def test_convolve_flux_scaling():
"""Test flux scaling for Convolve.
"""
# decimal point to go to for parameter value comparisons
param_decimal = 12
test_flux = 17.9
test_sigma = 1.8
test_hlr = 1.9
# init with Gaussian and DeVauc only (should be ok given last tests)
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj *= 2.
np.testing.assert_almost_equal(
obj.flux, test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __imul__.")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj /= 2.
np.testing.assert_almost_equal(
obj.flux, test_flux / 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __idiv__.")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj2 = obj * 2.
# First test that original obj is unharmed...
np.testing.assert_almost_equal(
obj.flux, test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __rmul__ (original).")
# Then test new obj2 flux
np.testing.assert_almost_equal(
obj2.flux, test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __rmul__ (result).")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj2 = 2. * obj
# First test that original obj is unharmed...
np.testing.assert_almost_equal(
obj.flux, test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __mul__ (original).")
# Then test new obj2 flux
np.testing.assert_almost_equal(
obj2.flux, test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __mul__ (result).")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj2 = obj / 2.
# First test that original obj is unharmed...
np.testing.assert_almost_equal(
obj.flux, test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __div__ (original).")
# Then test new obj2 flux
np.testing.assert_almost_equal(
obj2.flux, test_flux / 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __div__ (result).")
def test_convolve_flux_scaling():
"""Test flux scaling for Convolve.
"""
import time
t1 = time.time()
# init with Gaussian and DeVauc only (should be ok given last tests)
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj *= 2.
np.testing.assert_almost_equal(
obj.getFlux(), test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __imul__.")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj /= 2.
np.testing.assert_almost_equal(
obj.getFlux(), test_flux / 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __idiv__.")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj2 = obj * 2.
# First test that original obj is unharmed... (also tests that .copy() is working)
np.testing.assert_almost_equal(
obj.getFlux(), test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __rmul__ (original).")
# Then test new obj2 flux
np.testing.assert_almost_equal(
obj2.getFlux(), test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __rmul__ (result).")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj2 = 2. * obj
# First test that original obj is unharmed... (also tests that .copy() is working)
np.testing.assert_almost_equal(
obj.getFlux(), test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __mul__ (original).")
# Then test new obj2 flux
np.testing.assert_almost_equal(
obj2.getFlux(), test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __mul__ (result).")
obj = galsim.Convolve(
[galsim.Gaussian(sigma=test_sigma, flux=np.sqrt(test_flux)),
galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=np.sqrt(test_flux))])
obj2 = obj / 2.
# First test that original obj is unharmed... (also tests that .copy() is working)
np.testing.assert_almost_equal(
obj.getFlux(), test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __div__ (original).")
# Then test new obj2 flux
np.testing.assert_almost_equal(
obj2.getFlux(), test_flux / 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __div__ (result).")
t2 = time.time()
print 'time for %s = %.2f'%(funcname(),t2-t1)
def test_largeshear():
"""Test the application of a large shear to a Sersic SBProfile against a known result.
"""
import time
t1 = time.time()
e1 = 0.0
e2 = 0.5
myShear = galsim.Shear(e1=e1, e2=e2)
# test the SBProfile version using applyShear
savedImg = galsim.fits.read(os.path.join(imgdir, "sersic_largeshear.fits"))
dx = 0.2
myImg = galsim.ImageF(savedImg.bounds, scale=dx)
myImg.setCenter(0,0)
devauc = galsim.DeVaucouleurs(flux=1, half_light_radius=1)
devauc.applyShear(myShear)
devauc.draw(myImg,scale=dx, normalization="surface brightness", use_true_center=False)
np.testing.assert_array_almost_equal(
myImg.array, savedImg.array, 5,
err_msg="Using GSObject applyShear disagrees with expected result")
devauc = galsim.DeVaucouleurs(flux=1, half_light_radius=1)
devauc2 = devauc.createSheared(myShear)
devauc2.draw(myImg,scale=dx, normalization="surface brightness", use_true_center=False)
np.testing.assert_array_almost_equal(
myImg.array, savedImg.array, 5,
err_msg="Using GSObject createSheared disagrees with expected result")
# Check with default_params
devauc = galsim.DeVaucouleurs(flux=1, half_light_radius=1, gsparams=default_params)
devauc.applyShear(myShear)
devauc.draw(myImg,scale=dx, normalization="surface brightness", use_true_center=False)
np.testing.assert_array_almost_equal(
myImg.array, savedImg.array, 5,
err_msg="Using GSObject applyShear with default_params disagrees with expected result")
devauc = galsim.DeVaucouleurs(flux=1, half_light_radius=1, gsparams=galsim.GSParams())
devauc.applyShear(myShear)
devauc.draw(myImg,scale=dx, normalization="surface brightness", use_true_center=False)
np.testing.assert_array_almost_equal(
myImg.array, savedImg.array, 5,
err_msg="Using GSObject applyShear with GSParams() disagrees with expected result")
# Test photon shooting.
# Convolve with a small gaussian to smooth out the central peak.
devauc2 = galsim.Convolve(devauc, galsim.Gaussian(sigma=0.3))
do_shoot(devauc2,myImg,"sheared DeVauc")
# Test kvalues.
# Testing a sheared devauc requires a rather large fft. What we really care about
# testing though is the accuracy of the applyShear function. So just shear a Gaussian here.
gauss = galsim.Gaussian(sigma=2.3)
gauss.applyShear(myShear)
do_kvalue(gauss, "sheared Gaussian")
t2 = time.time()
print 'time for %s = %.2f'%(funcname(),t2-t1)
def test_largeshear():
"""Test the application of a large shear to a Sersic profile against a known result.
"""
e1 = 0.0
e2 = 0.5
myShear = galsim.Shear(e1=e1, e2=e2)
savedImg = galsim.fits.read(os.path.join(imgdir, "sersic_largeshear.fits"))
dx = 0.2
myImg = galsim.ImageF(savedImg.bounds, scale=dx)
myImg.setCenter(0,0)
devauc = galsim.DeVaucouleurs(flux=1, half_light_radius=1)
devauc2 = devauc.shear(myShear)
devauc2.drawImage(myImg,scale=dx, method="sb", use_true_center=False)
np.testing.assert_array_almost_equal(
myImg.array, savedImg.array, 5,
err_msg="Using GSObject shear disagrees with expected result")
np.testing.assert_almost_equal(
myImg.array.max(), devauc2.max_sb, 5,
err_msg="sheared profile max_sb did not match maximum pixel value")
# Check with default_params
devauc = galsim.DeVaucouleurs(flux=1, half_light_radius=1, gsparams=default_params)
devauc = devauc.shear(myShear)
devauc.drawImage(myImg,scale=dx, method="sb", use_true_center=False)
np.testing.assert_array_almost_equal(
myImg.array, savedImg.array, 5,
err_msg="Using GSObject shear with default_params disagrees with expected result")
devauc = galsim.DeVaucouleurs(flux=1, half_light_radius=1, gsparams=galsim.GSParams())
devauc = devauc._shear(myShear)
devauc.drawImage(myImg,scale=dx, method="sb", use_true_center=False)
np.testing.assert_array_almost_equal(
myImg.array, savedImg.array, 5,
err_msg="Using GSObject shear with GSParams() disagrees with expected result")
# Convolve with a small gaussian to smooth out the central peak.
devauc2 = galsim.Convolve(devauc, galsim.Gaussian(sigma=0.3))
check_basic(devauc2, "sheared DeVauc")
# Test photon shooting.
do_shoot(devauc2,myImg,"sheared DeVauc")
# Test kvalues.
# Testing a sheared devauc requires a rather large fft. What we really care about
# testing though is the accuracy of the shear function. So just shear a Gaussian here.
gauss = galsim.Gaussian(sigma=2.3)
gauss = gauss.shear(myShear)
do_kvalue(gauss,myImg, "sheared Gaussian")
# Check picklability
do_pickle(gauss, lambda x: x.drawImage())
do_pickle(gauss)
do_pickle(gauss._sbp)
def makeBulge(redshift, SEDs):
bulgeG1, bulgeG2, mono_bulge_HLR = 0.12, 0.07, 0.5
mono_bulge = galsim.DeVaucouleurs(half_light_radius=mono_bulge_HLR)
bulge_SED = SEDs['CWW_E_ext'].atRedshift(redshift)
bulge = mono_bulge * bulge_SED
bulge = bulge.shear(g1=bulgeG1, g2=bulgeG2)
return bulge
def get_galsim_light_source(self, band_index, psf_sigma_degrees,
image_parameters):
def apply_shear_and_shift(galaxy):
return (galaxy.shear(
q=self._axis_ratio,
beta=(90. - self._gal_angle_deg) * galsim.degrees,
).shift(
self._common_fields.get_world_offset(
image_parameters).as_galsim_position()))
flux_nelec = (self._common_fields.get_flux_nmgy(band_index) *
image_parameters.band_nelec_per_nmgy[band_index])
half_light_radius_deg = self._half_light_radius_arcsec / ARCSEC_PER_DEGREE
exponential_profile = apply_shear_and_shift(
galsim.Exponential(
half_light_radius=half_light_radius_deg,
flux=flux_nelec * (1 - self._gal_frac_dev),
))
de_vaucouleurs_profile = apply_shear_and_shift(
galsim.DeVaucouleurs(
half_light_radius=half_light_radius_deg,
flux=flux_nelec * self._gal_frac_dev,
))
galaxy = exponential_profile + de_vaucouleurs_profile
psf = galsim.Gaussian(flux=1, sigma=psf_sigma_degrees)
return galsim.Convolve([galaxy, psf])
def _get_dev_model(self, spec):
obj = galsim.DeVaucouleurs(
half_light_radius=spec['hlr'],
flux=spec['Flux'],
)
return obj
def _get_object(self):
hlr, flux = self._get_hlr_flux()
disk_hlr = hlr
if self.g_pdf is None:
disk_g1, disk_g2 = 0.0, 0.0
else:
disk_g1, disk_g2 = self.g_pdf.sample2d()
all_obj = {}
if 'bulge' in self['pdfs']:
hlr_fac, fracdev, gfac, bulge_offset = self._get_bulge_stats()
bulge_hlr = disk_hlr * hlr_fac
bulge_g1, bulge_g2 = gfac * disk_g1, gfac * disk_g2
disk_flux = (1 - fracdev) * flux
bulge_flux = fracdev * flux
bulge = galsim.DeVaucouleurs(
half_light_radius=bulge_hlr,
flux=bulge_flux,
).shear(
g1=bulge_g1,
g2=bulge_g2,
).shift(
dx=bulge_offset[1],
dy=bulge_offset[0],
)
all_obj['bulge'] = bulge
else:
disk_flux = flux
disk = galsim.Exponential(
half_light_radius=disk_hlr,
flux=disk_flux,
).shear(
g1=disk_g1,
g2=disk_g2,
)
all_obj['disk'] = disk
if 'knots' in self['pdfs']:
nknots, knots_flux = self._get_knots_stats(disk_flux)
knots = galsim.RandomWalk(
npoints=nknots,
half_light_radius=disk_hlr,
flux=knots_flux,
).shear(g1=disk_g1, g2=disk_g2)
all_obj['knots'] = knots
obj_cen1, obj_cen2 = self.position_pdf.sample()
all_obj['cen'] = np.array([obj_cen1, obj_cen2])
return all_obj
def create_source(self, fractions, half_light_radius,
minor_major_axis_ratio, position_angle):
"""Create a model for the on-sky profile of a single source.
Size and shape parameter values for any component that is not
present (because its fraction is zero) are ignored.
Parameters
----------
fractions : array
Array of length 2 giving the disk and bulge fractions, respectively,
which must be in the range [0,1] (but this is not checked). If
their sum is less than one, the remainder is modeled as a point-like
component.
half_light_radius : array
Array of length 2 giving the disk and bulge half-light radii in
arcseconds, respectively.
minor_major_axis_ratio : array
Array of length 2 giving the dimensionless on-sky ellipse
minor / major axis ratio for the disk and bulge components,
respectively.
position_angle : array
Array of length 2 giving the position angle in degrees of the on-sky
disk and bluge ellipses, respectively. Angles are measured counter
clockwise relative to the +x axis.
Returns
-------
galsim.GSObject
A object representing the sum of all requested components with its
total flux normalized to one.
"""
# This is a no-op but still required to define the namespace.
import galsim
components = []
if fractions[0] > 0:
# Disk component
components.append(
galsim.Exponential(
flux=fractions[0],
half_light_radius=half_light_radius[0]).shear(
q=minor_major_axis_ratio[0],
beta=position_angle[0] * galsim.degrees))
if fractions[1] > 0:
components.append(
galsim.DeVaucouleurs(
flux=fractions[1],
half_light_radius=half_light_radius[1]).shear(
q=minor_major_axis_ratio[1],
beta=position_angle[1] * galsim.degrees))
star_fraction = 1 - fractions.sum()
if star_fraction > 0:
# Model a point-like source with a tiny (0.001 arcsec) Gaussian.
# TODO: sigma should be in arcsec here, not microns!
components.append(
galsim.Gaussian(flux=star_fraction,
sigma=1e-3 * self.image.scale))
# Combine the components and transform to focal-plane microns.
return galsim.Add(components, gsparams=self.gsparams)
def test_ne():
"""Test base.py GSObjects for not-equals."""
# Define some universal gsps
gsp = galsim.GSParams(maxk_threshold=1.1e-3, folding_threshold=5.1e-3)
# Sersic. Params include n, half_light_radius, scale_radius, flux, trunc, flux_untruncated
# and gsparams.
# The following should all test unequal:
gals = [galsim.Sersic(n=1.1, half_light_radius=1.0),
galsim.Sersic(n=1.2, half_light_radius=1.0),
galsim.Sersic(n=1.1, half_light_radius=1.1),
galsim.Sersic(n=1.1, scale_radius=1.0),
galsim.Sersic(n=1.1, half_light_radius=1.0, flux=1.1),
galsim.Sersic(n=1.1, half_light_radius=1.0, trunc=1.8),
galsim.Sersic(n=1.1, half_light_radius=1.0, trunc=1.8, flux_untruncated=True),
galsim.Sersic(n=1.1, half_light_radius=1.0, gsparams=gsp)]
all_obj_diff(gals)
# DeVaucouleurs. Params include half_light_radius, scale_radius, flux, trunc, flux_untruncated,
# and gsparams.
# The following should all test unequal:
gals = [galsim.DeVaucouleurs(half_light_radius=1.0),
galsim.DeVaucouleurs(half_light_radius=1.1),
galsim.DeVaucouleurs(scale_radius=1.0),
galsim.DeVaucouleurs(half_light_radius=1.0, flux=1.1),
galsim.DeVaucouleurs(half_light_radius=1.0, trunc=2.0),
galsim.DeVaucouleurs(half_light_radius=1.0, trunc=2.0, flux_untruncated=True),
galsim.DeVaucouleurs(half_light_radius=1.0, gsparams=gsp)]
all_obj_diff(gals)
def test_knots_hlr():
"""
Create a random walk galaxy and test that the half light radius
is consistent with the requested value
Note for DeV profile we don't test npoints=3 because it fails
"""
# for checking accuracy, we need expected standard deviation of
# the result
interp_npts = np.array(
[6, 7, 8, 9, 10, 15, 20, 30, 50, 75, 100, 150, 200, 500, 1000])
interp_hlr = np.array([
7.511, 7.597, 7.647, 7.68, 7.727, 7.827, 7.884, 7.936, 7.974, 8.0,
8.015, 8.019, 8.031, 8.027, 8.043
]) / 8.0
interp_std = np.array([
2.043, 2.029, 1.828, 1.817, 1.67, 1.443, 1.235, 1.017, 0.8046, 0.6628,
0.5727, 0.4703, 0.4047, 0.255, 0.1851
]) / 8.0
hlr = 8.0
# test these npoints
npt_vals = [3, 10, 30, 60, 100, 1000]
# should be within 5 sigma
nstd = 5
# number of trials
ntrial_vals = [100] * len(npt_vals)
profs = [
galsim.Gaussian(half_light_radius=hlr),
galsim.Exponential(half_light_radius=hlr),
galsim.DeVaucouleurs(half_light_radius=hlr),
]
for prof in profs:
for ipts, npoints in enumerate(npt_vals):
# DeV profile will fail for npoints==3
if isinstance(prof, galsim.DeVaucouleurs) and npoints == 3:
continue
ntrial = ntrial_vals[ipts]
hlr_calc = np.zeros(ntrial)
for i in range(ntrial):
#rw=galsim.RandomKnots(npoints, hlr)
rw = galsim.RandomKnots(npoints, profile=prof)
hlr_calc[i] = rw.calculateHLR()
mn = hlr_calc.mean()
std_check = np.interp(npoints, interp_npts, interp_std * hlr)
mess = "hlr for npoints: %d outside of expected range" % npoints
assert abs(mn - hlr) < nstd * std_check, mess
def test_sersic_flux_scaling():
"""Test flux scaling for Sersic.
"""
# decimal point to go to for parameter value comparisons
param_decimal = 12
test_hlr = 1.8
test_flux = 17.9
test_sersic_trunc = [0., 8.5]
if __name__ != "__main__":
# If doing a pytest run, we don't actually need to do all 4 sersic n values.
# Two should be enough to notice if there is a problem, and the full list will be tested
# when running python test_base.py to try to diagnose the problem.
test_sersic_n = [1.5, -4]
else:
test_sersic_n = [1.5, 2.5, 4, -4] # -4 means use explicit DeVauc rather than n=4
# loop through sersic n
for test_n in test_sersic_n:
# loop through sersic truncation
for test_trunc in test_sersic_trunc:
# init with hlr and flux only (should be ok given last tests)
# n=-4 is code to use explicit DeVaucouleurs rather than Sersic(n=4).
# It should be identical.
if test_n == -4:
init_obj = galsim.DeVaucouleurs(half_light_radius=test_hlr, flux=test_flux,
trunc=test_trunc)
else:
init_obj = galsim.Sersic(test_n, half_light_radius=test_hlr, flux=test_flux,
trunc=test_trunc)
obj2 = init_obj * 2.
np.testing.assert_almost_equal(
init_obj.flux, test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __rmul__ (original).")
np.testing.assert_almost_equal(
obj2.flux, test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __rmul__ (result).")
obj2 = 2. * init_obj
np.testing.assert_almost_equal(
init_obj.flux, test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __mul__ (original).")
np.testing.assert_almost_equal(
obj2.flux, test_flux * 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __mul__ (result).")
obj2 = init_obj / 2.
np.testing.assert_almost_equal(
init_obj.flux, test_flux, decimal=param_decimal,
err_msg="Flux param inconsistent after __div__ (original).")
np.testing.assert_almost_equal(
obj2.flux, test_flux / 2., decimal=param_decimal,
err_msg="Flux param inconsistent after __div__ (result).")
def __init__(self, identifier, redshift, ab_magnitude, ri_color,
cosmic_shear_g1, cosmic_shear_g2, dx_arcsecs, dy_arcsecs,
beta_radians, disk_flux, disk_hlr_arcsecs, disk_q, bulge_flux,
bulge_hlr_arcsecs, bulge_q, agn_flux):
self.identifier = identifier
self.redshift = redshift
self.ab_magnitude = ab_magnitude
self.ri_color = ri_color
self.dx_arcsecs = dx_arcsecs
self.dy_arcsecs = dy_arcsecs
self.cosmic_shear_g1 = cosmic_shear_g1
self.cosmic_shear_g2 = cosmic_shear_g2
components = []
# Initialize second-moments tensor. Note that we can only add the tensors for the
# n = 1,4 components, as we do below, since they have the same centroid.
self.second_moments = np.zeros((2, 2))
total_flux = disk_flux + bulge_flux + agn_flux
self.disk_fraction = disk_flux / total_flux
self.bulge_fraction = bulge_flux / total_flux
if disk_flux > 0:
disk = galsim.Exponential(
flux=disk_flux, half_light_radius=disk_hlr_arcsecs).shear(
q=disk_q, beta=beta_radians * galsim.radians)
components.append(disk)
self.second_moments += self.disk_fraction * sersic_second_moments(
n=1, hlr=disk_hlr_arcsecs, q=disk_q, beta=beta_radians)
if bulge_flux > 0:
bulge = galsim.DeVaucouleurs(
flux=bulge_flux, half_light_radius=bulge_hlr_arcsecs).shear(
q=bulge_q, beta=beta_radians * galsim.radians)
components.append(bulge)
self.second_moments += self.bulge_fraction * sersic_second_moments(
n=1, hlr=bulge_hlr_arcsecs, q=bulge_q, beta=beta_radians)
# GalSim does not currently provide a "delta-function" component to model the AGN
# so we use a very narrow Gaussian. See this GalSim issue for details:
# https://github.com/GalSim-developers/GalSim/issues/533
if agn_flux > 0:
agn = galsim.Gaussian(flux=agn_flux, sigma=1e-8)
components.append(agn)
# Combine the components into our final profile.
self.profile = galsim.Add(components)
# Apply transforms to build the final model.
self.model = self.get_transformed_model()
# Shear the second moments, if necessary.
if self.cosmic_shear_g1 != 0 or self.cosmic_shear_g2 != 0:
self.second_moments = sheared_second_moments(
self.second_moments, self.cosmic_shear_g1,
self.cosmic_shear_g2)
def test_hsmparams():
"""Test the ability to set/change parameters that define how moments/shape estimation are done."""
import time
t1 = time.time()
# First make some profile, and make sure that we get the same answers when we specify default
# hsmparams or don't specify hsmparams at all.
default_hsmparams = galsim.hsm.HSMParams(nsig_rg=3.0,
nsig_rg2=3.6,
max_moment_nsig2=25.0,
regauss_too_small=1,
adapt_order=2,
max_mom2_iter=400,
num_iter_default=-1,
bound_correct_wt=0.25,
max_amoment=8000.,
max_ashift=15.,
ksb_moments_max=4,
failed_moments=-1000.)
bulge = galsim.DeVaucouleurs(half_light_radius = 0.3)
disk = galsim.Exponential(half_light_radius = 0.5)
disk.applyShear(e1=0.2, e2=-0.3)
psf = galsim.Kolmogorov(fwhm = 0.6)
pix = galsim.Pixel(0.18)
gal = bulge + disk # equal weighting, i.e., B/T=0.5
tot_gal = galsim.Convolve(gal, psf, pix)
tot_psf = galsim.Convolve(psf, pix)
tot_gal_image = tot_gal.draw(dx=0.18)
tot_psf_image = tot_psf.draw(dx=0.18)
res = tot_gal_image.FindAdaptiveMom()
res_def = tot_gal_image.FindAdaptiveMom(hsmparams = default_hsmparams)
assert(equal_hsmshapedata(res, res_def)), 'Moment outputs differ when using default HSMParams'
res2 = galsim.hsm.EstimateShear(tot_gal_image, tot_psf_image)
res2_def = galsim.hsm.EstimateShear(tot_gal_image, tot_psf_image, hsmparams = default_hsmparams)
assert(equal_hsmshapedata(res, res_def)), 'Shear outputs differ when using default HSMParams'
try:
# Then check failure modes: force it to fail by changing HSMParams.
new_params_niter = galsim.hsm.HSMParams(max_mom2_iter = res.moments_n_iter-1)
new_params_size = galsim.hsm.HSMParams(max_amoment = 0.3*res.moments_sigma**2)
np.testing.assert_raises(RuntimeError, galsim.hsm.FindAdaptiveMom, tot_gal_image,
hsmparams=new_params_niter)
np.testing.assert_raises(RuntimeError, galsim.hsm.EstimateShear, tot_gal_image,
tot_psf_image, hsmparams=new_params_size)
except ImportError:
print 'The assert_raises tests require nose'
t2 = time.time()
print 'time for %s = %.2f'%(funcname(),t2-t1)
def test_sersic_shoot():
"""Test Sersic with photon shooting. Particularly the flux of the final image.
"""
rng = galsim.BaseDeviate(1234)
obj = galsim.Sersic(n=1.5, half_light_radius=3.5, flux=1.e4)
im = galsim.Image(100, 100, scale=1)
im.setCenter(0, 0)
added_flux, photons = obj.drawPhot(im,
poisson_flux=False,
rng=rng.duplicate())
print('obj.flux = ', obj.flux)
print('added_flux = ', added_flux)
print('photon fluxes = ', photons.flux.min(), '..', photons.flux.max())
print('image flux = ', im.array.sum())
assert np.isclose(added_flux, obj.flux)
assert np.isclose(im.array.sum(), obj.flux)
photons2 = obj.makePhot(poisson_flux=False, rng=rng)
assert photons2 == photons, "Sersic makePhot not equivalent to drawPhot"
obj = galsim.DeVaucouleurs(half_light_radius=3.5, flux=1.e4)
# Need a larger image for devauc wings
im = galsim.Image(1000, 1000, scale=1)
im.setCenter(0, 0)
added_flux, photons = obj.drawPhot(im,
poisson_flux=False,
rng=rng.duplicate())
print('obj.flux = ', obj.flux)
print('added_flux = ', added_flux)
print('photon fluxes = ', photons.flux.min(), '..', photons.flux.max())
print('image flux = ', im.array.sum())
assert np.isclose(added_flux, obj.flux)
assert np.isclose(im.array.sum(), obj.flux)
photons2 = obj.makePhot(poisson_flux=False, rng=rng)
assert photons2 == photons, "Sersic makePhot not equivalent to drawPhot"
# Can do up to around n=6 with this image if hlr is smaller.
obj = galsim.Sersic(half_light_radius=0.9, n=6.2, flux=1.e4)
added_flux, photons = obj.drawPhot(im,
poisson_flux=False,
rng=rng.duplicate())
print('obj.flux = ', obj.flux)
print('added_flux = ', added_flux)
print('photon fluxes = ', photons.flux.min(), '..', photons.flux.max())
print('image flux = ', im.array.sum())
assert np.isclose(added_flux, obj.flux)
assert np.isclose(im.array.sum(), obj.flux)
photons2 = obj.makePhot(poisson_flux=False, rng=rng)
assert photons2 == photons, "Sersic makePhot not equivalent to drawPhot"
def test_devaucouleurs():
"""Test various ways to build a DeVaucouleurs
"""
config = {
'gal1' : { 'type' : 'DeVaucouleurs' , 'half_light_radius' : 2 },
'gal2' : { 'type' : 'DeVaucouleurs' , 'half_light_radius' : 1.7, 'flux' : 100 },
'gal3' : { 'type' : 'DeVaucouleurs' , 'half_light_radius' : 3.5, 'flux' : 1.e6,
'ellip' : { 'type' : 'QBeta' , 'q' : 0.6, 'beta' : 0.39 * galsim.radians }
},
'gal4' : { 'type' : 'DeVaucouleurs' , 'half_light_radius' : 1, 'flux' : 50,
'dilate' : 3, 'ellip' : galsim.Shear(e1=0.3),
'rotate' : 12 * galsim.degrees,
'magnify' : 1.03, 'shear' : galsim.Shear(g1=0.03, g2=-0.05),
'shift' : { 'type' : 'XY', 'x' : 0.7, 'y' : -1.2 }
},
'gal5' : { 'type' : 'DeVaucouleurs' , 'half_light_radius' : 1, 'flux' : 50,
'gsparams' : { 'folding_threshold' : 1.e-4 }
}
}
gal1a = galsim.config.BuildGSObject(config, 'gal1')[0]
gal1b = galsim.DeVaucouleurs(half_light_radius = 2)
gsobject_compare(gal1a, gal1b)
gal2a = galsim.config.BuildGSObject(config, 'gal2')[0]
gal2b = galsim.DeVaucouleurs(half_light_radius = 1.7, flux = 100)
gsobject_compare(gal2a, gal2b)
gal3a = galsim.config.BuildGSObject(config, 'gal3')[0]
gal3b = galsim.DeVaucouleurs(half_light_radius = 3.5, flux = 1.e6)
gal3b = gal3b.shear(q = 0.6, beta = 0.39 * galsim.radians)
gsobject_compare(gal3a, gal3b)
gal4a = galsim.config.BuildGSObject(config, 'gal4')[0]
gal4b = galsim.DeVaucouleurs(half_light_radius = 1, flux = 50)
gal4b = gal4b.dilate(3).shear(e1 = 0.3).rotate(12 * galsim.degrees).magnify(1.03)
gal4b = gal4b.shear(g1 = 0.03, g2 = -0.05).shift(dx = 0.7, dy = -1.2)
gsobject_compare(gal4a, gal4b)
gal5a = galsim.config.BuildGSObject(config, 'gal5')[0]
gsparams = galsim.GSParams(folding_threshold=1.e-4)
gal5b = galsim.DeVaucouleurs(half_light_radius=1, flux=50, gsparams=gsparams)
gsobject_compare(gal5a, gal5b, conv=galsim.Gaussian(sigma=1))
try:
# Make sure they don't match when using the default GSParams
gal5c = galsim.DeVaucouleurs(half_light_radius=1, flux=50)
np.testing.assert_raises(AssertionError,gsobject_compare, gal5a, gal5c,
conv=galsim.Gaussian(sigma=1))
except ImportError:
print('The assert_raises tests require nose')
def render_galaxy(
self,
galaxy_params: Tensor,
psf: galsim.GSObject,
slen: int,
offset: Optional[Tensor] = None,
) -> Tensor:
assert offset is None or offset.shape == (2, )
if isinstance(galaxy_params, Tensor):
galaxy_params = galaxy_params.cpu().detach()
total_flux, disk_frac, beta_radians, disk_q, a_d, bulge_q, a_b = galaxy_params
bulge_frac = 1 - disk_frac
disk_flux = total_flux * disk_frac
bulge_flux = total_flux * bulge_frac
components = []
if disk_flux > 0:
b_d = a_d * disk_q
disk_hlr_arcsecs = np.sqrt(a_d * b_d)
disk = galsim.Exponential(
flux=disk_flux, half_light_radius=disk_hlr_arcsecs).shear(
q=disk_q,
beta=beta_radians * galsim.radians,
)
components.append(disk)
if bulge_flux > 0:
b_b = bulge_q * a_b
bulge_hlr_arcsecs = np.sqrt(a_b * b_b)
bulge = galsim.DeVaucouleurs(
flux=bulge_flux, half_light_radius=bulge_hlr_arcsecs).shear(
q=bulge_q, beta=beta_radians * galsim.radians)
components.append(bulge)
galaxy = galsim.Add(components)
gal_conv = galsim.Convolution(galaxy, psf)
offset = offset if offset is None else offset.numpy()
image = gal_conv.drawImage(nx=slen,
ny=slen,
method="auto",
scale=self.pixel_scale,
offset=offset)
return torch.from_numpy(image.array).reshape(1, slen, slen)
def _get_bd_model(self, spec):
rng = self.rng
flux = spec['Flux']
fracdev = rng.uniform(low=0.0, high=1.0)
bulge_flux = fracdev * flux
disk_flux = (1.0 - fracdev) * flux
disk_hlr = spec['hlr']
if 'bulge_size_factor' in spec:
frange = spec['bulge_size_factor']['range']
bulge_hlr = disk_hlr * rng.uniform(
low=frange[0],
high=frange[1],
)
else:
bulge_hlr = disk_hlr
if 'knots' in spec:
disk_flux, knot_flux = self._split_flux_with_knots(spec, disk_flux)
disk = galsim.Exponential(
half_light_radius=disk_hlr,
flux=disk_flux,
)
bulge = galsim.DeVaucouleurs(
half_light_radius=bulge_hlr,
flux=bulge_flux,
)
if 'knots' in spec:
knots = self._get_knots(spec, disk_hlr, knot_flux)
disk = galsim.Add([disk, knots])
disk = self._add_ellipticity(disk, spec)
bulge = self._add_ellipticity(bulge, spec)
return galsim.Add([disk, bulge])
def main():
p = get_params()
rng = galsim.UniformDeviate(p.random_seed)
#where to save images
image_dir = os.path.join('/home', 'ckrawiec', 'sims', 'images')
target_file_name = "stamps_{0}_.fits".format(p.id)
template_file_name = "template_stamps_{0}_.fits".format(p.id)
if p.noise_suppression == False:
gal_name = os.path.splitext(target_file_name)
else:
gal_name = os.path.splitext(template_file_name)
#initial noise
noise = galsim.GaussianNoise(rng)
#create test image to determine noise level
if p.noise_suppression == False:
test_psf = galsim.Moffat(3.5,
half_light_radius=p.psf_hlr * p.pixel_scale)
test_psf = test_psf.shear(e2=p.psf_e2)
test_bulge = galsim.DeVaucouleurs(half_light_radius=(
(p.gal_hlr_max - p.gal_hlr_min) / 2. + p.gal_hlr_min) *
p.pixel_scale)
test_disk = galsim.Exponential(half_light_radius=(
(p.gal_hlr_max - p.gal_hlr_min) / 2. + p.gal_hlr_min) *
p.pixel_scale)
test_gal = 0.5 * test_bulge + 0.5 * test_disk
test_gal = test_gal.withFlux(p.gal_flux_min)
test_image = galsim.ImageF(p.stamp_size,
p.stamp_size,
scale=p.pixel_scale)
test_final = galsim.Convolve([test_psf, test_gal])
test_final.drawImage(test_image)
noise_var = test_image.addNoiseSNR(noise,
p.gal_snr_min,
preserve_flux=True)
print noise_var
#final noise
noise = galsim.GaussianNoise(rng, sigma=np.sqrt(noise_var))
#make galaxy image
gal_image = galsim.ImageF(p.nx_tiles * p.stamp_size,
p.ny_tiles * p.stamp_size,
scale=p.pixel_scale)
#make ellipticity distribution from sigma
ellip_dist = BobsEDist(p.gal_ellip_sigma, rng)
for ifile in range(p.n_files):
#all files have same psf
psf = galsim.Moffat(3.5, half_light_radius=p.psf_hlr * p.pixel_scale)
psf = psf.shear(e2=p.psf_e2)
psf_image = galsim.ImageF(p.stamp_size,
p.stamp_size,
scale=p.pixel_scale)
psf.drawImage(psf_image)
for iy in range(p.ny_tiles):
for ix in range(p.nx_tiles):
b = galsim.BoundsI(ix * p.stamp_size + 1,
(ix + 1) * p.stamp_size,
iy * p.stamp_size + 1,
(iy + 1) * p.stamp_size)
sub_gal_image = gal_image[b]
hlr = (rng() * (p.gal_hlr_max - p.gal_hlr_min) +
p.gal_hlr_min) * p.pixel_scale
flux = rng() * (p.gal_flux_max -
p.gal_flux_min) + p.gal_flux_min
bulge_frac = rng()
e1, e2 = ellip_dist.sample()
#galaxy = ExponentialDisk + DeVaucouleurs
this_bulge = galsim.DeVaucouleurs(half_light_radius=hlr)
this_disk = galsim.Exponential(half_light_radius=hlr)
#same ellipticity
this_bulge = this_bulge.shear(e1=e1, e2=e2)
this_disk = this_disk.shear(e1=e1, e2=e2)
#Apply a shift in disk center within one pixel
shift_r = p.pixel_scale / 2.
dx = shift_r * (rng() * 2. - 1.)
dy = shift_r * (rng() * 2. - 1.)
this_disk = this_disk.shift(dx, dy)
#Apply a shift in bulge center within circle of radius hlr
theta = rng() * 2. * np.pi
r = rng() * hlr
dx = r * np.cos(theta)
dy = r * np.sin(theta)
this_bulge = this_bulge.shift(dx, dy)
this_gal = bulge_frac * this_bulge + (1 -
bulge_frac) * this_disk
this_gal = this_gal.withFlux(flux)
#All galaxies have same applied shear
this_gal = this_gal.shear(g1=p.g1, g2=p.g2)
final = galsim.Convolve([psf, this_gal])
final.drawImage(sub_gal_image)
if p.noise_suppression == False:
sub_gal_image.addNoise(noise)
gal_file = os.path.join(
image_dir,
''.join([gal_name[0],
str(ifile + 1).zfill(2), gal_name[1]]))
psf_file = os.path.join(
image_dir, ''.join([gal_name[0],
str(ifile + 1).zfill(2), '.psf']))
gal_image.write(gal_file)
psf_image.write(psf_file)
if (abs((e10[i]**2) * (e20[i]**2)) > 1.0):
e10[i] = 0.0
e20[i] = 0.0
gsparams=galsim.GSParams(folding_threshold=1.e-2,maxk_threshold=2.e-3,\
xvalue_accuracy=1.e-4,kvalue_accuracy=1.e-4,\
shoot_accuracy=1.e-4,minimum_fft_size=64)
#psf1=galsim.Moffat(fwhm=psf_fwhm[0],beta=2.5,gsparams=gsparams) #to be continue
#psf1=psf1.shear(e1=e1_psf,e2=e2_psf)
psf1 = galsim.Gaussian(fwhm=psf_fwhm[0], gsparams=gsparams)
#psf1=galsim.Kolmogorov(fwhm=psf_fwhm[0],gsparams=gsparams)
gal1 = galsim.Gaussian(half_light_radius=2, gsparams=gsparams)
gal2 = galsim.Exponential(half_light_radius=1, gsparams=gsparams)
gal3 = galsim.DeVaucouleurs(half_light_radius=1, gsparams=gsparams)
gal4 = galsim.Sersic(half_light_radius=1, n=2.5,
gsparams=gsparams) #to be continue
psf = psf1
final_epsf_image = psf1.drawImage(scale=pixel_scale)
gal = [gal1, gal2, gal3, gal4]
for i in range(m):
BJe1array = [[], [], [], []]
BJe2array = [[], [], [], []]
RGe1array = [[], [], [], []]
RGe2array = [[], [], [], []]
Me1array = [[], [], [], []]
Me2array = [[], [], [], []]
for j in range(4):
for p in range(2):
of the LSST stack. But it's still better to save the script as
well, even if it can't usually be run.
"""
import galsim
import lsst.shapelet.tractor
GALAXY_RADIUS = 8.0
PSF_SIGMA = 2.0
E1 = 0.3
E2 = -0.2
PROFILES = [
("exp", galsim.Exponential(half_light_radius=GALAXY_RADIUS), 9, 8),
("ser2", galsim.Sersic(n=2.0, half_light_radius=GALAXY_RADIUS), 9, 8),
("ser3", galsim.Sersic(n=3.0, half_light_radius=GALAXY_RADIUS), 9, 8),
("dev", galsim.DeVaucouleurs(half_light_radius=GALAXY_RADIUS), 9, 8),
]
MAKE_COMPONENT_IMAGES = False
def makeGaussian(flux, e1, e2, sigma):
g = galsim.Gaussian(flux=flux, sigma=sigma)
g.applyShear(e1=e1, e2=e2)
return g
def main():
for profile, exactGal, nComponents, maxRadius in PROFILES:
exactGal.applyShear(e1=E1, e2=E2)
psf = galsim.Gaussian(sigma=PSF_SIGMA)
def test_flip():
"""Test several ways to flip a profile
"""
# The Shapelet profile has the advantage of being fast and not circularly symmetric, so
# it is a good test of the actual code for doing the flips (in SBTransform).
# But since the bug Rachel reported in #645 was actually in SBInterpolatedImage
# (one calculation implicitly assumed dx > 0), it seems worthwhile to run through all the
# classes to make sure we hit everything with negative steps for dx and dy.
prof_list = [
galsim.Shapelet(sigma=0.17, order=2,
bvec=[1.7, 0.01,0.03, 0.29, 0.33, -0.18]),
]
if __name__ == "__main__":
image_dir = './real_comparison_images'
catalog_file = 'test_catalog.fits'
rgc = galsim.RealGalaxyCatalog(catalog_file, dir=image_dir)
# Some of these are slow, so only do the Shapelet test as part of the normal unit tests.
prof_list += [
galsim.Airy(lam_over_diam=0.17, flux=1.7),
galsim.Airy(lam_over_diam=0.17, obscuration=0.2, flux=1.7),
# Box gets rendered with real-space convolution. The default accuracy isn't quite
# enough to get the flip to match at 6 decimal places.
galsim.Box(0.17, 0.23, flux=1.7,
gsparams=galsim.GSParams(realspace_relerr=1.e-6)),
# Without being convolved by anything with a reasonable k cutoff, this needs
# a very large fft.
galsim.DeVaucouleurs(half_light_radius=0.17, flux=1.7),
# I don't really understand why this needs a lower maxk_threshold to work, but
# without it, the k-space tests fail.
galsim.Exponential(scale_radius=0.17, flux=1.7,
gsparams=galsim.GSParams(maxk_threshold=1.e-4)),
galsim.Gaussian(sigma=0.17, flux=1.7),
galsim.Kolmogorov(fwhm=0.17, flux=1.7),
galsim.Moffat(beta=2.5, fwhm=0.17, flux=1.7),
galsim.Moffat(beta=2.5, fwhm=0.17, flux=1.7, trunc=0.82),
galsim.OpticalPSF(lam_over_diam=0.17, obscuration=0.2, nstruts=6,
coma1=0.2, coma2=0.5, defocus=-0.1, flux=1.7),
# Like with Box, we need to increase the real-space convolution accuracy.
# This time lowering both relerr and abserr.
galsim.Pixel(0.23, flux=1.7,
gsparams=galsim.GSParams(realspace_relerr=1.e-6,
realspace_abserr=1.e-8)),
# Note: RealGalaxy should not be rendered directly because of the deconvolution.
# Here we convolve it by a Gaussian that is slightly larger than the original PSF.
galsim.Convolve([ galsim.RealGalaxy(rgc, index=0, flux=1.7), # "Real" RealGalaxy
galsim.Gaussian(sigma=0.08) ]),
galsim.Convolve([ galsim.RealGalaxy(rgc, index=1, flux=1.7), # "Fake" RealGalaxy
galsim.Gaussian(sigma=0.08) ]), # (cf. test_real.py)
galsim.Spergel(nu=-0.19, half_light_radius=0.17, flux=1.7),
galsim.Spergel(nu=0., half_light_radius=0.17, flux=1.7),
galsim.Spergel(nu=0.8, half_light_radius=0.17, flux=1.7),
galsim.Sersic(n=2.3, half_light_radius=0.17, flux=1.7),
galsim.Sersic(n=2.3, half_light_radius=0.17, flux=1.7, trunc=0.82),
# The shifts here caught a bug in how SBTransform handled the recentering.
# Two of the shifts (0.125 and 0.375) lead back to 0.0 happening on an integer
# index, which now works correctly.
galsim.Sum([ galsim.Gaussian(sigma=0.17, flux=1.7).shift(-0.2,0.125),
galsim.Exponential(scale_radius=0.23, flux=3.1).shift(0.375,0.23)]),
galsim.TopHat(0.23, flux=1.7),
# Box and Pixel use real-space convolution. Convolve with a Gaussian to get fft.
galsim.Convolve([ galsim.Box(0.17, 0.23, flux=1.7).shift(-0.2,0.1),
galsim.Gaussian(sigma=0.09) ]),
galsim.Convolve([ galsim.TopHat(0.17, flux=1.7).shift(-0.275,0.125),
galsim.Gaussian(sigma=0.09) ]),
# Test something really crazy with several layers worth of transformations
galsim.Convolve([
galsim.Sum([
galsim.Gaussian(sigma=0.17, flux=1.7).shear(g1=0.1,g2=0.2).shift(2,3),
galsim.Kolmogorov(fwhm=0.33, flux=3.9).transform(0.31,0.19,-0.23,0.33) * 88.,
galsim.Box(0.11, 0.44, flux=4).rotate(33 * galsim.degrees) / 1.9
]).shift(-0.3,1),
galsim.AutoConvolve(galsim.TopHat(0.5).shear(g1=0.3,g2=0)).rotate(3*galsim.degrees),
(galsim.AutoCorrelate(galsim.Box(0.2, 0.3)) * 11).shift(3,2).shift(2,-3) * 0.31
]).shift(0,0).transform(0,-1,-1,0).shift(-1,1)
]
s = galsim.Shear(g1=0.11, g2=-0.21)
s1 = galsim.Shear(g1=0.11, g2=0.21) # Appropriate for the flips around x and y axes
s2 = galsim.Shear(g1=-0.11, g2=-0.21) # Appropriate for the flip around x=y
# Also use shears with just a g1 to get dx != dy, but dxy, dyx = 0.
q = galsim.Shear(g1=0.11, g2=0.)
q1 = galsim.Shear(g1=0.11, g2=0.) # Appropriate for the flips around x and y axes
q2 = galsim.Shear(g1=-0.11, g2=0.) # Appropriate for the flip around x=y
decimal=6 # Oddly, these aren't as precise as I would have expected.
# Even when we only go to this many digits of accuracy, the Exponential needed
# a lower than default value for maxk_threshold.
im = galsim.ImageD(16,16, scale=0.05)
for prof in prof_list:
print('prof = ',prof)
# Not all profiles are expected to have a max_sb value close to the maximum pixel value,
# so mark the ones where we don't want to require this to be true.
close_maxsb = True
name = str(prof)
if ('DeVauc' in name or 'Sersic' in name or 'Spergel' in name or
'Optical' in name or 'shift' in name):
close_maxsb = False
# Make sure we hit all 4 fill functions.
# image_x uses fillXValue with izero, jzero
# image_x1 uses fillXValue with izero, jzero, and unequal dx,dy
# image_x2 uses fillXValue with dxy, dyx
# image_k uses fillKValue with izero, jzero
# image_k1 uses fillKValue with izero, jzero, and unequal dx,dy
# image_k2 uses fillKValue with dxy, dyx
image_x = prof.drawImage(image=im.copy(), method='no_pixel')
image_x1 = prof.shear(q).drawImage(image=im.copy(), method='no_pixel')
image_x2 = prof.shear(s).drawImage(image=im.copy(), method='no_pixel')
image_k = prof.drawImage(image=im.copy())
image_k1 = prof.shear(q).drawImage(image=im.copy())
image_k2 = prof.shear(s).drawImage(image=im.copy())
if close_maxsb:
np.testing.assert_allclose(
image_x.array.max(), prof.max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image_x1.array.max(), prof.shear(q).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image_x2.array.max(), prof.shear(s).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
# Flip around y axis (i.e. x -> -x)
flip1 = prof.transform(-1, 0, 0, 1)
image2_x = flip1.drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x.array, image2_x.array[:,::-1], decimal=decimal,
err_msg="Flipping image around y-axis failed x test")
image2_x1 = flip1.shear(q1).drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x1.array, image2_x1.array[:,::-1], decimal=decimal,
err_msg="Flipping image around y-axis failed x1 test")
image2_x2 = flip1.shear(s1).drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x2.array, image2_x2.array[:,::-1], decimal=decimal,
err_msg="Flipping image around y-axis failed x2 test")
image2_k = flip1.drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k.array, image2_k.array[:,::-1], decimal=decimal,
err_msg="Flipping image around y-axis failed k test")
image2_k1 = flip1.shear(q1).drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k1.array, image2_k1.array[:,::-1], decimal=decimal,
err_msg="Flipping image around y-axis failed k1 test")
image2_k2 = flip1.shear(s1).drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k2.array, image2_k2.array[:,::-1], decimal=decimal,
err_msg="Flipping image around y-axis failed k2 test")
if close_maxsb:
np.testing.assert_allclose(
image2_x.array.max(), flip1.max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image2_x1.array.max(), flip1.shear(q).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image2_x2.array.max(), flip1.shear(s).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
# Flip around x axis (i.e. y -> -y)
flip2 = prof.transform(1, 0, 0, -1)
image2_x = flip2.drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x.array, image2_x.array[::-1,:], decimal=decimal,
err_msg="Flipping image around x-axis failed x test")
image2_x1 = flip2.shear(q1).drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x1.array, image2_x1.array[::-1,:], decimal=decimal,
err_msg="Flipping image around x-axis failed x1 test")
image2_x2 = flip2.shear(s1).drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x2.array, image2_x2.array[::-1,:], decimal=decimal,
err_msg="Flipping image around x-axis failed x2 test")
image2_k = flip2.drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k.array, image2_k.array[::-1,:], decimal=decimal,
err_msg="Flipping image around x-axis failed k test")
image2_k1 = flip2.shear(q1).drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k1.array, image2_k1.array[::-1,:], decimal=decimal,
err_msg="Flipping image around x-axis failed k1 test")
image2_k2 = flip2.shear(s1).drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k2.array, image2_k2.array[::-1,:], decimal=decimal,
err_msg="Flipping image around x-axis failed k2 test")
if close_maxsb:
np.testing.assert_allclose(
image2_x.array.max(), flip2.max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image2_x1.array.max(), flip2.shear(q).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image2_x2.array.max(), flip2.shear(s).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
# Flip around x=y (i.e. y -> x, x -> y)
flip3 = prof.transform(0, 1, 1, 0)
image2_x = flip3.drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x.array, np.transpose(image2_x.array), decimal=decimal,
err_msg="Flipping image around x=y failed x test")
image2_x1 = flip3.shear(q2).drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x1.array, np.transpose(image2_x1.array), decimal=decimal,
err_msg="Flipping image around x=y failed x1 test")
image2_x2 = flip3.shear(s2).drawImage(image=im.copy(), method='no_pixel')
np.testing.assert_array_almost_equal(
image_x2.array, np.transpose(image2_x2.array), decimal=decimal,
err_msg="Flipping image around x=y failed x2 test")
image2_k = flip3.drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k.array, np.transpose(image2_k.array), decimal=decimal,
err_msg="Flipping image around x=y failed k test")
image2_k1 = flip3.shear(q2).drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k1.array, np.transpose(image2_k1.array), decimal=decimal,
err_msg="Flipping image around x=y failed k1 test")
image2_k2 = flip3.shear(s2).drawImage(image=im.copy())
np.testing.assert_array_almost_equal(
image_k2.array, np.transpose(image2_k2.array), decimal=decimal,
err_msg="Flipping image around x=y failed k2 test")
if close_maxsb:
np.testing.assert_allclose(
image2_x.array.max(), flip3.max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image2_x1.array.max(), flip3.shear(q).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
np.testing.assert_allclose(
image2_x2.array.max(), flip3.shear(s).max_sb*im.scale**2, rtol=0.2,
err_msg="max_sb did not match maximum pixel value")
do_pickle(prof, lambda x: x.drawImage(image=im.copy(), method='no_pixel'))
do_pickle(flip1, lambda x: x.drawImage(image=im.copy(), method='no_pixel'))
do_pickle(flip2, lambda x: x.drawImage(image=im.copy(), method='no_pixel'))
do_pickle(flip3, lambda x: x.drawImage(image=im.copy(), method='no_pixel'))
do_pickle(prof)
do_pickle(flip1)
do_pickle(flip2)
do_pickle(flip3)
def main(argv):
# Where to find and output data
path, filename = os.path.split(__file__)
datapath = os.path.abspath(os.path.join(path, "data/"))
outpath = os.path.abspath(os.path.join(path, "output/"))
# In non-script code, use getLogger(__name__) at module scope instead.
logging.basicConfig(format="%(message)s",
level=logging.INFO,
stream=sys.stdout)
logger = logging.getLogger("demo12")
# initialize (pseudo-)random number generator
random_seed = 1234567
rng = galsim.BaseDeviate(random_seed)
# read in SEDs
SED_names = ['CWW_E_ext', 'CWW_Sbc_ext', 'CWW_Scd_ext', 'CWW_Im_ext']
SEDs = {}
for SED_name in SED_names:
SED_filename = os.path.join(galsim.meta_data.share_dir,
'{0}.sed'.format(SED_name))
# Here we create some galsim.SED objects to hold star or galaxy spectra. The most
# convenient way to create realistic spectra is to read them in from a two-column ASCII
# file, where the first column is wavelength and the second column is flux. Wavelengths in
# the example SED files are in Angstroms, flux in flambda. We use a set of files that are
# distributed with GalSim in the share/ directory.
SED = galsim.SED(SED_filename, wave_type='Ang', flux_type='flambda')
# The normalization of SEDs affects how many photons are eventually drawn into an image.
# One way to control this normalization is to specify the flux density in photons per nm
# at a particular wavelength. For example, here we normalize such that the photon density
# is 1 photon per nm at 500 nm.
SEDs[SED_name] = SED.withFluxDensity(target_flux_density=1.0,
wavelength=500)
logger.debug('Successfully read in SEDs')
# read in the LSST filters
filter_names = 'ugrizy'
filters = {}
for filter_name in filter_names:
filter_filename = os.path.join(datapath,
'LSST_{0}.dat'.format(filter_name))
# Here we create some galsim.Bandpass objects to represent the filters we're observing
# through. These include the entire imaging system throughput including the atmosphere,
# reflective and refractive optics, filters, and the CCD quantum efficiency. These are
# also conveniently read in from two-column ASCII files where the first column is
# wavelength and the second column is dimensionless throughput. The example filter files
# units of nanometers for the wavelength type, so we specify that using the required
# `wave_type` argument.
filters[filter_name] = galsim.Bandpass(filter_filename, wave_type='nm')
# For speed, we can thin out the wavelength sampling of the filter a bit.
# In the following line, `rel_err` specifies the relative error when integrating over just
# the filter (however, this is not necessarily the relative error when integrating over the
# filter times an SED).
filters[filter_name] = filters[filter_name].thin(rel_err=1e-4)
logger.debug('Read in filters')
pixel_scale = 0.2 # arcseconds
#-----------------------------------------------------------------------------------------------
# Part A: chromatic de Vaucouleurs galaxy
# Here we create a chromatic version of a de Vaucouleurs profile using the Chromatic class.
# This class lets one create chromatic versions of any galsim GSObject class. The first
# argument is the GSObject instance to be chromaticized, and the second argument is the
# profile's SED.
logger.info('')
logger.info('Starting part A: chromatic De Vaucouleurs galaxy')
redshift = 0.8
mono_gal = galsim.DeVaucouleurs(half_light_radius=0.5)
SED = SEDs['CWW_E_ext'].atRedshift(redshift)
gal = galsim.Chromatic(mono_gal, SED)
# You can still shear, shift, and dilate the resulting chromatic object.
gal = gal.shear(g1=0.5, g2=0.3).dilate(1.05).shift((0.0, 0.1))
logger.debug('Created Chromatic')
# convolve with PSF to make final profile
PSF = galsim.Moffat(fwhm=0.6, beta=2.5)
final = galsim.Convolve([gal, PSF])
logger.debug('Created final profile')
# draw profile through LSST filters
gaussian_noise = galsim.GaussianNoise(rng, sigma=0.1)
for filter_name, filter_ in filters.iteritems():
img = galsim.ImageF(64, 64, scale=pixel_scale)
final.drawImage(filter_, image=img)
img.addNoise(gaussian_noise)
logger.debug('Created {0}-band image'.format(filter_name))
out_filename = os.path.join(outpath,
'demo12a_{0}.fits'.format(filter_name))
galsim.fits.write(img, out_filename)
logger.debug('Wrote {0}-band image to disk'.format(filter_name))
logger.info('Added flux for {0}-band image: {1}'.format(
filter_name, img.added_flux))
logger.info(
'You can display the output in ds9 with a command line that looks something like:'
)
logger.info(
'ds9 output/demo12a_*.fits -match scale -zoom 2 -match frame image &')
#-----------------------------------------------------------------------------------------------
# Part B: chromatic bulge+disk galaxy
logger.info('')
logger.info('Starting part B: chromatic bulge+disk galaxy')
redshift = 0.8
# make a bulge ...
mono_bulge = galsim.DeVaucouleurs(half_light_radius=0.5)
bulge_SED = SEDs['CWW_E_ext'].atRedshift(redshift)
# The `*` operator can be used as a shortcut for creating a chromatic version of a GSObject:
bulge = mono_bulge * bulge_SED
bulge = bulge.shear(g1=0.12, g2=0.07)
logger.debug('Created bulge component')
# ... and a disk ...
mono_disk = galsim.Exponential(half_light_radius=2.0)
disk_SED = SEDs['CWW_Im_ext'].atRedshift(redshift)
disk = mono_disk * disk_SED
disk = disk.shear(g1=0.4, g2=0.2)
logger.debug('Created disk component')
# ... and then combine them.
bdgal = 1.1 * (
0.8 * bulge + 4 * disk
) # you can add and multiply ChromaticObjects just like GSObjects
bdfinal = galsim.Convolve([bdgal, PSF])
# Note that at this stage, our galaxy is chromatic but our PSF is still achromatic. Part C)
# below will dive into chromatic PSFs.
logger.debug('Created bulge+disk galaxy final profile')
# draw profile through LSST filters
gaussian_noise = galsim.GaussianNoise(rng, sigma=0.02)
for filter_name, filter_ in filters.iteritems():
img = galsim.ImageF(64, 64, scale=pixel_scale)
bdfinal.drawImage(filter_, image=img)
img.addNoise(gaussian_noise)
logger.debug('Created {0}-band image'.format(filter_name))
out_filename = os.path.join(outpath,
'demo12b_{0}.fits'.format(filter_name))
galsim.fits.write(img, out_filename)
logger.debug('Wrote {0}-band image to disk'.format(filter_name))
logger.info('Added flux for {0}-band image: {1}'.format(
filter_name, img.added_flux))
logger.info(
'You can display the output in ds9 with a command line that looks something like:'
)
logger.info(
'ds9 -rgb -blue -scale limits -0.2 0.8 output/demo12b_r.fits -green -scale limits'
+
' -0.25 1.0 output/demo12b_i.fits -red -scale limits -0.25 1.0 output/demo12b_z.fits'
+ ' -zoom 2 &')
#-----------------------------------------------------------------------------------------------
# Part C: chromatic PSF
logger.info('')
logger.info('Starting part C: chromatic PSF')
redshift = 0.0
mono_gal = galsim.Exponential(half_light_radius=0.5)
SED = SEDs['CWW_Im_ext'].atRedshift(redshift)
# Here's another way to set the normalization of the SED. If we want 50 counts to be drawn
# when observing an object with this SED through the LSST g-band filter, for instance, then we
# can do:
SED = SED.withFlux(50.0, filters['g'])
# The flux drawn through other bands, which sample different parts of the SED and have different
# throughputs, will, of course, be different.
gal = mono_gal * SED
gal = gal.shear(g1=0.5, g2=0.3)
logger.debug('Created `Chromatic` galaxy')
# For a ground-based PSF, two chromatic effects are introduced by the atmosphere:
# (i) differential chromatic refraction (DCR), and (ii) wavelength-dependent seeing.
#
# DCR shifts the position of the PSF as a function of wavelength. Blue light is shifted
# toward the zenith slightly more than red light.
#
# Kolmogorov turbulence in the atmosphere leads to a seeing size (e.g., FWHM) that scales with
# wavelength to the (-0.2) power.
#
# The ChromaticAtmosphere function will attach both of these effects to a fiducial PSF at
# some fiducial wavelength.
# First we define a monochromatic PSF to be the fiducial PSF.
PSF_500 = galsim.Moffat(beta=2.5, fwhm=0.5)
# Then we use ChromaticAtmosphere to manipulate this fiducial PSF as a function of wavelength.
# ChromaticAtmosphere also needs to know the wavelength of the fiducial PSF, and the location
# and orientation of the object with respect to the zenith. This final piece of information
# can be specified in several ways (see the ChromaticAtmosphere docstring for all of them).
# Here are a couple ways: let's pretend our object is located near M101 on the sky, we observe
# it 1 hour before it transits and we're observing from Mauna Kea.
ra = galsim.HMS_Angle("14:03:13") # hours : minutes : seconds
dec = galsim.DMS_Angle("54:20:57") # degrees : minutes : seconds
m101 = galsim.CelestialCoord(ra, dec)
latitude = 19.8207 * galsim.degrees # latitude of Mauna Kea
HA = -1.0 * galsim.hours # Hour angle = one hour before transit
# Then we can compute the zenith angle and parallactic angle (which is is the position angle
# of the zenith measured from North through East) of this object:
za, pa = galsim.dcr.zenith_parallactic_angles(m101,
HA=HA,
latitude=latitude)
# And then finally, create the chromatic PSF
PSF = galsim.ChromaticAtmosphere(PSF_500,
500.0,
zenith_angle=za,
parallactic_angle=pa)
# We could have also just passed `m101`, `latitude` and `HA` to ChromaticAtmosphere directly:
PSF = galsim.ChromaticAtmosphere(PSF_500,
500.0,
obj_coord=m101,
latitude=latitude,
HA=HA)
# and proceed like normal.
# convolve with galaxy to create final profile
final = galsim.Convolve([gal, PSF])
logger.debug('Created chromatic PSF finale profile')
# Draw profile through LSST filters
gaussian_noise = galsim.GaussianNoise(rng, sigma=0.03)
for filter_name, filter_ in filters.iteritems():
img = galsim.ImageF(64, 64, scale=pixel_scale)
final.drawImage(filter_, image=img)
img.addNoise(gaussian_noise)
logger.debug('Created {0}-band image'.format(filter_name))
out_filename = os.path.join(outpath,
'demo12c_{0}.fits'.format(filter_name))
galsim.fits.write(img, out_filename)
logger.debug('Wrote {0}-band image to disk'.format(filter_name))
logger.info('Added flux for {0}-band image: {1}'.format(
filter_name, img.added_flux))
logger.info(
'You can display the output in ds9 with a command line that looks something like:'
)
logger.info(
'ds9 output/demo12c_*.fits -match scale -zoom 2 -match frame image -blink &'
)
def main(argv):
"""
Make a fits image cube where each frame has two images of the same galaxy drawn
with regular FFT convolution and with photon shooting.
We do this for 5 different PSFs and 5 different galaxies, each with 4 different (random)
fluxes, sizes, and shapes.
"""
logging.basicConfig(format="%(message)s",
level=logging.INFO,
stream=sys.stdout)
logger = logging.getLogger("demo7")
# To turn off logging:
#logger.propagate = False
# Define some parameters we'll use below.
# Make output directory if not already present.
if not os.path.isdir('output'):
os.mkdir('output')
file_name = os.path.join('output', 'cube_phot.fits.gz')
random_seed = 553728
sky_level = 1.e4 # ADU / arcsec^2
pixel_scale = 0.28 # arcsec
nx = 64
ny = 64
gal_flux_min = 1.e4 # Range for galaxy flux
gal_flux_max = 1.e5
gal_hlr_min = 0.3 # arcsec
gal_hlr_max = 1.3 # arcsec
gal_e_min = 0. # Range for ellipticity
gal_e_max = 0.8
psf_fwhm = 0.65 # arcsec
# This script is set up as a comparison between using FFTs for doing the convolutions and
# shooting photons. The two methods have trade-offs in speed and accuracy which vary
# with the kind of profile being drawn and the S/N of the object, among other factors.
# In addition, for each method, there are a number of parameters GalSim uses that control
# aspects of the calculation that further affect the speed and accuracy.
#
# We encapsulate these parameters with an object called GSParams. The default values
# are intended to be accurate enough for normal precision shear tests, without sacrificing
# too much speed.
#
# Any PSF or galaxy object can be given a gsparams argument on construction that can
# have different values to make the calculation more or less accurate (typically trading
# off for speed or memory).
#
# In this script, we adjust some of the values slightly, just to show you how it works.
# You could play around with these values and see what effect they have on the drawn images.
# Usually, it requires a pretty drastic change in these parameters for you to be able to
# notice the difference by eye. But subtle effects that may impact the shapes of galaxies
# can happen well before then.
# Type help(galsim.GSParams) for the complete list of parameters and more detailed
# documentation, including the default values for each parameter.
gsparams = galsim.GSParams(
alias_threshold=
1.e-2, # maximum fractional flux that may be aliased around edge of FFT
maxk_threshold=
2.e-3, # k-values less than this may be excluded off edge of FFT
xvalue_accuracy=
1.e-4, # approximations in real space aim to be this accurate
kvalue_accuracy=
1.e-4, # approximations in fourier space aim to be this accurate
shoot_accuracy=
1.e-4, # approximations in photon shooting aim to be this accurate
minimum_fft_size=64) # minimum size of ffts
logger.info('Starting demo script 7')
# Make the pixel:
pix = galsim.Pixel(xw=pixel_scale)
# Make the PSF profiles:
psf1 = galsim.Gaussian(fwhm=psf_fwhm, gsparams=gsparams)
psf2 = galsim.Moffat(fwhm=psf_fwhm, beta=2.4, gsparams=gsparams)
psf3_inner = galsim.Gaussian(fwhm=psf_fwhm, flux=0.8, gsparams=gsparams)
psf3_outer = galsim.Gaussian(fwhm=2 * psf_fwhm,
flux=0.2,
gsparams=gsparams)
psf3 = psf3_inner + psf3_outer
atmos = galsim.Gaussian(fwhm=psf_fwhm, gsparams=gsparams)
optics = galsim.OpticalPSF(lam_over_diam=0.6 * psf_fwhm,
obscuration=0.4,
defocus=0.1,
astig1=0.3,
astig2=-0.2,
coma1=0.2,
coma2=0.1,
spher=-0.3,
gsparams=gsparams)
psf4 = galsim.Convolve([atmos, optics
]) # Convolve inherits the gsparams from the first
# item in the list. (Or you can supply a gsparams
# argument explicitly if you want to override this.)
atmos = galsim.Kolmogorov(fwhm=psf_fwhm, gsparams=gsparams)
optics = galsim.Airy(lam_over_diam=0.3 * psf_fwhm, gsparams=gsparams)
psf5 = galsim.Convolve([atmos, optics])
psfs = [psf1, psf2, psf3, psf4, psf5]
psf_names = [
"Gaussian", "Moffat", "Double Gaussian", "OpticalPSF",
"Kolmogorov * Airy"
]
psf_times = [0, 0, 0, 0, 0]
psf_fft_times = [0, 0, 0, 0, 0]
psf_phot_times = [0, 0, 0, 0, 0]
# Make the galaxy profiles:
gal1 = galsim.Gaussian(half_light_radius=1, gsparams=gsparams)
gal2 = galsim.Exponential(half_light_radius=1, gsparams=gsparams)
gal3 = galsim.DeVaucouleurs(half_light_radius=1, gsparams=gsparams)
gal4 = galsim.Sersic(half_light_radius=1, n=2.5, gsparams=gsparams)
bulge = galsim.Sersic(half_light_radius=0.7, n=3.2, gsparams=gsparams)
disk = galsim.Sersic(half_light_radius=1.2, n=1.5, gsparams=gsparams)
gal5 = 0.4 * bulge + 0.6 * disk # Net half-light radius is only approximate for this one.
gals = [gal1, gal2, gal3, gal4, gal5]
gal_names = [
"Gaussian", "Exponential", "Devaucouleurs", "n=2.5 Sersic",
"Bulge + Disk"
]
gal_times = [0, 0, 0, 0, 0]
gal_fft_times = [0, 0, 0, 0, 0]
gal_phot_times = [0, 0, 0, 0, 0]
# Other times to keep track of:
setup_times = 0
fft_times = 0
phot_times = 0
noise_times = 0
# Loop over combinations of psf, gal, and make 4 random choices for flux, size, shape.
all_images = []
k = 0
for ipsf in range(len(psfs)):
psf = psfs[ipsf]
psf_name = psf_names[ipsf]
for igal in range(len(gals)):
gal = gals[igal]
gal_name = gal_names[igal]
for i in range(4):
logger.debug('Start work on image %d', i)
t1 = time.time()
# Initialize the random number generator we will be using.
rng = galsim.UniformDeviate(random_seed + k)
# Get a new copy, we'll want to keep the original unmodified.
gal1 = gal.copy()
# Generate random variates:
flux = rng() * (gal_flux_max - gal_flux_min) + gal_flux_min
gal1.setFlux(flux)
hlr = rng() * (gal_hlr_max - gal_hlr_min) + gal_hlr_min
gal1.applyDilation(hlr)
beta_ellip = rng() * 2 * math.pi * galsim.radians
ellip = rng() * (gal_e_max - gal_e_min) + gal_e_min
gal_shape = galsim.Shear(e=ellip, beta=beta_ellip)
gal1.applyShear(gal_shape)
# Build the final object by convolving the galaxy, PSF and pixel response.
final = galsim.Convolve([psf, pix, gal1])
# For photon shooting, need a version without the pixel (see below).
final_nopix = galsim.Convolve([psf, gal1])
# Create the large, double width output image
image = galsim.ImageF(2 * nx + 2, ny)
# Rather than provide a dx= argument to the draw commands, we can also
# set the pixel scale in the image itself with setScale.
image.setScale(pixel_scale)
# Assign the following two "ImageViews", fft_image and phot_image.
# Using the syntax below, these are views into the larger image.
# Changes/additions to the sub-images referenced by the views are automatically
# reflected in the original image.
fft_image = image[galsim.BoundsI(1, nx, 1, ny)]
phot_image = image[galsim.BoundsI(nx + 3, 2 * nx + 2, 1, ny)]
logger.debug(
' Read in training sample galaxy and PSF from file')
t2 = time.time()
# Draw the profile
final.draw(fft_image)
logger.debug(
' Drew fft image. Total drawn flux = %f. .flux = %f',
fft_image.array.sum(), final.getFlux())
t3 = time.time()
# Add Poisson noise
sky_level_pixel = sky_level * pixel_scale**2
fft_image.addNoise(
galsim.PoissonNoise(rng, sky_level=sky_level_pixel))
t4 = time.time()
# The next two lines are just to get the output from this demo script
# to match the output from the parsing of demo7.yaml.
rng = galsim.UniformDeviate(random_seed + k)
rng()
rng()
rng()
rng()
# Repeat for photon shooting image.
# Photon shooting automatically convolves by the pixel, so we've made sure not
# to include it in the profile!
final_nopix.drawShoot(phot_image,
max_extra_noise=sky_level_pixel / 100,
rng=rng)
t5 = time.time()
# For photon shooting, galaxy already has Poisson noise, so we want to make
# sure not to add that noise again! Thus, we just add sky noise, which
# is Poisson with the mean = sky_level_pixel
pd = galsim.PoissonDeviate(rng, mean=sky_level_pixel)
# DeviateNoise just adds the action of the given deviate to every pixel.
phot_image.addNoise(galsim.DeviateNoise(pd))
# For PoissonDeviate, the mean is not zero, so for a background-subtracted
# image, we need to subtract the mean back off when we are done.
phot_image -= sky_level_pixel
logger.debug(
' Added Poisson noise. Image fluxes are now %f and %f',
fft_image.array.sum(), phot_image.array.sum())
t6 = time.time()
# Store that into the list of all images
all_images += [image]
k = k + 1
logger.info(
'%d: %s * %s, flux = %.2e, hlr = %.2f, ellip = (%.2f,%.2f)',
k, gal_name, psf_name, flux, hlr, gal_shape.getE1(),
gal_shape.getE2())
logger.debug(' Times: %f, %f, %f, %f, %f', t2 - t1, t3 - t2,
t4 - t3, t5 - t4, t6 - t5)
psf_times[ipsf] += t6 - t1
psf_fft_times[ipsf] += t3 - t2
psf_phot_times[ipsf] += t5 - t4
gal_times[igal] += t6 - t1
gal_fft_times[igal] += t3 - t2
gal_phot_times[igal] += t5 - t4
setup_times += t2 - t1
fft_times += t3 - t2
phot_times += t5 - t4
noise_times += t4 - t3 + t6 - t5
logger.info('Done making images of galaxies')
logger.info('')
logger.info('Some timing statistics:')
logger.info(' Total time for setup steps = %f', setup_times)
logger.info(' Total time for regular fft drawing = %f', fft_times)
logger.info(' Total time for photon shooting = %f', phot_times)
logger.info(' Total time for adding noise = %f', noise_times)
logger.info('')
logger.info('Breakdown by PSF type:')
for ipsf in range(len(psfs)):
logger.info(' %s: Total time = %f (fft: %f, phot: %f)',
psf_names[ipsf], psf_times[ipsf], psf_fft_times[ipsf],
psf_phot_times[ipsf])
logger.info('')
logger.info('Breakdown by Galaxy type:')
for igal in range(len(gals)):
logger.info(' %s: Total time = %f (fft: %f, phot: %f)',
gal_names[igal], gal_times[igal], gal_fft_times[igal],
gal_phot_times[igal])
logger.info('')
# Now write the image to disk.
# With any write command, you can optionally compress the file using several compression
# schemes:
# 'gzip' uses gzip on the full output file.
# 'bzip2' uses bzip2 on the full output file.
# 'rice' uses rice compression on the image, leaving the fits headers readable.
# 'gzip_tile' uses gzip in tiles on the output image, leaving the fits headers readable.
# 'hcompress' uses hcompress on the image, but it is only valid for 2-d data, so it
# doesn't work for writeCube.
# 'plio' uses plio on the image, but it is only valid for positive integer data.
# Furthermore, the first three have standard filename extensions associated with them,
# so if you don't specify a compression, but the filename ends with '.gz', '.bz2' or '.fz',
# the corresponding compression will be selected automatically.
# In other words, the `compression='gzip'` specification is actually optional here:
galsim.fits.writeCube(all_images, file_name, compression='gzip')
logger.info('Wrote fft image to fits data cube %r', file_name)
def main(argv):
"""
Make a fits image cube using parameters from an input catalog
- The number of images in the cube matches the number of rows in the catalog.
- Each image size is computed automatically by GalSim based on the Nyquist size.
- Only galaxies. No stars.
- PSF is Moffat
- Each galaxy is bulge plus disk: deVaucouleurs + Exponential.
- A fraction of the disk flux is placed into point sources, which can model
knots of star formation.
- The catalog's columns are:
0 PSF beta (Moffat exponent)
1 PSF FWHM
2 PSF e1
3 PSF e2
4 PSF trunc
5 Disc half-light-radius
6 Disc e1
7 Disc e2
8 Bulge half-light-radius
9 Bulge e1
10 Bulge e2
11 Galaxy dx (the two components have same center)
12 Galaxy dy
- Applied shear is the same for each galaxy
- Noise is Poisson using a nominal sky value of 1.e6
"""
logging.basicConfig(format="%(message)s",
level=logging.INFO,
stream=sys.stdout)
logger = logging.getLogger("demo4")
# Define some parameters we'll use below and make directories if needed.
cat_file_name = os.path.join('input', 'galsim_default_input.asc')
if not os.path.isdir('output'):
os.mkdir('output')
multi_file_name = os.path.join('output', 'multi.fits')
random_seed = 8241573
sky_level = 1.e6 # ADU / arcsec^2
pixel_scale = 1.0 # arcsec / pixel (size units in input catalog are pixels)
gal_flux = 1.e6 # arbitrary choice, makes nice (not too) noisy images
gal_g1 = -0.009 #
gal_g2 = 0.011 #
# the fraction of flux in each component
# 40% is in the bulge, 60% in a disk. 70% of that disk light is placed
# into point sources distributed as a random walk
bulge_frac = 0.4
disk_frac = 0.6
knot_frac = 0.42
smooth_disk_frac = 0.18
# number of knots of star formation. To simulate a nice irregular (all the
# flux is in knots) we find ~100 is a minimum number needed, but we will
# just use 10 here to make the demo run fast.
n_knots = 10
xsize = 64 # pixels
ysize = 64 # pixels
logger.info('Starting demo script 4 using:')
logger.info(' - parameters taken from catalog %r', cat_file_name)
logger.info(' - Moffat PSF (parameters from catalog)')
logger.info(' - pixel scale = %.2f', pixel_scale)
logger.info(' - Bulge + Disc galaxies (parameters from catalog)')
logger.info(' - 100 Point sources, distributed as random walk')
logger.info(' - Applied gravitational shear = (%.3f,%.3f)', gal_g1,
gal_g2)
logger.info(' - Poisson noise (sky level = %.1e).', sky_level)
# Read in the input catalog
cat = galsim.Catalog(cat_file_name)
# save a list of the galaxy images in the "images" list variable:
images = []
for k in range(cat.nobjects):
# Initialize the (pseudo-)random number generator that we will be using below.
# Use a different random seed for each object to get different noise realizations.
# Using sequential random seeds here is safer than it sounds. We use Mersenne Twister
# random number generators that are designed to be used with this kind of seeding.
# However, to be extra safe, we actually initialize one random number generator with this
# seed, generate and throw away two random values with that, and then use the next value
# to seed a completely different Mersenne Twister RNG. The result is that successive
# RNGs created this way produce very independent random number streams.
rng = galsim.BaseDeviate(random_seed + k + 1)
# Take the Moffat beta from the first column (called 0) of the input catalog:
# Note: cat.get(k,col) returns a string. To get the value as a float, use either
# cat.getFloat(k,col) or float(cat.get(k,col))
beta = cat.getFloat(k, 0)
# A Moffat's size may be either scale_radius, fwhm, or half_light_radius.
# Here we use fwhm, taking from the catalog as well.
fwhm = cat.getFloat(k, 1)
# A Moffat profile may be truncated if desired
# The units for this are expected to be arcsec (or specifically -- whatever units
# you are using for all the size values as defined by the pixel_scale).
trunc = cat.getFloat(k, 4)
# Note: You may omit the flux, since the default is flux=1.
psf = galsim.Moffat(beta=beta, fwhm=fwhm, trunc=trunc)
# Take the (e1, e2) shape parameters from the catalog as well.
psf = psf.shear(e1=cat.getFloat(k, 2), e2=cat.getFloat(k, 3))
# Galaxy is a bulge + disk(+knots) with parameters taken from the catalog:
# put some fraction of the disk light into knots of star formation
disk_hlr = cat.getFloat(k, 5)
disk_e1 = cat.getFloat(k, 6)
disk_e2 = cat.getFloat(k, 7)
bulge_hlr = cat.getFloat(k, 8)
bulge_e1 = cat.getFloat(k, 9)
bulge_e2 = cat.getFloat(k, 10)
smooth_disk = galsim.Exponential(flux=smooth_disk_frac,
half_light_radius=disk_hlr)
knots = galsim.RandomKnots(n_knots,
half_light_radius=disk_hlr,
flux=knot_frac,
rng=rng)
disk = galsim.Add([smooth_disk, knots])
disk = disk.shear(e1=disk_e1, e2=disk_e2)
# the rest of the light goes into the bulge
bulge = galsim.DeVaucouleurs(flux=bulge_frac,
half_light_radius=bulge_hlr)
bulge = bulge.shear(e1=bulge_e1, e2=bulge_e2)
# The flux of an Add object is the sum of the component fluxes.
# Note that in demo3.py, a similar addition was performed by the binary operator "+".
gal = galsim.Add([disk, bulge])
# This flux may be overridden by withFlux. The relative fluxes of the components
# remains the same, but the total flux is set to gal_flux.
gal = gal.withFlux(gal_flux)
gal = gal.shear(g1=gal_g1, g2=gal_g2)
# The center of the object is normally placed at the center of the postage stamp image.
# You can change that with shift:
gal = gal.shift(dx=cat.getFloat(k, 11), dy=cat.getFloat(k, 12))
final = galsim.Convolve([psf, gal])
# Draw the profile
image = galsim.ImageF(xsize, ysize)
final.drawImage(image, scale=pixel_scale)
# Add Poisson noise to the image:
image.addNoise(galsim.PoissonNoise(rng, sky_level * pixel_scale**2))
logger.info('Drew image for object at row %d in the input catalog' % k)
# Add the image to our list of images
images.append(image)
# Now write the images to a multi-extension fits file. Each image will be in its own HDU.
galsim.fits.writeMulti(images, multi_file_name)
logger.info('Images written to multi-extension fits file %r',
multi_file_name)
def test_hsmparams_nodefault():
"""Test that when non-default hsmparams are used, the results change."""
import time
# First make some profile
bulge = galsim.DeVaucouleurs(half_light_radius=0.3)
disk = galsim.Exponential(half_light_radius=0.5)
disk = disk.shear(e1=0.2, e2=-0.3)
psf = galsim.Kolmogorov(fwhm=0.6)
gal = bulge + disk # equal weighting, i.e., B/T=0.5
tot_gal = galsim.Convolve(gal, psf)
tot_gal_image = tot_gal.drawImage(scale=0.18)
tot_psf_image = psf.drawImage(scale=0.18)
# Check that recompute_flux changes give results that are as expected
test_t = time.time()
res = galsim.hsm.EstimateShear(tot_gal_image, tot_psf_image)
dt = time.time() - test_t
res2 = galsim.hsm.EstimateShear(tot_gal_image,
tot_psf_image,
recompute_flux='sum')
assert (res.moments_amp <
res2.moments_amp), 'Incorrect behavior with recompute_flux=sum'
res3 = galsim.hsm.EstimateShear(tot_gal_image,
tot_psf_image,
recompute_flux='none')
assert (
res3.moments_amp == 0), 'Incorrect behavior with recompute_flux=none'
# Check that results, timing change as expected with nsig_rg
# For this, use Gaussian as galaxy and for ePSF, i.e., no extra pixel response
p = galsim.Gaussian(fwhm=10.)
g = galsim.Gaussian(fwhm=20.)
g = g.shear(g1=0.5)
obj = galsim.Convolve(g, p)
# HSM allows a slop of 1.e-8 on nsig_rg, which means that default float32 images don't
# actually end up with different result when using nsig_rg=0. rather than 3.
im = obj.drawImage(scale=1., method='no_pixel', dtype=float)
psf_im = p.drawImage(scale=1., method='no_pixel', dtype=float)
test_t1 = time.time()
g_res = galsim.hsm.EstimateShear(im, psf_im)
test_t2 = time.time()
g_res2 = galsim.hsm.EstimateShear(
im, psf_im, hsmparams=galsim.hsm.HSMParams(nsig_rg=0.))
dt2 = time.time() - test_t2
dt1 = test_t2 - test_t1
if test_timing:
assert (
dt2 > dt1
), 'Should take longer to estimate shear without truncation of galaxy'
assert (not equal_hsmshapedata(
g_res, g_res2)), 'Results should differ with diff nsig_rg'
assert g_res != g_res2, 'Results should differ with diff nsig_rg'
# Check that results, timing change as expected with max_moment_nsig2
test_t2 = time.time()
res2 = galsim.hsm.EstimateShear(
tot_gal_image,
tot_psf_image,
hsmparams=galsim.hsm.HSMParams(max_moment_nsig2=9.))
dt2 = time.time() - test_t2
if test_timing:
assert (
dt2 < dt
), 'Should be faster to estimate shear with lower max_moment_nsig2'
assert (not equal_hsmshapedata(
res, res2)), 'Outputs same despite change in max_moment_nsig2'
assert res != res2, 'Outputs same despite change in max_moment_nsig2'
assert (res.moments_sigma >
res2.moments_sigma), 'Sizes do not change as expected'
assert (res.moments_amp >
res2.moments_amp), 'Amplitudes do not change as expected'
# Check that max_amoment, max_ashift work as expected
try:
np.testing.assert_raises(
RuntimeError,
galsim.hsm.EstimateShear,
tot_gal_image,
tot_psf_image,
hsmparams=galsim.hsm.HSMParams(max_amoment=10.))
np.testing.assert_raises(
RuntimeError,
galsim.hsm.EstimateShear,
tot_gal_image,
tot_psf_image,
guess_centroid=galsim.PositionD(47.,
tot_gal_image.trueCenter().y),
hsmparams=galsim.hsm.HSMParams(max_ashift=0.1))
except ImportError:
print('The assert_raises tests require nose')
def test_hsmparams():
"""Test the ability to set/change parameters that define how moments/shape estimation are done."""
# First make some profile, and make sure that we get the same answers when we specify default
# hsmparams or don't specify hsmparams at all.
default_hsmparams = galsim.hsm.HSMParams(nsig_rg=3.0,
nsig_rg2=3.6,
max_moment_nsig2=25.0,
regauss_too_small=1,
adapt_order=2,
convergence_threshold=1.e-6,
max_mom2_iter=400,
num_iter_default=-1,
bound_correct_wt=0.25,
max_amoment=8000.,
max_ashift=15.,
ksb_moments_max=4,
failed_moments=-1000.)
bulge = galsim.DeVaucouleurs(half_light_radius=0.3)
disk = galsim.Exponential(half_light_radius=0.5)
disk = disk.shear(e1=0.2, e2=-0.3)
psf = galsim.Kolmogorov(fwhm=0.6)
gal = bulge + disk # equal weighting, i.e., B/T=0.5
tot_gal = galsim.Convolve(gal, psf)
tot_gal_image = tot_gal.drawImage(scale=0.18)
tot_psf_image = psf.drawImage(scale=0.18)
res = tot_gal_image.FindAdaptiveMom()
res_def = tot_gal_image.FindAdaptiveMom(hsmparams=default_hsmparams)
assert (equal_hsmshapedata(
res, res_def)), 'Moment outputs differ when using default HSMParams'
assert res == res_def, 'Moment outputs differ when using default HSMParams'
res2 = galsim.hsm.EstimateShear(tot_gal_image, tot_psf_image)
res2_def = galsim.hsm.EstimateShear(tot_gal_image,
tot_psf_image,
hsmparams=default_hsmparams)
assert (equal_hsmshapedata(
res, res_def)), 'Shear outputs differ when using default HSMParams'
assert res == res_def, 'Shear outputs differ when using default HSMParams'
do_pickle(default_hsmparams)
do_pickle(
galsim.hsm.HSMParams(nsig_rg=1.0,
nsig_rg2=1.6,
max_moment_nsig2=2.0,
regauss_too_small=0,
adapt_order=0,
convergence_threshold=1.e-8,
max_mom2_iter=100,
num_iter_default=4,
bound_correct_wt=0.05,
max_amoment=80.,
max_ashift=5.,
ksb_moments_max=2,
failed_moments=99.))
do_pickle(res)
do_pickle(res2)
do_pickle(galsim._galsim.CppShapeData())
try:
# Then check failure modes: force it to fail by changing HSMParams.
new_params_niter = galsim.hsm.HSMParams(
max_mom2_iter=res.moments_n_iter - 1)
new_params_size = galsim.hsm.HSMParams(max_amoment=0.3 *
res.moments_sigma**2)
np.testing.assert_raises(RuntimeError,
galsim.hsm.FindAdaptiveMom,
tot_gal_image,
hsmparams=new_params_niter)
np.testing.assert_raises(RuntimeError,
galsim.hsm.EstimateShear,
tot_gal_image,
tot_psf_image,
hsmparams=new_params_size)
except ImportError:
print('The assert_raises tests require nose')
def main(argv):
"""
Make a fits image cube where each frame has two images of the same galaxy drawn
with regular FFT convolution and with photon shooting.
We do this for 5 different PSFs and 5 different galaxies, each with 4 different (random)
fluxes, sizes, and shapes.
"""
logging.basicConfig(format="%(message)s",
level=logging.INFO,
stream=sys.stdout)
logger = logging.getLogger("demo7")
# To turn off logging:
#logger.propagate = False
# To turn on the debugging messages:
#logger.setLevel(logging.DEBUG)
# Define some parameters we'll use below.
# Make output directory if not already present.
if not os.path.isdir('output'):
os.mkdir('output')
file_name = os.path.join('output', 'cube_phot.fits.gz')
random_seed = 553728
sky_level = 1.e4 # ADU / arcsec^2
pixel_scale = 0.28 # arcsec
nx = 64
ny = 64
gal_flux_min = 1.e4 # Range for galaxy flux
gal_flux_max = 1.e5
gal_hlr_min = 0.3 # arcsec
gal_hlr_max = 1.3 # arcsec
gal_e_min = 0. # Range for ellipticity
gal_e_max = 0.8
psf_fwhm = 0.65 # arcsec
# This script is set up as a comparison between using FFTs for doing the convolutions and
# shooting photons. The two methods have trade-offs in speed and accuracy which vary
# with the kind of profile being drawn and the S/N of the object, among other factors.
# In addition, for each method, there are a number of parameters GalSim uses that control
# aspects of the calculation that further affect the speed and accuracy.
#
# We encapsulate these parameters with an object called GSParams. The default values
# are intended to be accurate enough for normal precision shear tests, without sacrificing
# too much speed.
#
# Any PSF or galaxy object can be given a gsparams argument on construction that can
# have different values to make the calculation more or less accurate (typically trading
# off for speed or memory).
#
# In this script, we adjust some of the values slightly, just to show you how it works.
# You could play around with these values and see what effect they have on the drawn images.
# Usually, it requires a pretty drastic change in these parameters for you to be able to
# notice the difference by eye. But subtle effects that may impact the shapes of galaxies
# can happen well before then.
# Type help(galsim.GSParams) for the complete list of parameters and more detailed
# documentation, including the default values for each parameter.
gsparams = galsim.GSParams(
folding_threshold=
1.e-2, # maximum fractional flux that may be folded around edge of FFT
maxk_threshold=
2.e-3, # k-values less than this may be excluded off edge of FFT
xvalue_accuracy=
1.e-4, # approximations in real space aim to be this accurate
kvalue_accuracy=
1.e-4, # approximations in fourier space aim to be this accurate
shoot_accuracy=
1.e-4, # approximations in photon shooting aim to be this accurate
minimum_fft_size=64) # minimum size of ffts
logger.info('Starting demo script 7')
# Make the PSF profiles:
psf1 = galsim.Gaussian(fwhm=psf_fwhm, gsparams=gsparams)
psf2 = galsim.Moffat(fwhm=psf_fwhm, beta=2.4, gsparams=gsparams)
psf3_inner = galsim.Gaussian(fwhm=psf_fwhm, flux=0.8, gsparams=gsparams)
psf3_outer = galsim.Gaussian(fwhm=2 * psf_fwhm,
flux=0.2,
gsparams=gsparams)
psf3 = psf3_inner + psf3_outer
atmos = galsim.Gaussian(fwhm=psf_fwhm, gsparams=gsparams)
# The OpticalPSF and set of Zernike values chosen below correspond to a reasonably well aligned,
# smallish ~0.3m / 12 inch diameter telescope with a central obscuration of ~0.12m or 5 inches
# diameter, being used in optical wavebands.
# In the Noll convention, the value of the Zernike coefficient also gives the RMS optical path
# difference across a circular pupil. An RMS difference of ~0.5 or larger indicates that parts
# of the wavefront are in fully destructive interference, and so we might expect aberrations to
# become strong when Zernike aberrations summed in quadrature approach 0.5 wave.
# The aberrations chosen in this case correspond to operating close to a 0.25 wave RMS optical
# path difference. Unlike in demo3, we specify the aberrations by making a list that we pass
# in using the 'aberrations' kwarg. The order of aberrations starting from index 4 is defocus,
# astig1, astig2, coma1, coma2, trefoil1, trefoil2, spher as in the Noll convention.
# We ignore the first 4 values so that the index number corresponds to the Zernike index
# in the Noll convention. This will be particularly convenient once we start allowing
# coefficients beyond spherical (index 11). c.f. The Wikipedia page about the Noll indices:
#
# http://en.wikipedia.org/wiki/Zernike_polynomials#Zernike_polynomials
aberrations = [0.0] * 12 # Set the initial size.
aberrations[4] = 0.06 # Noll index 4 = Defocus
aberrations[5:7] = [0.12, -0.08] # Noll index 5,6 = Astigmatism
aberrations[7:9] = [0.07, 0.04] # Noll index 7,8 = Coma
aberrations[11] = -0.13 # Noll index 11 = Spherical
# You could also define these all at once if that is more convenient:
#aberrations = [0.0, 0.0, 0.0, 0.0, 0.06, 0.12, -0.08, 0.07, 0.04, 0.0, 0.0, -0.13]
optics = galsim.OpticalPSF(lam_over_diam=0.6 * psf_fwhm,
obscuration=0.4,
aberrations=aberrations,
gsparams=gsparams)
psf4 = galsim.Convolve([atmos, optics
]) # Convolve inherits the gsparams from the first
# item in the list. (Or you can supply a gsparams
# argument explicitly if you want to override this.)
atmos = galsim.Kolmogorov(fwhm=psf_fwhm, gsparams=gsparams)
optics = galsim.Airy(lam_over_diam=0.3 * psf_fwhm, gsparams=gsparams)
psf5 = galsim.Convolve([atmos, optics])
psfs = [psf1, psf2, psf3, psf4, psf5]
psf_names = [
"Gaussian", "Moffat", "Double Gaussian", "OpticalPSF",
"Kolmogorov * Airy"
]
psf_times = [0, 0, 0, 0, 0]
psf_fft_times = [0, 0, 0, 0, 0]
psf_phot_times = [0, 0, 0, 0, 0]
# Make the galaxy profiles:
gal1 = galsim.Gaussian(half_light_radius=1, gsparams=gsparams)
gal2 = galsim.Exponential(half_light_radius=1, gsparams=gsparams)
gal3 = galsim.DeVaucouleurs(half_light_radius=1, gsparams=gsparams)
gal4 = galsim.Sersic(half_light_radius=1, n=2.5, gsparams=gsparams)
# A Sersic profile may be truncated if desired.
# The units for this are expected to be arcsec (or specifically -- whatever units
# you are using for all the size values as defined by the pixel_scale).
bulge = galsim.Sersic(half_light_radius=0.7,
n=3.2,
trunc=8.5,
gsparams=gsparams)
disk = galsim.Sersic(half_light_radius=1.2, n=1.5, gsparams=gsparams)
gal5 = 0.4 * bulge + 0.6 * disk # Net half-light radius is only approximate for this one.
gals = [gal1, gal2, gal3, gal4, gal5]
gal_names = [
"Gaussian", "Exponential", "Devaucouleurs", "n=2.5 Sersic",
"Bulge + Disk"
]
gal_times = [0, 0, 0, 0, 0]
gal_fft_times = [0, 0, 0, 0, 0]
gal_phot_times = [0, 0, 0, 0, 0]
# Other times to keep track of:
setup_times = 0
fft_times = 0
phot_times = 0
noise_times = 0
# Loop over combinations of psf, gal, and make 4 random choices for flux, size, shape.
all_images = []
k = 0
for ipsf in range(len(psfs)):
psf = psfs[ipsf]
psf_name = psf_names[ipsf]
logger.info('psf %d: %s', ipsf + 1, psf)
# Note that this implicitly calls str(psf). We've made an effort to give all GalSim
# objects an informative but relatively succinct str representation. Some details may
# be missing, but it should look essentially like how you would create the object.
logger.debug('repr = %r', psf)
# The repr() version are a bit more pedantic in form and should be completely informative,
# to the point where two objects that are not identical should never have equal repr
# strings. As such the repr strings may in some cases be somewhat unwieldy. For instance,
# since we set non-default gsparams in these, the repr includes that information, but
# it is omitted from the str for brevity.
for igal in range(len(gals)):
gal = gals[igal]
gal_name = gal_names[igal]
logger.info(' galaxy %d: %s', igal + 1, gal)
logger.debug(' repr = %r', gal)
for i in range(4):
logger.debug(' Start work on image %d', i)
t1 = time.time()
# Initialize the random number generator we will be using.
rng = galsim.UniformDeviate(random_seed + k)
# Generate random variates:
flux = rng() * (gal_flux_max - gal_flux_min) + gal_flux_min
# Use a new variable name, since we'll want to keep the original unmodified.
this_gal = gal.withFlux(flux)
hlr = rng() * (gal_hlr_max - gal_hlr_min) + gal_hlr_min
this_gal = this_gal.dilate(hlr)
beta_ellip = rng() * 2 * math.pi * galsim.radians
ellip = rng() * (gal_e_max - gal_e_min) + gal_e_min
gal_shape = galsim.Shear(e=ellip, beta=beta_ellip)
this_gal = this_gal.shear(gal_shape)
# Build the final object by convolving the galaxy and PSF.
final = galsim.Convolve([this_gal, psf])
# Create the large, double width output image
# Rather than provide a scale= argument to the drawImage commands, we can also
# set the pixel scale in the image constructor.
# Note: You can also change it after the construction with im.scale=pixel_scale
image = galsim.ImageF(2 * nx + 2, ny, scale=pixel_scale)
# Assign the following two Image "views", fft_image and phot_image.
# Using the syntax below, these are views into the larger image.
# Changes/additions to the sub-images referenced by the views are automatically
# reflected in the original image.
fft_image = image[galsim.BoundsI(1, nx, 1, ny)]
phot_image = image[galsim.BoundsI(nx + 3, 2 * nx + 2, 1, ny)]
logger.debug(
' Read in training sample galaxy and PSF from file')
t2 = time.time()
# Draw the profile
# This default rendering method (method='auto') usually defaults to FFT, since
# that is normally the most efficient method. However, we can also set method
# to 'fft' explicitly to force it to always use FFTs for the convolution
# by the pixel response. (In this case, it doesn't have any effect, since
# the 'auto' method would have always chosen 'fft' anyway, so this is just
# for illustrative purposes.)
final.drawImage(fft_image, method='fft')
logger.debug(
' Drew fft image. Total drawn flux = %f. .flux = %f',
fft_image.array.sum(), final.getFlux())
t3 = time.time()
# Add Poisson noise
sky_level_pixel = sky_level * pixel_scale**2
fft_image.addNoise(
galsim.PoissonNoise(rng, sky_level=sky_level_pixel))
t4 = time.time()
# The next two lines are just to get the output from this demo script
# to match the output from the parsing of demo7.yaml.
rng = galsim.UniformDeviate(random_seed + k)
rng()
rng()
rng()
rng()
# Repeat for photon shooting image.
# The max_extra_noise parameter indicates how much extra noise per pixel we are
# willing to tolerate. The sky noise will be adding a variance of sky_level_pixel,
# so we allow up to 1% of that extra.
final.drawImage(phot_image,
method='phot',
max_extra_noise=sky_level_pixel / 100,
rng=rng)
t5 = time.time()
# For photon shooting, galaxy already has Poisson noise, so we want to make
# sure not to add that noise again! Thus, we just add sky noise, which
# is Poisson with the mean = sky_level_pixel
pd = galsim.PoissonDeviate(rng, mean=sky_level_pixel)
# DeviateNoise just adds the action of the given deviate to every pixel.
phot_image.addNoise(galsim.DeviateNoise(pd))
# For PoissonDeviate, the mean is not zero, so for a background-subtracted
# image, we need to subtract the mean back off when we are done.
phot_image -= sky_level_pixel
logger.debug(
' Added Poisson noise. Image fluxes are now %f and %f',
fft_image.array.sum(), phot_image.array.sum())
t6 = time.time()
# Store that into the list of all images
all_images += [image]
k = k + 1
logger.info(
' %d: flux = %.2e, hlr = %.2f, ellip = (%.2f,%.2f)',
k, flux, hlr, gal_shape.getE1(), gal_shape.getE2())
logger.debug(' Times: %f, %f, %f, %f, %f', t2 - t1,
t3 - t2, t4 - t3, t5 - t4, t6 - t5)
psf_times[ipsf] += t6 - t1
psf_fft_times[ipsf] += t3 - t2
psf_phot_times[ipsf] += t5 - t4
gal_times[igal] += t6 - t1
gal_fft_times[igal] += t3 - t2
gal_phot_times[igal] += t5 - t4
setup_times += t2 - t1
fft_times += t3 - t2
phot_times += t5 - t4
noise_times += t4 - t3 + t6 - t5
logger.info('Done making images of galaxies')
logger.info('')
logger.info('Some timing statistics:')
logger.info(' Total time for setup steps = %f', setup_times)
logger.info(' Total time for regular fft drawing = %f', fft_times)
logger.info(' Total time for photon shooting = %f', phot_times)
logger.info(' Total time for adding noise = %f', noise_times)
logger.info('')
logger.info('Breakdown by PSF type:')
for ipsf in range(len(psfs)):
logger.info(' %s: Total time = %f (fft: %f, phot: %f)',
psf_names[ipsf], psf_times[ipsf], psf_fft_times[ipsf],
psf_phot_times[ipsf])
logger.info('')
logger.info('Breakdown by Galaxy type:')
for igal in range(len(gals)):
logger.info(' %s: Total time = %f (fft: %f, phot: %f)',
gal_names[igal], gal_times[igal], gal_fft_times[igal],
gal_phot_times[igal])
logger.info('')
# Now write the image to disk.
# With any write command, you can optionally compress the file using several compression
# schemes:
# 'gzip' uses gzip on the full output file.
# 'bzip2' uses bzip2 on the full output file.
# 'rice' uses rice compression on the image, leaving the fits headers readable.
# 'gzip_tile' uses gzip in tiles on the output image, leaving the fits headers readable.
# 'hcompress' uses hcompress on the image, but it is only valid for 2-d data, so it
# doesn't work for writeCube.
# 'plio' uses plio on the image, but it is only valid for positive integer data.
# Furthermore, the first three have standard filename extensions associated with them,
# so if you don't specify a compression, but the filename ends with '.gz', '.bz2' or '.fz',
# the corresponding compression will be selected automatically.
# In other words, the `compression='gzip'` specification is actually optional here:
galsim.fits.writeCube(all_images, file_name, compression='gzip')
logger.info('Wrote fft image to fits data cube %r', file_name)
def galSimFakeSersic(flux, gal, psfImage=None, scaleRad=False, returnObj=True,
expAll=False, devAll=False, plotFake=False, trunc=0,
drawMethod="no_pixel", addPoisson=False, scale=1.0,
transform=None, addShear=False):
"""
Make a fake single Sersic galaxy using the galSim.Sersic function
Inputs: total flux of the galaxy, and a record array that stores the
necessary parameters [reffPix, nSersic, axisRatio, posAng]
Output: a 2-D image array of the galaxy model OR
a GalSim object of the model
Options:
psfImage: PSF image for convolution
trunc: Flux of Sersic models will truncate at trunc * reffPix
radius; trunc=0 means no truncation
drawMethod: The method for drawImage: ['auto', 'fft', 'real_space']
addPoisson: Add Poisson noise
plotFake: Generate a PNG figure of the model
expAll: Input model will be seen as nSersic=1
devAll: Input model will be seen as nSersic=4
returnObj: If TRUE, will return the GSObj
"""
reff = float(gal["reff"])
posAng = float(gal["theta"])
axisRatio = float(gal["b_a"])
nSersic = float(gal["sersic_n"])
# Truncate the flux at trunc x reff
if trunc > 0:
trunc = trunc * reff
# Make sure Sersic index is not too large
if nSersic > 6.0:
raise ValueError("Sersic index is too large! Should be <= 6.0")
# Check the axisRatio value
if axisRatio <= 0.05:
raise ValueError("Axis Ratio is too small! Should be >= 0.05")
# Make the Sersic model based on flux, re, and Sersic index
if nSersic == 1.0 or expAll:
if scaleRad:
serObj = galsim.Exponential(scale_radius=reff)
else:
serObj = galsim.Exponential(half_light_radius=reff)
if expAll:
print " * Treated as a n=1 Exponential disk : %d" % (gal["ID"])
elif nSersic == 4.0 or devAll:
serObj = galsim.DeVaucouleurs(half_light_radius=reff, trunc=trunc)
if devAll:
print " * Treated as a n=4 De Vaucouleurs model: %d" % (gal["ID"])
elif nSersic <= 0.9:
serObj = galsim.Sersic(nSersic, half_light_radius=reff)
else:
serObj = galsim.Sersic(nSersic, half_light_radius=reff,
trunc=trunc)
# If necessary, apply the Axis Ratio (q=b/a) using the Shear method
if axisRatio < 1.0:
serObj = serObj.shear(q=axisRatio, beta=(0.0 * galsim.degrees))
# If necessary, apply the Position Angle (theta) using the Rotate method
# if posAng != 0.0 or posAng != 180.0:
serObj = serObj.rotate((90.0 - posAng) * galsim.degrees)
# If necessary, apply addtion shear (e.g. for weak lensing test)
if addShear:
try:
g1 = float(gal['g1'])
g2 = float(gal['g2'])
serObj = serObj.shear(g1=g1, g2=g2)
except ValueError:
warnings.warn("Can not find g1 or g2 in the input!\n",
" No shear has been added!")
# Do the transformation from sky to pixel coordinates, if given
if transform is not None:
serObj = serObj.transform(*tuple(transform.ravel()))
# Pass the flux to the object
serObj = serObj.withFlux(float(flux))
# Convolve the Sersic model using the provided PSF image
if psfImage is not None:
# Convert the PSF Image Array into a GalSim Object
# Norm=True by default
psfObj = arrayToGSObj(psfImage, norm=True)
serFinal = galsim.Convolve([serObj, psfObj])
else:
serFinal = serObj
# Make a PNG figure of the fake galaxy to check if everything is Ok
if plotFake:
plotFakeGalaxy(serFinal, galID=gal['ID'])
# Now, by default, the function will just return the GSObj
if returnObj:
return serFinal
else:
return galSimDrawImage(serFinal, method=drawMethod, scale=scale,
addPoisson=addPoisson)
def _get_models(self):
"""
get models for each band
"""
import galsim
rng = self.rng
o = self['objects']
shift = self._get_shift()
fracdev = rng.uniform(
low=o['fracdev_range'][0],
high=o['fracdev_range'][1],
)
disk_hlr = rng.uniform(
low=o['hlr_range'][0],
high=o['hlr_range'][1],
)
bulge_sizefrac = rng.uniform(
low=o['bulge_sizefrac_range'][0],
high=o['bulge_sizefrac_range'][1],
)
bulge_hlr = disk_hlr * bulge_sizefrac
if o['flux_range'] == 'track_hlr':
flux = disk_hlr**2 * 100
else:
flux = rng.uniform(
low=o['flux_range'][0],
high=o['flux_range'][1],
)
g1disk, g2disk = self.gpdf.sample2d()
bulge_angle_offset = rng.uniform(
low=o['bulge_angle_offet_range'][0],
high=o['bulge_angle_offet_range'][1],
)
bulge_angle_offset = np.deg2rad(bulge_angle_offset)
disk_shape = ngmix.Shape(g1disk, g2disk)
bulge_shape = disk_shape.get_rotated(bulge_angle_offset)
disk = galsim.Exponential(
half_light_radius=disk_hlr,
flux=(1 - fracdev) * flux,
).shear(
g1=disk_shape.g1,
g2=disk_shape.g2,
).shift(*shift, )
bulge = galsim.DeVaucouleurs(
half_light_radius=bulge_hlr,
flux=fracdev * flux,
).shear(
g1=bulge_shape.g1,
g2=bulge_shape.g2,
).shift(*shift, )
disk_color = o['disk_color']
bulge_color = o['bulge_color']
gdisk = disk * disk_color[0]
rdisk = disk * disk_color[1]
idisk = disk * disk_color[2]
gbulge = bulge * bulge_color[0]
rbulge = bulge * bulge_color[1]
ibulge = bulge * bulge_color[2]
gmodel = galsim.Add(gdisk, gbulge)
rmodel = galsim.Add(rdisk, rbulge)
imodel = galsim.Add(idisk, ibulge)
obj_data = self._get_obj_data_struct()
obj_data['shift'] = shift
obj_data['flux'] = flux
obj_data['hlr'] = disk_hlr
return (gmodel, rmodel, imodel), obj_data