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fiberloss method is updated for dithering simulations #103

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fiberloss method is updated for dithering simulations
tolgayapici Apr 8, 2019
2a45d71
[skip ci] we move psfs rather than the aperture
tolgayapici Nov 12, 2019
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39 changes: 28 additions & 11 deletions specsim/fiberloss.py
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Original file line number Diff line number Diff line change
Expand Up @@ -32,13 +32,17 @@ class GalsimFiberlossCalculator(object):
moffat_beta : float
Beta parameter value for the atmospheric PSF Moffat profile.
maximum_fft_size : int
Maximum size of FFT allowed.
5~ Maximum size of FFT allowed.
fiber_placement : array
Fiber placement position in microns. It is needed for dithering simulations.
"""
def __init__(self, fiber_diameter, wlen_grid, num_pixels=16,
oversampling=32, moffat_beta=3.5, maximum_fft_size=32767):
oversampling=32, moffat_beta=3.5, maximum_fft_size=32767,
fiber_placement=[0., 0.]):

self.wlen_grid = np.asarray(wlen_grid)
self.moffat_beta = moffat_beta
self.fiber_placement = fiber_placement

# Defer import to runtime.
import galsim
Expand All @@ -48,21 +52,20 @@ def __init__(self, fiber_diameter, wlen_grid, num_pixels=16,
# rather than on-sky angles.
scale = fiber_diameter / num_pixels
self.image = galsim.Image(num_pixels, num_pixels, scale=scale)

self.gsparams = galsim.GSParams(maximum_fft_size=32767)

# Prepare an anti-aliased image of the fiber aperture.
nos = num_pixels * oversampling
dxy = (np.arange(nos) + 0.5 - 0.5 * nos) / (0.5 * nos)
rsq = dxy ** 2 + dxy[:, np.newaxis] ** 2
dx = (np.arange(nos) + 0.5 - 0.5 * nos) / (0.5 * nos)# - self.fiber_placement[0]/0.5/fiber_diameter
dy = (np.arange(nos) + 0.5 - 0.5 * nos) / (0.5 * nos)# - self.fiber_placement[1]/0.5/fiber_diameter
rsq = dx ** 2 + dy[:, np.newaxis] ** 2
inside = (rsq <= 1).astype(float)
s0, s1 = inside.strides
blocks = numpy.lib.stride_tricks.as_strided(
inside, shape=(num_pixels, num_pixels, oversampling, oversampling),
strides=(oversampling * s0, oversampling * s1, s0, s1))
self.aperture = blocks.sum(axis=(2, 3)) / oversampling ** 2



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.
Expand Down Expand Up @@ -123,7 +126,7 @@ def create_source(self, fractions, half_light_radius,
def calculate(self, seeing_fwhm, scale, offset, blur_rms,
source_fraction, source_half_light_radius,
source_minor_major_axis_ratio, source_position_angle,
saved_images_file=None):
saved_images_file=None, verbosity=False):
"""Calculate the acceptance fractions for a set of fibers.

Parameters
Expand Down Expand Up @@ -214,8 +217,12 @@ def calculate(self, seeing_fwhm, scale, offset, blur_rms,
# this fiber location.
atmospheric_psf = seeing.transform(
scale[j, 0], 0, 0, scale[j, 1]).withFlux(1)
if verbosity:
print("Atmoshperic PSF: ", atmospheric_psf)
# Create the instrument PSF for this fiber and wavelength.
instrument_psf = galsim.Gaussian(sigma=blur_rms[j, i])
if verbosity:
print("Instrument PSF: ", instrument_psf)
if i == 0:
# Create the source profile for this fiber on the sky.
source_profile = self.create_source(
Expand All @@ -229,6 +236,8 @@ def calculate(self, seeing_fwhm, scale, offset, blur_rms,
else:
# Lookup the source model for this fiber.
source_profile = source_profiles[j]
if verbosity:
print("Source profile: ", source_profile)
# Convolve the source + instrument + astmosphere.
convolved = galsim.Convolve(
[instrument_psf, atmospheric_psf, source_profile],
Expand All @@ -238,10 +247,14 @@ def calculate(self, seeing_fwhm, scale, offset, blur_rms,
# TODO: compare method='no_pixel' and 'auto' for
# accuracy and speed.
draw_args = dict(image=self.image, method='auto')
if verbosity:
print("Draw args: ", draw_args)
print("Offsets: ", offsets)
print("GS params: ", self.gsparams)
convolved.drawImage(offset=offsets, **draw_args)
# Calculate the fiberloss fraction for this fiber and wlen.
fiberloss[j, i] = np.sum(self.image.array * self.aperture)

if saved_images_file is not None:
header['FIBER'] = j
header['WLEN'] = wlen
Expand Down Expand Up @@ -280,7 +293,8 @@ def calculate_fiber_acceptance_fraction(
focal_x, focal_y, wavelength, source, atmosphere, instrument,
source_types=None, source_fraction=None, source_half_light_radius=None,
source_minor_major_axis_ratio=None, source_position_angle=None,
oversampling=32, saved_images_file=None, saved_table_file=None):
oversampling=32, saved_images_file=None, saved_table_file=None,
fiber_placement=[0., 0.]):
"""Calculate the acceptance fraction for a single fiber.

The behavior of this function is customized by the instrument.fiberloss
Expand Down Expand Up @@ -345,6 +359,8 @@ def calculate_fiber_acceptance_fraction(
extension determines the file format, and .ecsv is recommended.
The saved file can then be used as a pre-tabulated input with
instrument.fiberloss.method = 'table'.
fiber_placement : array
Fiber placement position in microns. It is needed for the dithering simulations.

Returns
-------
Expand Down Expand Up @@ -464,7 +480,8 @@ def calculate_fiber_acceptance_fraction(
# with implicit units.
fiberloss_grid = calc.calculate(
seeing_fwhm,
scale.to(u.um / u.arcsec).value, offset.to(u.um).value,
scale.to(u.um / u.arcsec).value,
offset.to(u.um).value + fiber_placement,
blur.to(u.um).value,
source_fraction, source_half_light_radius,
source_minor_major_axis_ratio, source_position_angle,
Expand Down