155 lines
3.4 KiB
Python
155 lines
3.4 KiB
Python
#! /usr/bin/env python
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# -*- coding: utf-8 -*-
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# vim:fenc=utf-8
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#
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# Copyright © 2017 lafrite <lafrite@Poivre>
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#
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# Distributed under terms of the MIT license.
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"""
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Divide MO
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"""
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from decimal import Decimal
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from multipledispatch import Dispatcher
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from ..tree import Tree
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from ..MO.mo import MO, MOnumber
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from ..MO.fraction import MOFraction
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from .exceptions import DivideError
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from .filters import special_case
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divide_doc = """ Dividing MOs
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:param left: left MO
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:param right: right MO
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:returns: Tree or MO
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"""
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divide = Dispatcher("divide", doc=divide_doc)
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def divide_filter(left, right):
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""" Automatic divide on MO
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>>> a = MOnumber(4)
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>>> b = MOnumber(1)
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>>> divide(a, b)
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<MOnumber 4>
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>>> a = MOnumber(0)
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>>> b = MOnumber(1)
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>>> divide(a, b)
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<MOnumber 0>
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>>> a = MOnumber(4)
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>>> b = MOnumber(0)
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>>> divide(a, b)
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Traceback (most recent call last):
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...
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mapytex.calculus.core.compute.exceptions.DivideError: Division by zero
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"""
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try:
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if left == 0:
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return left
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except TypeError:
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pass
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try:
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if right == 1:
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return left
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except TypeError:
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pass
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try:
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if right == 0:
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raise DivideError("Division by zero")
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except TypeError:
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pass
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@divide.register(MOnumber, MOnumber)
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@special_case(divide_filter)
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def monumber_monumber(left, right):
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""" Divide 2 monumbers and return a MOFraction
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>>> a = MOnumber(4)
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>>> b = MOnumber(6.2)
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>>> monumber_monumber(a, b)
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<MOnumber 0.6451612903225806266768278939>
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>>> a = MOnumber(4)
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>>> b = MOnumber(6)
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>>> monumber_monumber(a, b)
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Traceback (most recent call last):
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...
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NotImplementedError: Can't divide 2 int. Need to create a Fraction instead
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"""
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if type(left.value) in [float, Decimal] or \
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type(right.value) in [float, Decimal]:
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return MO.factory(left / right)
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else:
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raise NotImplementedError("Can't divide 2 int. Need to create a Fraction instead")
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@divide.register(MOnumber, MOFraction)
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@special_case(divide_filter)
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def monumber_mofraction(left, right):
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""" Divide a monumber and a mofraction by inverting MOFraction
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>>> a = MOnumber(4)
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>>> b = MOFraction(6, 5)
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>>> print(monumber_mofraction(a, b))
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*
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> 4
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> /
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| > 5
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| > 6
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>>> b = MOFraction(6, 5, True)
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>>> print(monumber_mofraction(a, b))
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*
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> 4
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> -
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| > None
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| > /
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| | > 5
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| | > 6
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"""
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return Tree("*", left, right.inverse())
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@divide.register(MOFraction, MOnumber)
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@special_case(divide_filter)
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def mofraction_monumber(left, right):
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""" Divide a monumber and a mofraction by inverting MOnumber
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>>> a = MOFraction(6, 5)
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>>> b = MOnumber(4)
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>>> print(mofraction_monumber(a, b))
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*
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> /
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| > 6
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| > 5
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> /
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| > 1
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| > 4
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"""
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right_fraction = MOFraction(MOnumber(1), right)
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return Tree("*", left, right_fraction)
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@divide.register(MOFraction, MOFraction)
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@special_case(divide_filter)
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def mofraction_mofraction(left, right):
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""" Divide two mofractions by inverting right MOFraction
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>>> a = MOFraction(1, 5)
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>>> b = MOFraction(4, 5)
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>>> print(mofraction_mofraction(a, b))
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*
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> /
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| > 1
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| > 5
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> /
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| > 5
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| > 4
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"""
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return Tree("*", left, right.inverse())
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# -----------------------------
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# Reglages pour 'vim'
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# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
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# cursor: 16 del
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