def candidate_solutions(self, sourcePos_x, sourcePos_y, kwargs_lens, min_distance=0.1, search_window=10,
verbose=False, x_center=0, y_center=0):
"""
finds pixels in the image plane possibly hosting a solution of the lens equation, for the given source position and lens model
:param sourcePos_x: source position in units of angle
:param sourcePos_y: source position in units of angle
:param kwargs_lens: lens model parameters as keyword arguments
:param min_distance: minimum separation to consider for two images in units of angle
:param search_window: window size to be considered by the solver. Will not find image position outside this window
:param verbose: bool, if True, prints some useful information for the user
:param x_center: float, center of the window to search for point sources
:param y_center: float, center of the window to search for point sources
:returns: (approximate) angular position of (multiple) images ra_pos, dec_pos in units of angles, related ray-traced source displacements and pixel width
:raises: AttributeError, KeyError
"""
kwargs_lens = self.lensModel.set_static(kwargs_lens)
# compute number of pixels to cover the search window with the required min_distance
numPix = int(round(search_window / min_distance) + 0.5)
x_grid, y_grid = util.make_grid(numPix, min_distance)
x_grid += x_center
y_grid += y_center
# ray-shoot to find the relative distance to the required source position for each grid point
x_mapped, y_mapped = self.lensModel.ray_shooting(x_grid, y_grid, kwargs_lens)
absmapped = util.displaceAbs(x_mapped, y_mapped, sourcePos_x, sourcePos_y)
# select minima in the grid points and select grid points that do not deviate more than the
# width of the grid point to a solution of the lens equation
x_mins, y_mins, delta_map = util.neighborSelect(absmapped, x_grid, y_grid)
# pixel width
pixel_width = x_grid[1]-x_grid[0]
return x_mins, y_mins, delta_map, pixel_width
def test_displaceAbs():
x = np.array([0, 1, 2])
y = np.array([3, 2, 1])
sourcePos_x = 1
sourcePos_y = 2
result = util.displaceAbs(x, y, sourcePos_x, sourcePos_y)
assert result[0] == np.sqrt(2)
assert result[1] == 0
def image_position_from_source(self,
sourcePos_x,
sourcePos_y,
kwargs_lens,
min_distance=0.01,
search_window=5,
precision_limit=10**(-10),
num_iter_max=100):
"""
finds image position source position and lense model
:param sourcePos_x: source position in units of angle
:param sourcePos_y: source position in units of angle
:param kwargs_lens: lens model parameters as keyword arguments
:param min_distance: minimum separation to consider for two images in units of angle
:param search_window: window size to be considered by the solver. Will not find image position outside this window
:param precision_limit: required precision in the lens equation solver (in units of angle in the source plane).
:param num_iter_max: maximum iteration of lens-source mapping conducted by solver to match the required precision
:returns: (exact) angular position of (multiple) images ra_pos, dec_pos in units of angle
:raises: AttributeError, KeyError
"""
# compute number of pixels to cover the search window with the required min_distance
numPix = int(round(search_window / min_distance) + 0.5)
x_grid, y_grid = util.make_grid(numPix, min_distance)
# ray-shoot to find the relative distance to the required source position for each grid point
x_mapped, y_mapped = self.lensModel.ray_shooting(
x_grid, y_grid, kwargs_lens)
absmapped = util.displaceAbs(x_mapped, y_mapped, sourcePos_x,
sourcePos_y)
# select minima in the grid points and select grid points that do not deviate more than the
# width of the grid point to a solution of the lens equation
x_mins, y_mins, delta_map = util.neighborSelect(
absmapped, x_grid, y_grid)
x_mins = x_mins[delta_map <= min_distance]
y_mins = y_mins[delta_map <= min_distance]
# iterative solving of the lens equation for the selected grid points
x_mins, y_mins, solver_precision = self._findIterative(
x_mins, y_mins, sourcePos_x, sourcePos_y, kwargs_lens,
precision_limit, num_iter_max)
# only select iterative results that match the precision limit
x_mins = x_mins[solver_precision <= precision_limit]
y_mins = y_mins[solver_precision <= precision_limit]
# find redundant solutions within the min_distance criterion
x_mins, y_mins = image_util.findOverlap(x_mins, y_mins, min_distance)
x_mins, y_mins = self.sort_arrival_times(x_mins, y_mins, kwargs_lens)
#x_mins, y_mins = lenstronomy_util.coordInImage(x_mins, y_mins, numPix, deltapix)
return x_mins, y_mins
def image_position_from_source(self,
sourcePos_x,
sourcePos_y,
kwargs_lens,
min_distance=0.1,
search_window=10,
precision_limit=10**(-10),
num_iter_max=100,
arrival_time_sort=True,
initial_guess_cut=True,
verbose=False,
x_center=0,
y_center=0,
num_random=0,
non_linear=False,
magnification_limit=None):
"""
finds image position source position and lense model
:param sourcePos_x: source position in units of angle
:param sourcePos_y: source position in units of angle
:param kwargs_lens: lens model parameters as keyword arguments
:param min_distance: minimum separation to consider for two images in units of angle
:param search_window: window size to be considered by the solver. Will not find image position outside this window
:param precision_limit: required precision in the lens equation solver (in units of angle in the source plane).
:param num_iter_max: maximum iteration of lens-source mapping conducted by solver to match the required precision
:param arrival_time_sort: bool, if True, sorts image position in arrival time (first arrival photon first listed)
:param initial_guess_cut: bool, if True, cuts initial local minima selected by the grid search based on distance criteria from the source position
:param verbose: bool, if True, prints some useful information for the user
:param x_center: float, center of the window to search for point sources
:param y_center: float, center of the window to search for point sources
:param non_linear: bool, if True applies a non-linear solver not dependent on Hessian computation
:returns: (exact) angular position of (multiple) images ra_pos, dec_pos in units of angle
:raises: AttributeError, KeyError
"""
kwargs_lens = self._static_lens_settings(kwargs_lens)
# compute number of pixels to cover the search window with the required min_distance
numPix = int(round(search_window / min_distance) + 0.5)
x_grid, y_grid = util.make_grid(numPix, min_distance)
x_grid += x_center
y_grid += y_center
# ray-shoot to find the relative distance to the required source position for each grid point
x_mapped, y_mapped = self.lensModel.ray_shooting(
x_grid, y_grid, kwargs_lens)
absmapped = util.displaceAbs(x_mapped, y_mapped, sourcePos_x,
sourcePos_y)
# select minima in the grid points and select grid points that do not deviate more than the
# width of the grid point to a solution of the lens equation
x_mins, y_mins, delta_map = util.neighborSelect(
absmapped, x_grid, y_grid)
if verbose is True:
print(
"There are %s regions identified that could contain a solution of the lens equation"
% len(x_mins))
#mag = np.abs(mag)
#print(x_mins, y_mins, 'before requirement of min_distance')
if len(x_mins) < 1:
return x_mins, y_mins
if initial_guess_cut is True:
mag = np.abs(
self.lensModel.magnification(x_mins, y_mins, kwargs_lens))
mag[mag < 1] = 1
x_mins = x_mins[delta_map <= min_distance * mag * 5]
y_mins = y_mins[delta_map <= min_distance * mag * 5]
if verbose is True:
print(
"The number of regions that meet the plausibility criteria are %s"
% len(x_mins))
x_mins = np.append(
x_mins,
np.random.uniform(low=-search_window / 2 + x_center,
high=search_window / 2 + x_center,
size=num_random))
y_mins = np.append(
y_mins,
np.random.uniform(low=-search_window / 2 + y_center,
high=search_window / 2 + y_center,
size=num_random))
# iterative solving of the lens equation for the selected grid points
x_mins, y_mins, solver_precision = self._findIterative(
x_mins,
y_mins,
sourcePos_x,
sourcePos_y,
kwargs_lens,
precision_limit,
num_iter_max,
verbose=verbose,
min_distance=min_distance,
non_linear=non_linear)
# only select iterative results that match the precision limit
x_mins = x_mins[solver_precision <= precision_limit]
y_mins = y_mins[solver_precision <= precision_limit]
# find redundant solutions within the min_distance criterion
x_mins, y_mins = image_util.findOverlap(x_mins, y_mins, min_distance)
if arrival_time_sort is True:
x_mins, y_mins = self.sort_arrival_times(x_mins, y_mins,
kwargs_lens)
self._make_dynamic()
if magnification_limit is not None:
mag = np.abs(
self.lensModel.magnification(x_mins, y_mins, kwargs_lens))
x_mins = x_mins[mag >= magnification_limit]
y_mins = y_mins[mag >= magnification_limit]
return x_mins, y_mins
def image_position_from_source(self,
sourcePos_x,
sourcePos_y,
kwargs_lens,
min_distance=0.1,
search_window=10,
precision_limit=10**(-10),
num_iter_max=100,
arrival_time_sort=True,
initial_guess_cut=True,
verbose=False):
"""
finds image position source position and lense model
:param sourcePos_x: source position in units of angle
:param sourcePos_y: source position in units of angle
:param kwargs_lens: lens model parameters as keyword arguments
:param min_distance: minimum separation to consider for two images in units of angle
:param search_window: window size to be considered by the solver. Will not find image position outside this window
:param precision_limit: required precision in the lens equation solver (in units of angle in the source plane).
:param num_iter_max: maximum iteration of lens-source mapping conducted by solver to match the required precision
:param arrival_time_sort: bool, if True, sorts image position in arrival time (first arrival photon first listed)
:param initial_guess_cut: bool, if True, cuts initial local minima selected by the grid search based on
distance criteria from the source position
:returns: (exact) angular position of (multiple) images ra_pos, dec_pos in units of angle
:raises: AttributeError, KeyError
"""
# compute number of pixels to cover the search window with the required min_distance
numPix = int(round(search_window / min_distance) + 0.5)
x_grid, y_grid = util.make_grid(numPix, min_distance)
# ray-shoot to find the relative distance to the required source position for each grid point
x_mapped, y_mapped = self.lensModel.ray_shooting(
x_grid, y_grid, kwargs_lens)
absmapped = util.displaceAbs(x_mapped, y_mapped, sourcePos_x,
sourcePos_y)
# select minima in the grid points and select grid points that do not deviate more than the
# width of the grid point to a solution of the lens equation
x_mins, y_mins, delta_map = util.neighborSelect(
absmapped, x_grid, y_grid)
if verbose is True:
print(
"There are %s regions identified that could contain a solution of the lens equation"
% len(x_mins))
#mag = np.abs(mag)
#print(x_mins, y_mins, 'before requirement of min_distance')
if initial_guess_cut is True:
mag = np.abs(
self.lensModel.magnification(x_mins, y_mins, kwargs_lens))
x_mins = x_mins[delta_map <= min_distance * mag * 5]
y_mins = y_mins[delta_map <= min_distance * mag * 5]
if verbose is True:
print(
"The number of regions that meet the plausibility criteria are %s"
% len(x_mins))
#print(x_mins, y_mins, 'after requirement of min_distance')
# iterative solving of the lens equation for the selected grid points
x_mins, y_mins, solver_precision = self._findIterative(x_mins,
y_mins,
sourcePos_x,
sourcePos_y,
kwargs_lens,
precision_limit,
num_iter_max,
verbose=verbose)
# only select iterative results that match the precision limit
x_mins = x_mins[solver_precision <= precision_limit]
y_mins = y_mins[solver_precision <= precision_limit]
#print(x_mins, y_mins, 'after precision limit requirement')
# find redundant solutions within the min_distance criterion
x_mins, y_mins = image_util.findOverlap(x_mins, y_mins, min_distance)
#print(x_mins, y_mins, 'after overlap removals')
if arrival_time_sort is True:
x_mins, y_mins = self.sort_arrival_times(x_mins, y_mins,
kwargs_lens)
#x_mins, y_mins = lenstronomy_util.coordInImage(x_mins, y_mins, numPix, deltapix)
return x_mins, y_mins
