def _n_nearest_items(self, n: int, point: _Point) -> _Iterator[_Item]:
queue = [(0, 0, self._root)]
while n and queue:
_, _, node = _heappop(queue)
for child in node.children:
_heappush(queue,
(child.distance_to_point(point), -child.index -
1 if child.is_leaf else child.index, child))
while n and queue and queue[0][1] < 0:
_, _, node = _heappop(queue)
yield node.item
n -= 1
def pythagorean_triples(n=None):
"""Generate n Pythagorean triples ordered by the value of c ascending. If n
is None or not given, generate infinitly. Default is None.
Examples:
>>> list(pythagorean_triples(5))
[(3, 4, 5), (5, 12, 13), (15, 8, 17), (7, 24, 25), (21, 20, 29)]
"""
iterator = _count() if n is None else range(n)
iterator = iter(iterator)
base_mat = ((1, 2, 2),
(2, 1, 2),
(2, 2, 3))
multiplier = ((1, -1, 1), (1, 1, 1), (-1, 1, 1))
matrices = []
for multip in multiplier:
mat = []
for row, elem in zip(base_mat, multip):
mat.append(tuple(map(lambda e: e * elem, row)))
matrices.append(tuple(mat))
matrices = tuple(matrices)
heap = [(5, (3, 4, 5))]
for i in iterator:
_, triple = _heappop(heap)
yield triple
for matrix in matrices:
next_triple = tuple(map(lambda col: sum(_starmap(_mul,
zip(triple, col))), zip(*matrix)))
_heappush(heap, (next_triple[2], next_triple))
def nearest_item(self, point: _Point) -> _Item:
"""
Searches for index with box in the tree
the nearest to the given point.
Time complexity:
``O(max_children * log size)``
Memory complexity:
``O(max_children * log size)``
where ``size = len(self.boxes)``,
``max_children = self.max_children``.
:param point: input point.
:returns:
index with box in the tree the nearest to the input point.
>>> from ground.base import get_context
>>> context = get_context()
>>> Box, Point = context.box_cls, context.point_cls
>>> boxes = [Box(-index, index, 0, index) for index in range(1, 11)]
>>> tree = Tree(boxes)
>>> tree.nearest_item(Point(0, 0)) == (9, Box(-10, 10, 0, 10))
True
>>> tree.nearest_item(Point(-10, 0)) == (9, Box(-10, 10, 0, 10))
True
>>> tree.nearest_item(Point(-10, 10)) == (9, Box(-10, 10, 0, 10))
True
>>> tree.nearest_item(Point(10, 0)) == (9, Box(-10, 10, 0, 10))
True
>>> tree.nearest_item(Point(10, 10)) == (9, Box(-10, 10, 0, 10))
True
"""
queue = [(0, 0, self._root)]
while queue:
_, _, node = _heappop(queue)
for child in node.children:
_heappush(queue,
(child.distance_to_point(point), -child.index -
1 if child.is_leaf else child.index, child))
if queue and queue[0][1] < 0:
_, _, node = _heappop(queue)
return node.item
def nearest_to_point_item(self, point: _Point) -> _Item:
"""
Searches for index with segment in the tree
the nearest to the given point.
Time complexity:
``O(max_children * log size)``
Memory complexity:
``O(max_children * log size)``
where ``size = len(self.segments)``,
``max_children = self.max_children``.
:param point: input point.
:returns:
index with segment in the tree the nearest to the input point.
>>> from ground.base import get_context
>>> context = get_context()
>>> Point, Segment = context.point_cls, context.segment_cls
>>> segments = [Segment(Point(0, index), Point(index, index))
... for index in range(1, 11)]
>>> tree = Tree(segments)
>>> (tree.nearest_to_point_item(Point(0, 0))
... == (0, Segment(Point(0, 1), Point(1, 1))))
True
"""
queue = [(0, 0, self._root)]
while queue:
_, _, node = _heappop(queue)
for child in node.children:
_heappush(queue,
(child.distance_to_point(point),
child.index if child.is_leaf else -child.index - 1,
child))
if queue and queue[0][1] >= 0:
_, _, node = _heappop(queue)
return node.item
def _get(self):
return _heappop(self.queue)
def call_scheduled_functions(self, dt):
"""Call scheduled functions that elapsed on the last `update_time`.
.. versionadded:: 1.2
:Parameters:
dt : float
The elapsed time since the last update to pass to each
scheduled function. This is *not* used to calculate which
functions have elapsed.
:rtype: bool
:return: True if any functions were called, otherwise False.
"""
now = self.last_ts
result = False # flag indicates if any function was called
# handle items scheduled for every tick
if self._schedule_items:
result = True
# duplicate list in case event unschedules itself
for item in list(self._schedule_items):
item.func(dt, *item.args, **item.kwargs)
# check the next scheduled item that is not called each tick
# if it is scheduled in the future, then exit
interval_items = self._schedule_interval_items
try:
if interval_items[0].next_ts > now:
return result
# raised when the interval_items list is empty
except IndexError:
return result
# NOTE: there is no special handling required to manage things
# that are scheduled during this loop, due to the heap
self._current_interval_item = item = None
get_soft_next_ts = self._get_soft_next_ts
while interval_items:
# the scheduler will hold onto a reference to an item in
# case it needs to be rescheduled. it is more efficient
# to push and pop the heap at once rather than two operations
if item is None:
item = _heappop(interval_items)
else:
item = _heappushpop(interval_items, item)
# a scheduled function may try and unschedule itself
# so we need to keep a reference to the current
# item no longer on heap to be able to check
self._current_interval_item = item
# if next item is scheduled in the future then break
if item.next_ts > now:
break
# execute the callback
try:
item.func(now - item.last_ts, *item.args, **item.kwargs)
except ReferenceError:
pass # weakly-referenced object no longer exists.
if item.interval:
# Try to keep timing regular, even if overslept this time;
# but don't schedule in the past (which could lead to
# infinitely-worsening error).
item.next_ts = item.last_ts + item.interval
item.last_ts = now
# test the schedule for the next execution
if item.next_ts <= now:
# the scheduled time of this item has already passed
# so it must be rescheduled
if now - item.next_ts < 0.05:
# missed execution time by 'reasonable' amount, so
# reschedule at normal interval
item.next_ts = now + item.interval
else:
# missed by significant amount, now many events have
# likely missed execution. do a soft reschedule to
# avoid lumping many events together.
# in this case, the next dt will not be accurate
item.next_ts = get_soft_next_ts(now, item.interval)
item.last_ts = item.next_ts - item.interval
else:
# not an interval, so this item will not be rescheduled
self._current_interval_item = item = None
if item is not None:
_heappush(interval_items, item)
return True
def _get(self):
return _heappop(self.queue)
