def test__from_main_plane_redshifts_and_slices(self):
ordered_plane_redshifts = ordered_plane_redshifts_with_slicing_from(
lens_redshifts=[1.0],
source_plane_redshift=3.0,
planes_between_lenses=[1, 1],
)
assert ordered_plane_redshifts == [0.5, 1.0, 2.0]
def test__different_number_of_slices_between_planes(self):
ordered_plane_redshifts = ordered_plane_redshifts_with_slicing_from(
lens_redshifts=[1.0],
source_plane_redshift=2.0,
planes_between_lenses=[2, 3],
)
assert ordered_plane_redshifts == [
(1.0 / 3.0),
(2.0 / 3.0),
1.0,
1.25,
1.5,
1.75,
]
def test__if_number_of_input_slices_is_not_equal_to_number_of_plane_intervals__raises_errror(
self, ):
with pytest.raises(exc.PlaneException):
ordered_plane_redshifts_with_slicing_from(
lens_redshifts=[1.0],
source_plane_redshift=2.0,
planes_between_lenses=[2, 3, 1],
)
with pytest.raises(exc.PlaneException):
ordered_plane_redshifts_with_slicing_from(
lens_redshifts=[1.0],
source_plane_redshift=2.0,
planes_between_lenses=[2],
)
with pytest.raises(exc.PlaneException):
ordered_plane_redshifts_with_slicing_from(
lens_redshifts=[1.0, 3.0],
source_plane_redshift=2.0,
planes_between_lenses=[2],
)
def sliced_tracer_from_lens_line_of_sight_and_source_galaxies(
cls,
lens_galaxies,
line_of_sight_galaxies,
source_galaxies,
planes_between_lenses,
cosmology=cosmo.Planck15,
):
"""Ray-tracer for a lens system with any number of planes.
The redshift of these planes are specified by the input parameters *lens_redshifts* and \
*slices_between_main_planes*. Every galaxy is placed in its closest plane in redshift-space.
To perform multi-plane ray-tracing, a cosmology must be supplied so that deflection-angles can be rescaled \
according to the lens-geometry of the multi-plane system. All galaxies input to the tracer must therefore \
have redshifts.
This tracer has only one grid (see gridStack) which is used for ray-tracing.
Parameters
----------
lens_galaxies : [Galaxy]
The list of galaxies in the ray-tracing calculation.
image_plane_grid : grid_stacks.GridStack
The image-plane grid which is traced. (includes the grid, sub-grid, blurring-grid, etc.).
planes_between_lenses : [int]
The number of slices between each main plane. The first entry in this list determines the number of slices \
between Earth (redshift 0.0) and main plane 0, the next between main planes 0 and 1, etc.
border : masks.GridBorder
The border of the grid, which is used to relocate demagnified traced pixels to the \
source-plane borders.
cosmology : astropy.cosmology
The cosmology of the ray-tracing calculation.
"""
lens_redshifts = plane_util.ordered_plane_redshifts_from(
galaxies=lens_galaxies)
plane_redshifts = plane_util.ordered_plane_redshifts_with_slicing_from(
lens_redshifts=lens_redshifts,
planes_between_lenses=planes_between_lenses,
source_plane_redshift=source_galaxies[0].redshift,
)
galaxies_in_planes = plane_util.galaxies_in_redshift_ordered_planes_from(
galaxies=lens_galaxies + line_of_sight_galaxies,
plane_redshifts=plane_redshifts,
)
plane_redshifts.append(source_galaxies[0].redshift)
galaxies_in_planes.append(source_galaxies)
planes = []
for plane_index in range(0, len(plane_redshifts)):
planes.append(
pl.Plane(
redshift=plane_redshifts[plane_index],
galaxies=galaxies_in_planes[plane_index],
))
return Tracer(planes=planes, cosmology=cosmology)
