#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
swinging_door
=============
Implementation of the SwingingDoor algorithm in Python.
"""
from sys import version_info
from typing import TYPE_CHECKING
if TYPE_CHECKING: # pragma: no cover
from typing import Generator, Tuple
__author__ = "Aleksandr F. Mikhaylov (ChelAxe)" # type: str
__version__ = "0.1.1" # type: str
__license__ = "MIT" # type: str
[docs]class Point:
"""
Point in rectangular coordinate system.
"""
[docs] def __init__(self, abscissa, ordinate):
# type: (float, float) -> None
"""
Class constructor specifying the coordinates of the point.
:param float abscissa: point abscissa;
:param float ordinate: point ordinate.
>>> Point(1.0, 2.0)
Point(1.0, 2.0)
"""
self.abscissa = abscissa
self.ordinate = ordinate
[docs] def __call__(self):
# type: () -> Tuple[float, float]
"""
A call that returns the coordinates of a point.
:rtype: Tuple[float, float]
:return: Point coordinates.
>>> Point(1.0, 2.0)()
(1.0, 2.0)
"""
return self.abscissa, self.ordinate
[docs] def __repr__(self): # type: () -> str
"""
Unambiguous textual representation of an object.
:rtype: str
:return: Unambiguous textual representation of an object.
>>> repr(Point(1.0, 2.0))
'Point(1.0, 2.0)'
"""
return "Point({abscissa}, {ordinate})".format(
abscissa=self.abscissa, ordinate=self.ordinate
)
[docs] def __str__(self): # type: () -> str
"""
Natural textual representation of the object.
:rtype: str
:return: Natural textual representation of the object.
>>> str(Point(1.0, 2.0))
'(1.0, 2.0)'
"""
return "({abscissa}, {ordinate})".format(
abscissa=self.abscissa, ordinate=self.ordinate
)
[docs]def swinging_door(
data, # type: Generator[Tuple[float, float], None, None]
deviation=0.1, # type: float
):
# type: (...) -> Generator[Tuple[float, float], None, None]
"""
Implementation of the SwingingDoor algorithm.
:param Generator[Tuple[float,float],None,None] data: data;
:param float deviation: compression deflection.
:rtype: Generator[Tuple[float, float], None, None]
:return: Compressed data.
>>> def data(values):
... x = 0.0
... for y in values:
... yield x, y
... x += 1.0
>>> tuple(swinging_door(data([
... 2.1, 3.1, 4.1, 4.6
... ]), deviation=0.1))
((0.0, 2.1), (2.444444444444445, 4.372222222222222))
>>> tuple(swinging_door(data([
... 4.1, 3.1, 2.1, 4.6
... ]), deviation=0.1))
((0.0, 4.1), (2.088235294117647, 2.270588235294118))
"""
entrance = current = Point(
*(
data.__next__()
if version_info.major > 2
else data.next() # type: ignore
)
) # type: Point
upper_pivot = Point(
entrance.abscissa, entrance.ordinate + deviation
) # type: Point
lower_pivot = Point(
entrance.abscissa, entrance.ordinate - deviation
) # type: Point
sloping_upper_max = sloping_lower_min = 0.0 # type: float
yield entrance()
while True:
past = current # type: Point
try:
current = Point(
*(
data.__next__()
if version_info.major > 2
else data.next() # type: ignore
)
)
except StopIteration:
break
sloping_upper = (current.ordinate - upper_pivot.ordinate) / (
current.abscissa - upper_pivot.abscissa
) # type: float
sloping_lower = (current.ordinate - lower_pivot.ordinate) / (
current.abscissa - lower_pivot.abscissa
) # type: float
if not sloping_upper_max and not sloping_lower_min:
sloping_upper_max = sloping_upper
sloping_lower_min = sloping_lower
continue
if sloping_upper > sloping_upper_max:
sloping_upper_max = sloping_upper
if sloping_upper_max > sloping_lower_min:
sloping_entrance = (current.ordinate - past.ordinate) / (
current.abscissa - past.abscissa
) # type: float
entrance_upper = (
upper_pivot.ordinate
- past.ordinate
+ sloping_entrance * past.abscissa
- sloping_lower_min * upper_pivot.abscissa
) / (
sloping_entrance - sloping_lower_min
) # type: float
entrance = Point(
entrance_upper,
upper_pivot.ordinate
+ sloping_lower_min
* (entrance_upper - upper_pivot.abscissa)
- deviation / 2,
)
yield entrance()
upper_pivot = Point(
entrance.abscissa, entrance.ordinate + deviation
)
lower_pivot = Point(
entrance.abscissa, entrance.ordinate - deviation
)
sloping_upper_max = sloping_upper = (
current.ordinate - upper_pivot.ordinate
) / (current.abscissa - upper_pivot.abscissa)
sloping_lower_min = sloping_lower = (
current.ordinate - lower_pivot.ordinate
) / (current.abscissa - lower_pivot.abscissa)
elif sloping_lower < sloping_lower_min:
sloping_lower_min = sloping_lower
if sloping_upper_max > sloping_lower_min:
sloping_entrance = (current.ordinate - past.ordinate) / (
current.abscissa - past.abscissa
)
entrance_lower = (
lower_pivot.ordinate
- past.ordinate
+ sloping_entrance * past.abscissa
- sloping_upper_max * lower_pivot.abscissa
) / (sloping_entrance - sloping_upper_max)
entrance = Point(
entrance_lower,
lower_pivot.ordinate
+ sloping_upper_max
* (entrance_lower - lower_pivot.abscissa)
+ deviation / 2,
)
yield entrance()
upper_pivot = Point(
entrance.abscissa, entrance.ordinate + deviation
)
lower_pivot = Point(
entrance.abscissa, entrance.ordinate - deviation
)
sloping_upper_max = sloping_upper = (
current.ordinate - upper_pivot.ordinate
) / (current.abscissa - upper_pivot.abscissa)
sloping_lower_min = sloping_lower = (
current.ordinate - lower_pivot.ordinate
) / (current.abscissa - lower_pivot.abscissa)
