def __select_random_location_with_points(
self,
request,
lcm_shift_roi,
lcm_voxel_size):
request_points_roi = request[self.ensure_nonempty].roi
while True:
# How to pick shifts that ensure that a randomly chosen point is
# contained in the request ROI:
#
#
# request point
# [---------) .
# 0 +10 17
#
# least shifted to contain point
# [---------)
# 8 +10
# ==
# point-request.begin-request.shape+1
#
# most shifted to contain point:
# [---------)
# 17 +10
# ==
# point-request.begin
#
# all possible shifts
# [---------)
# 8 +10
# ==
# point-request.begin-request.shape+1
# ==
# request.shape
#
# In the most shifted scenario, it could happen that the point lies
# exactly at the lower boundary (17 in the example). This will cause
# trouble if later we mirror the batch. The point would end up lying
# on the other boundary, which is exclusive and thus not part of the
# ROI. Therefore, we have to ensure that the point is well inside
# the shifted ROI, not just on the boundary:
#
# all possible shifts
# [--------)
# 8 +9
# ==
# request.shape-1
# pick a random point
point_id = choice(self.points.data.keys())
point = self.points.data[point_id]
logger.debug(
"select random point %d at %s",
point_id,
point.location)
# get the lcm voxel that contains this point
lcm_location = Coordinate(point.location/lcm_voxel_size)
logger.debug(
"belongs to lcm voxel %s",
lcm_location)
# mark all dimensions in which the point lies on the lower boundary
# of the lcm voxel
on_lower_boundary = lcm_location*lcm_voxel_size == point.location
logger.debug(
"lies on the lower boundary of the lcm voxel in dimensions %s",
on_lower_boundary)
# for each of these dimensions, we have to change the shape of the
# shift ROI using the following correction
lower_boundary_correction = Coordinate((
-1 if o else 0
for o in on_lower_boundary
))
logger.debug(
"lower bound correction for shape of shift ROI %s",
lower_boundary_correction)
# get the request ROI's shape in lcm
lcm_roi_begin = request_points_roi.get_begin()/lcm_voxel_size
lcm_roi_shape = request_points_roi.get_shape()/lcm_voxel_size
logger.debug("Point request ROI: %s", request_points_roi)
logger.debug("Point request lcm ROI shape: %s", lcm_roi_shape)
# get all possible starting points of lcm_roi_shape that contain
# lcm_location
lcm_shift_roi_begin = (
lcm_location - lcm_roi_begin - lcm_roi_shape +
Coordinate((1,)*len(lcm_location))
)
lcm_shift_roi_shape = (
lcm_roi_shape + lower_boundary_correction
)
lcm_point_shift_roi = Roi(lcm_shift_roi_begin, lcm_shift_roi_shape)
logger.debug("lcm point shift roi: %s", lcm_point_shift_roi)
# intersect with total shift ROI
if not lcm_point_shift_roi.intersects(lcm_shift_roi):
logger.debug(
"reject random shift, random point %s shift ROI %s does "
"not intersect total shift ROI %s", point.location,
lcm_point_shift_roi, lcm_shift_roi)
continue
lcm_point_shift_roi = lcm_point_shift_roi.intersect(lcm_shift_roi)
# select a random shift from all possible shifts
random_shift = self.__select_random_location(
lcm_point_shift_roi,
lcm_voxel_size)
logger.debug("random shift: %s", random_shift)
# count all points inside the shifted ROI
points_request = BatchRequest()
points_request[self.ensure_nonempty] = PointsSpec(
roi=request_points_roi.shift(random_shift))
logger.debug("points request: %s", points_request)
points_batch = self.get_upstream_provider().request_batch(points_request)
point_ids = points_batch.points[self.ensure_nonempty].data.keys()
assert point_id in point_ids, (
"Requested batch to contain point %s, but got points "
"%s"%(point_id, point_ids))
num_points = len(point_ids)
# accept this shift with p=1/num_points
#
# This is to compensate the bias introduced by close-by points.
accept = random() <= 1.0/num_points
if accept:
return random_shift
def __select_random_location_with_points(
self,
request,
lcm_shift_roi,
lcm_voxel_size):
request_points = request.graph_specs.get(self.ensure_nonempty)
if request_points is None:
total_roi = request.get_total_roi()
logger.warning(
f"Requesting non empty {self.ensure_nonempty}, however {self.ensure_nonempty} "
f"has not been requested. Falling back on using the total roi of the "
f"request {total_roi} for {self.ensure_nonempty}."
)
request_points_roi = total_roi
else:
request_points_roi = request_points.roi
while True:
# How to pick shifts that ensure that a randomly chosen point is
# contained in the request ROI:
#
#
# request point
# [---------) .
# 0 +10 17
#
# least shifted to contain point
# [---------)
# 8 +10
# ==
# point-request.begin-request.shape+1
#
# most shifted to contain point:
# [---------)
# 17 +10
# ==
# point-request.begin
#
# all possible shifts
# [---------)
# 8 +10
# ==
# point-request.begin-request.shape+1
# ==
# request.shape
# pick a random point
point = choices(self.points.data, cum_weights=self.cumulative_weights)[0]
logger.debug("select random point at %s", point)
# get the lcm voxel that contains this point
lcm_location = Coordinate(point/lcm_voxel_size)
logger.debug(
"belongs to lcm voxel %s",
lcm_location)
# get the request ROI's shape in lcm
lcm_roi_begin = request_points_roi.get_begin()/lcm_voxel_size
lcm_roi_shape = request_points_roi.get_shape()/lcm_voxel_size
logger.debug("Point request ROI: %s", request_points_roi)
logger.debug("Point request lcm ROI shape: %s", lcm_roi_shape)
# get all possible starting points of lcm_roi_shape that contain
# lcm_location
if self.ensure_centered:
lcm_shift_roi_begin = (
lcm_location
- lcm_roi_begin
- lcm_roi_shape / 2
+ Coordinate((1,) * len(lcm_location))
)
lcm_shift_roi_shape = Coordinate((1,) * len(lcm_location))
else:
lcm_shift_roi_begin = (
lcm_location - lcm_roi_begin - lcm_roi_shape +
Coordinate((1,)*len(lcm_location))
)
lcm_shift_roi_shape = lcm_roi_shape
lcm_point_shift_roi = Roi(lcm_shift_roi_begin, lcm_shift_roi_shape)
logger.debug("lcm point shift roi: %s", lcm_point_shift_roi)
# intersect with total shift ROI
if not lcm_point_shift_roi.intersects(lcm_shift_roi):
logger.debug(
"reject random shift, random point %s shift ROI %s does "
"not intersect total shift ROI %s", point,
lcm_point_shift_roi, lcm_shift_roi)
continue
lcm_point_shift_roi = lcm_point_shift_roi.intersect(lcm_shift_roi)
# select a random shift from all possible shifts
random_shift = self.__select_random_location(
lcm_point_shift_roi,
lcm_voxel_size)
logger.debug("random shift: %s", random_shift)
# count all points inside the shifted ROI
points = self.__get_points_in_roi(
request_points_roi.shift(random_shift))
assert point in points, (
"Requested batch to contain point %s, but got points "
"%s"%(point, points))
num_points = len(points)
return random_shift