94 lines
2.4 KiB
Python
94 lines
2.4 KiB
Python
from collections import namedtuple
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import math
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class I(namedtuple('Imprecise', 'value, delta')):
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'Imprecise type: I(value=0.0, delta=0.0)'
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__slots__ = ()
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def __new__(_cls, value=0.0, delta=0.0):
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'Defaults to 0.0 ± delta'
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return super().__new__(_cls, float(value), abs(float(delta)))
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def reciprocal(self):
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return I(1. / self.value, self.delta / (self.value**2))
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def __str__(self):
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'Shorter form of Imprecise as string'
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return 'I(%g, %g)' % self
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def __neg__(self):
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return I(-self.value, self.delta)
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def __add__(self, other):
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if type(other) == I:
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return I( self.value + other.value, (self.delta**2 + other.delta**2)**0.5 )
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try:
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c = float(other)
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except:
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return NotImplemented
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return I(self.value + c, self.delta)
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def __sub__(self, other):
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return self + (-other)
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def __radd__(self, other):
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return I.__add__(self, other)
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def __mul__(self, other):
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if type(other) == I:
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#if id(self) == id(other):
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# return self ** 2
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a1,b1 = self
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a2,b2 = other
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f = a1 * a2
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return I( f, f * ( (b1 / a1)**2 + (b2 / a2)**2 )**0.5 )
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try:
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c = float(other)
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except:
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return NotImplemented
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return I(self.value * c, self.delta * c)
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def __pow__(self, other):
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if type(other) == I:
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return NotImplemented
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try:
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c = float(other)
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except:
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return NotImplemented
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f = self.value ** c
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return I(f, f * c * (self.delta / self.value))
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def __rmul__(self, other):
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return I.__mul__(self, other)
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def __truediv__(self, other):
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if type(other) == I:
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return self.__mul__(other.reciprocal())
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try:
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c = float(other)
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except:
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return NotImplemented
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return I(self.value / c, self.delta / c)
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def __rtruediv__(self, other):
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return other * self.reciprocal()
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__div__, __rdiv__ = __truediv__, __rtruediv__
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Imprecise = I
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def distance(p1, p2):
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x1, y1 = p1
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x2, y2 = p2
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return ((x1 - x2)**2 + (y1 - y2)**2)**0.5
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x1 = I(100, 1.1)
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x2 = I(200, 2.2)
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y1 = I( 50, 1.2)
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y2 = I(100, 2.3)
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p1, p2 = (x1, y1), (x2, y2)
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print("Distance between points\n p1: %s\n and p2: %s\n = %r" % (
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p1, p2, distance(p1, p2)))
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