def test_occultations():
"""Test occultation light curves."""
# Let's do the l = 3 Earth
m = Map(3)
m.load_image('earth')
# Rotate the map about a random axis
ux = np.random.random()
uy = np.random.random() * (1 - ux)
uz = np.sqrt(1 - ux ** 2 - uy ** 2)
axis = [ux, uy, uz]
npts = 30
theta = np.linspace(0, 360, npts, endpoint=False)
# Small occultor
ro = 0.3
xo = np.linspace(-1 - ro - 0.1, 1 + ro + 0.1, npts)
yo = 0
# Analytical and numerical fluxes
sF = np.array(m.flux(axis=axis, theta=theta, xo=xo, yo=yo, ro=ro))
nF = np.array(m._flux_numerical(axis=axis, theta=theta, xo=xo, yo=yo,
ro=ro, tol=1e-6))
# Compute the (relative) error
error = np.max(np.abs(sF - nF))
# Our numerical integration scheme isn't the most accurate,
# so let's be lenient here!
assert error < 1e-2
for j, m in enumerate(range(lmax + 1)):
ax[-1, j].set_xlabel(r"$m = %d$" % m, labelpad=30, fontsize=12)
# Occultation params
y = Map(lmax)
ro = 0.25
xo = np.linspace(-1.5, 1.5, nt)
xon = np.linspace(-1.5, 1.5, nn)
for yo, zorder, color in zip([0.25, 0.75], [1, 0], ['C0', 'C1']):
for i, l in enumerate(range(lmax + 1)):
for j, m in enumerate(range(l + 1)):
y.reset()
y.set_coeff(l, m, 1)
flux = y.flux(axis=[1, 0, 0], theta=0, xo=xo, yo=yo, ro=ro)
ax[i, j].plot(xo, flux, lw=1, zorder=zorder, color=color)
fluxn = y._flux_numerical(axis=[1, 0, 0], theta=0, xo=xon,
yo=yo, ro=ro, tol=1e-5)
ax[i, j].plot(xon, fluxn, '.', ms=2, zorder=zorder, color=color)
# Hack a legend
axleg = pl.axes([0.7, 0.7, 0.15, 0.15])
axleg.plot([0, 0], [1, 1], label=r'$y_0 = 0.25$')
axleg.plot([0, 0], [1, 1], label=r'$y_0 = 0.75$')
axleg.axis('off')
leg = axleg.legend(title=r'Occultations', fontsize=18)
leg.get_title().set_fontsize('20')
leg.get_frame().set_linewidth(0.0)
# Save!
fig.savefig("ylmlightcurves.pdf", bbox_inches='tight')
pl.close(fig)
# Rotate about this vector
ux = np.array([1., 0., 0.])
uy = np.array([0., 1., 0.])
y = Map(lmax)
theta = np.linspace(0, 360, nt, endpoint=False)
thetan = np.linspace(0, 360, nn, endpoint=False)
for i, l in enumerate(range(lmax + 1)):
for j, m in enumerate(range(l + 1)):
nnull = 0
for axis, zorder, color in zip([ux, uy], [1, 0], ['C0', 'C1']):
y.reset()
y.set_coeff(l, m, 1)
flux = y.flux(axis=axis, theta=theta)
ax[i, j].plot(theta, flux, lw=1, zorder=zorder, color=color)
fluxn = y._flux_numerical(axis=axis, theta=thetan, tol=1e-5)
ax[i, j].plot(thetan, fluxn, '.', ms=2, zorder=zorder, color=color)
if np.max(np.abs(flux)) < 1e-10:
nnull += 1
# If there's no light curve, make sure our plot range
# isn't too tight, as it will zoom in on floating point error
if nnull == 2:
ax[i, j].set_ylim(-1, 1)
# Force the scale for the constant map
ax[0, 0].set_ylim(0.886 + 1, 0.886 - 1)
# Hack a legend
axleg = pl.axes([0.7, 0.7, 0.15, 0.15])
axleg.plot([0, 0], [1, 1], label=r'$\vec{u} = \hat{x}$')
axleg.plot([0, 0], [1, 1], label=r'$\vec{u} = \hat{y}$')
axleg.axis('off')
for continent, label in zip(continents, labels):
m.load_image(continent)
m.rotate([0, 1, 0], -180)
F = m.flux(axis=[0, 1, 0], theta=theta)
F -= np.nanmin(F)
ax.plot(theta - 180, F, label=label)
# Compute and plot the total phase curve
m.load_image('earth.jpg')
m.rotate([0, 1, 0], -180)
total = m.flux(axis=[0, 1, 0], theta=theta)
total /= np.max(total)
ax.plot(theta - 180, total, 'k-', label='Total')
# Compute and plot the total phase curve (numerical)
totalnum = m._flux_numerical(axis=[0, 1, 0], theta=thetanum, tol=1e-5)
totalnum /= np.max(totalnum)
ax.plot(thetanum - 180, totalnum, 'k.')
# Appearance
ax.set_xlim(-180, 180)
ax.set_ylim(-0.05, 1.2)
ax.set_xticks([-180, -135, -90, -45, 0, 45, 90, 135, 180])
ax.set_yticks([0.0, 0.2, 0.4, 0.6, 0.8, 1.0])
ax.legend(loc='best', fontsize=11, ncol=2)
ax.set_xlabel('Sub-observer longitude [deg]', fontsize=18)
ax.set_ylabel('Normalized flux', fontsize=18)
for tick in ax.get_xticklabels() + ax.get_yticklabels():
tick.set_fontsize(16)
# Plot the earth images
# Say the occultation occurs over ~1 radian of the Earth's rotation
# That's equal to 24 / (2 * pi) hours
# (Remember, though, that `starry` accepts **DEGREES** as input!)
time = np.linspace(0, 24 / (2 * np.pi), npts)
timenum = np.linspace(0, 24 / (2 * np.pi), nptsnum)
theta0 = 0
theta = np.linspace(theta0, theta0 + 180. / np.pi, npts, endpoint=True)
thetanum = np.linspace(theta0, theta0 + 180. / np.pi, nptsnum, endpoint=True)
# Compute and plot the flux
F = m.flux(axis=[0, 1, 0], theta=theta, xo=xo, yo=yo, ro=ro)
F /= np.max(F)
ax_lc.plot(time, F, 'k-', label='Total')
# Compute and plot the numerical flux
Fnum = m._flux_numerical(axis=[0, 1, 0], theta=thetanum, xo=xonum,
yo=yonum, ro=ro, tol=1e-5)
Fnum /= np.max(Fnum)
ax_lc.plot(timenum, Fnum, 'k.')
# Plot the earth images
x, y = np.meshgrid(np.linspace(-1, 1, res), np.linspace(-1, 1, res))
for n in range(nim):
i = int(np.linspace(0, npts - 1, nim)[n])
I = [m.evaluate(axis=[0, 1, 0], theta=theta[i], x=x[j], y=y[j])
for j in range(res)]
ax_im[n].imshow(I, origin="lower", interpolation="none", cmap='plasma',
extent=(-1, 1, -1, 1))
xm = np.linspace(xo[i] - ro + 1e-5, xo[i] + ro - 1e-5, res)
ax_im[n].fill_between(xm, yo[i] - np.sqrt(ro ** 2 - (xm - xo[i]) ** 2),
yo[i] + np.sqrt(ro ** 2 - (xm - xo[i]) ** 2),
color='w')
