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import attr |
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@attr.s |
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class LinearScale: |
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lower_bound = attr.ib(init=True, type=int) |
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upper_bound = attr.ib(init=True, type=int) |
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@upper_bound.validator |
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def __validate_scale(self, attribute, upper_bound): |
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if upper_bound <= self.lower_bound: |
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raise ValueError( |
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f'The linear scale, should have lower_bound < upper_bound. Instead lower_bound={self.lower_bound}, upper_bound={upper_bound}') |
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def __len__(self): |
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"""Returns 2, since the lower and upper bound values are sufficient to define a linear scale""" |
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return 2 |
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@classmethod |
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def create(cls, two_element_list_like): |
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return LinearScale(*[_ for _ in two_element_list_like]) |
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@attr.s |
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class MapOnLinearSpace: |
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_from_scale = attr.ib(init=True, type=LinearScale) |
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_target_scale = attr.ib(init=True, type=LinearScale) |
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_reverse = attr.ib(init=True, default=False, type=bool) |
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_transform_callback = attr.ib(init=False, |
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default=attr.Factory(lambda self: self._get_transform_callback(), takes_self=True)) |
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@classmethod |
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def universal_constructor(cls, from_scale, target_scale, reverse=False): |
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return MapOnLinearSpace(LinearScale.create(from_scale), |
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LinearScale.create(target_scale), |
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reverse) |
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def __transform_inverted(self, number): |
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# F(x) = { ( to_scale_min - to_scale_max ) * x + to_scale_max * from_scale_max - to_scale_min * from_scale_min } / ( from_scale_max - from_scale_min ) |
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return ( (self._target_scale.lower_bound - self._target_scale.upper_bound) * number + self._target_scale.upper_bound * self._from_scale.upper_bound - self._target_scale.lower_bound * self._from_scale.lower_bound ) / ( |
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self._from_scale.upper_bound - self._from_scale.lower_bound) |
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def __transform(self, number): |
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return ((self._target_scale.upper_bound - self._target_scale.lower_bound) * number + self._target_scale.lower_bound * self._from_scale.upper_bound - self._target_scale.lower_bound * self._from_scale.lower_bound) / (self._from_scale.upper_bound - self._from_scale.lower_bound) |
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def _get_transform_callback(self): |
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if self._reverse: |
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return self.__transform_inverted |
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return self.__transform |
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def transform(self, number): |
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"""Transform the input number to a different linear scale""" |
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return self._transform_callback(number) |
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@property |
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def from_scale(self): |
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return self._from_scale |
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@from_scale.setter |
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def from_scale(self, from_scale): |
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self._from_scale = LinearScale.create(from_scale) |
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self._transform_callback = self._get_transform_callback() |
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@property |
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def target_scale(self): |
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return self._target_scale |
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@target_scale.setter |
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def target_scale(self, target_scale): |
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self._target_scale = LinearScale.create(target_scale) |
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self._transform_callback = self._get_transform_callback() |
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@property |
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def reverse(self): |
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return self._reverse |
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@reverse.setter |
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def reverse(self, reverse): |
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self._reverse = reverse |
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self._transform_callback = self._get_transform_callback() |
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boromir674 /
so-magic
