_util.d_x_diffr_dy(x_, y_)
dr_dyy = derivative_util.d_y_diffr_dy(x_, y_)
d_theta_dxx = derivative_util.d_phi_dxx(x_, y_)
d_theta_dyy = derivative_util.d_phi_dyy(x_, y_)
d_theta_dxy = derivative_util.d_phi_dxy(x_, y_)
f_xx = d_phi_dr2 * dr_dx**2 + d_phi_dr * dr_dxx + d_phi_d_theta2 * d_theta_dx**2 + d_phi_d_theta * d_theta_dxx + 2 * d_phi_dr_dtheta * dr_dx * d_theta_dx
f_yy = d_phi_dr2 * dr_dy**2 + d_phi_dr * dr_dyy + d_phi_d_theta2 * d_theta_dy**2 + d_phi_d_theta * d_theta_dyy + 2 * d_phi_dr_dtheta * dr_dy * d_theta_dy
f_xy = d_phi_dr2 * dr_dx * dr_dy + d_phi_dr * dr_dxy + d_phi_d_theta2 * d_theta_dx * d_theta_dy + d_phi_d_theta * d_theta_dxy + d_phi_dr_dtheta * dr_dx * d_theta_dy + d_phi_dr_dtheta * dr_dy * d_theta_dx
return f_xx * coeff, f_xy * coeff, f_xy * coeff, f_yy * coeff
def test_differentails(self):
x_, y_ = 1., 1
n_sersic = 2.
R_sersic = 1.
k_eff = 0.2
r = np.sqrt(x_**2 + y_**2)
d_alpha_dr = self.sersic.d_alpha_dr(x_, y_, n_sersic, R_sersic, k_eff)
alpha = self.sersic.alpha_abs(x_, y_, n_sersic, R_sersic, k_eff)
f_xx_ = d_alpha_dr * calc_util.d_r_dx(
x_, y_) * x_ / r + alpha * calc_util.d_x_diffr_dx(x_, y_)
f_yy_ = d_alpha_dr * calc_util.d_r_dy(
x_, y_) * y_ / r + alpha * calc_util.d_y_diffr_dy(x_, y_)
f_xy_ = d_alpha_dr * calc_util.d_r_dy(
x_, y_) * x_ / r + alpha * calc_util.d_x_diffr_dy(x_, y_)
f_xx = (d_alpha_dr / r - alpha / r**2) * y_**2 / r + alpha / r
f_yy = (d_alpha_dr / r - alpha / r**2) * x_**2 / r + alpha / r
f_xy = (d_alpha_dr / r - alpha / r**2) * x_ * y_ / r
npt.assert_almost_equal(f_xx, f_xx_, decimal=10)
npt.assert_almost_equal(f_yy, f_yy_, decimal=10)
npt.assert_almost_equal(f_xy, f_xy_, decimal=10)