1 | n/a | # Copyright 2007 Google, Inc. All Rights Reserved. |
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2 | n/a | # Licensed to PSF under a Contributor Agreement. |
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3 | n/a | |
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4 | n/a | """Abstract Base Classes (ABCs) for numbers, according to PEP 3141. |
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5 | n/a | |
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6 | n/a | TODO: Fill out more detailed documentation on the operators.""" |
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7 | n/a | |
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8 | n/a | from abc import ABCMeta, abstractmethod |
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9 | n/a | |
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10 | n/a | __all__ = ["Number", "Complex", "Real", "Rational", "Integral"] |
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11 | n/a | |
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12 | n/a | class Number(metaclass=ABCMeta): |
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13 | n/a | """All numbers inherit from this class. |
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14 | n/a | |
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15 | n/a | If you just want to check if an argument x is a number, without |
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16 | n/a | caring what kind, use isinstance(x, Number). |
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17 | n/a | """ |
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18 | n/a | __slots__ = () |
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19 | n/a | |
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20 | n/a | # Concrete numeric types must provide their own hash implementation |
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21 | n/a | __hash__ = None |
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22 | n/a | |
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23 | n/a | |
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24 | n/a | ## Notes on Decimal |
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25 | n/a | ## ---------------- |
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26 | n/a | ## Decimal has all of the methods specified by the Real abc, but it should |
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27 | n/a | ## not be registered as a Real because decimals do not interoperate with |
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28 | n/a | ## binary floats (i.e. Decimal('3.14') + 2.71828 is undefined). But, |
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29 | n/a | ## abstract reals are expected to interoperate (i.e. R1 + R2 should be |
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30 | n/a | ## expected to work if R1 and R2 are both Reals). |
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31 | n/a | |
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32 | n/a | class Complex(Number): |
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33 | n/a | """Complex defines the operations that work on the builtin complex type. |
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34 | n/a | |
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35 | n/a | In short, those are: a conversion to complex, .real, .imag, +, -, |
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36 | n/a | *, /, abs(), .conjugate, ==, and !=. |
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37 | n/a | |
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38 | n/a | If it is given heterogenous arguments, and doesn't have special |
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39 | n/a | knowledge about them, it should fall back to the builtin complex |
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40 | n/a | type as described below. |
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41 | n/a | """ |
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42 | n/a | |
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43 | n/a | __slots__ = () |
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44 | n/a | |
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45 | n/a | @abstractmethod |
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46 | n/a | def __complex__(self): |
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47 | n/a | """Return a builtin complex instance. Called for complex(self).""" |
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48 | n/a | |
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49 | n/a | def __bool__(self): |
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50 | n/a | """True if self != 0. Called for bool(self).""" |
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51 | n/a | return self != 0 |
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52 | n/a | |
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53 | n/a | @property |
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54 | n/a | @abstractmethod |
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55 | n/a | def real(self): |
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56 | n/a | """Retrieve the real component of this number. |
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57 | n/a | |
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58 | n/a | This should subclass Real. |
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59 | n/a | """ |
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60 | n/a | raise NotImplementedError |
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61 | n/a | |
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62 | n/a | @property |
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63 | n/a | @abstractmethod |
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64 | n/a | def imag(self): |
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65 | n/a | """Retrieve the imaginary component of this number. |
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66 | n/a | |
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67 | n/a | This should subclass Real. |
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68 | n/a | """ |
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69 | n/a | raise NotImplementedError |
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70 | n/a | |
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71 | n/a | @abstractmethod |
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72 | n/a | def __add__(self, other): |
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73 | n/a | """self + other""" |
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74 | n/a | raise NotImplementedError |
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75 | n/a | |
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76 | n/a | @abstractmethod |
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77 | n/a | def __radd__(self, other): |
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78 | n/a | """other + self""" |
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79 | n/a | raise NotImplementedError |
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80 | n/a | |
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81 | n/a | @abstractmethod |
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82 | n/a | def __neg__(self): |
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83 | n/a | """-self""" |
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84 | n/a | raise NotImplementedError |
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85 | n/a | |
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86 | n/a | @abstractmethod |
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87 | n/a | def __pos__(self): |
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88 | n/a | """+self""" |
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89 | n/a | raise NotImplementedError |
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90 | n/a | |
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91 | n/a | def __sub__(self, other): |
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92 | n/a | """self - other""" |
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93 | n/a | return self + -other |
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94 | n/a | |
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95 | n/a | def __rsub__(self, other): |
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96 | n/a | """other - self""" |
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97 | n/a | return -self + other |
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98 | n/a | |
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99 | n/a | @abstractmethod |
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100 | n/a | def __mul__(self, other): |
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101 | n/a | """self * other""" |
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102 | n/a | raise NotImplementedError |
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103 | n/a | |
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104 | n/a | @abstractmethod |
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105 | n/a | def __rmul__(self, other): |
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106 | n/a | """other * self""" |
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107 | n/a | raise NotImplementedError |
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108 | n/a | |
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109 | n/a | @abstractmethod |
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110 | n/a | def __truediv__(self, other): |
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111 | n/a | """self / other: Should promote to float when necessary.""" |
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112 | n/a | raise NotImplementedError |
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113 | n/a | |
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114 | n/a | @abstractmethod |
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115 | n/a | def __rtruediv__(self, other): |
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116 | n/a | """other / self""" |
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117 | n/a | raise NotImplementedError |
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118 | n/a | |
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119 | n/a | @abstractmethod |
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120 | n/a | def __pow__(self, exponent): |
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121 | n/a | """self**exponent; should promote to float or complex when necessary.""" |
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122 | n/a | raise NotImplementedError |
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123 | n/a | |
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124 | n/a | @abstractmethod |
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125 | n/a | def __rpow__(self, base): |
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126 | n/a | """base ** self""" |
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127 | n/a | raise NotImplementedError |
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128 | n/a | |
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129 | n/a | @abstractmethod |
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130 | n/a | def __abs__(self): |
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131 | n/a | """Returns the Real distance from 0. Called for abs(self).""" |
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132 | n/a | raise NotImplementedError |
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133 | n/a | |
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134 | n/a | @abstractmethod |
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135 | n/a | def conjugate(self): |
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136 | n/a | """(x+y*i).conjugate() returns (x-y*i).""" |
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137 | n/a | raise NotImplementedError |
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138 | n/a | |
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139 | n/a | @abstractmethod |
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140 | n/a | def __eq__(self, other): |
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141 | n/a | """self == other""" |
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142 | n/a | raise NotImplementedError |
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143 | n/a | |
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144 | n/a | Complex.register(complex) |
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145 | n/a | |
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146 | n/a | |
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147 | n/a | class Real(Complex): |
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148 | n/a | """To Complex, Real adds the operations that work on real numbers. |
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149 | n/a | |
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150 | n/a | In short, those are: a conversion to float, trunc(), divmod, |
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151 | n/a | %, <, <=, >, and >=. |
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152 | n/a | |
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153 | n/a | Real also provides defaults for the derived operations. |
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154 | n/a | """ |
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155 | n/a | |
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156 | n/a | __slots__ = () |
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157 | n/a | |
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158 | n/a | @abstractmethod |
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159 | n/a | def __float__(self): |
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160 | n/a | """Any Real can be converted to a native float object. |
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161 | n/a | |
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162 | n/a | Called for float(self).""" |
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163 | n/a | raise NotImplementedError |
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164 | n/a | |
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165 | n/a | @abstractmethod |
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166 | n/a | def __trunc__(self): |
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167 | n/a | """trunc(self): Truncates self to an Integral. |
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168 | n/a | |
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169 | n/a | Returns an Integral i such that: |
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170 | n/a | * i>0 iff self>0; |
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171 | n/a | * abs(i) <= abs(self); |
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172 | n/a | * for any Integral j satisfying the first two conditions, |
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173 | n/a | abs(i) >= abs(j) [i.e. i has "maximal" abs among those]. |
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174 | n/a | i.e. "truncate towards 0". |
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175 | n/a | """ |
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176 | n/a | raise NotImplementedError |
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177 | n/a | |
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178 | n/a | @abstractmethod |
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179 | n/a | def __floor__(self): |
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180 | n/a | """Finds the greatest Integral <= self.""" |
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181 | n/a | raise NotImplementedError |
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182 | n/a | |
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183 | n/a | @abstractmethod |
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184 | n/a | def __ceil__(self): |
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185 | n/a | """Finds the least Integral >= self.""" |
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186 | n/a | raise NotImplementedError |
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187 | n/a | |
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188 | n/a | @abstractmethod |
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189 | n/a | def __round__(self, ndigits=None): |
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190 | n/a | """Rounds self to ndigits decimal places, defaulting to 0. |
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191 | n/a | |
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192 | n/a | If ndigits is omitted or None, returns an Integral, otherwise |
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193 | n/a | returns a Real. Rounds half toward even. |
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194 | n/a | """ |
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195 | n/a | raise NotImplementedError |
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196 | n/a | |
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197 | n/a | def __divmod__(self, other): |
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198 | n/a | """divmod(self, other): The pair (self // other, self % other). |
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199 | n/a | |
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200 | n/a | Sometimes this can be computed faster than the pair of |
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201 | n/a | operations. |
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202 | n/a | """ |
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203 | n/a | return (self // other, self % other) |
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204 | n/a | |
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205 | n/a | def __rdivmod__(self, other): |
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206 | n/a | """divmod(other, self): The pair (self // other, self % other). |
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207 | n/a | |
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208 | n/a | Sometimes this can be computed faster than the pair of |
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209 | n/a | operations. |
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210 | n/a | """ |
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211 | n/a | return (other // self, other % self) |
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212 | n/a | |
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213 | n/a | @abstractmethod |
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214 | n/a | def __floordiv__(self, other): |
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215 | n/a | """self // other: The floor() of self/other.""" |
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216 | n/a | raise NotImplementedError |
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217 | n/a | |
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218 | n/a | @abstractmethod |
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219 | n/a | def __rfloordiv__(self, other): |
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220 | n/a | """other // self: The floor() of other/self.""" |
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221 | n/a | raise NotImplementedError |
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222 | n/a | |
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223 | n/a | @abstractmethod |
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224 | n/a | def __mod__(self, other): |
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225 | n/a | """self % other""" |
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226 | n/a | raise NotImplementedError |
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227 | n/a | |
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228 | n/a | @abstractmethod |
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229 | n/a | def __rmod__(self, other): |
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230 | n/a | """other % self""" |
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231 | n/a | raise NotImplementedError |
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232 | n/a | |
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233 | n/a | @abstractmethod |
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234 | n/a | def __lt__(self, other): |
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235 | n/a | """self < other |
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236 | n/a | |
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237 | n/a | < on Reals defines a total ordering, except perhaps for NaN.""" |
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238 | n/a | raise NotImplementedError |
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239 | n/a | |
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240 | n/a | @abstractmethod |
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241 | n/a | def __le__(self, other): |
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242 | n/a | """self <= other""" |
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243 | n/a | raise NotImplementedError |
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244 | n/a | |
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245 | n/a | # Concrete implementations of Complex abstract methods. |
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246 | n/a | def __complex__(self): |
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247 | n/a | """complex(self) == complex(float(self), 0)""" |
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248 | n/a | return complex(float(self)) |
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249 | n/a | |
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250 | n/a | @property |
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251 | n/a | def real(self): |
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252 | n/a | """Real numbers are their real component.""" |
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253 | n/a | return +self |
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254 | n/a | |
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255 | n/a | @property |
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256 | n/a | def imag(self): |
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257 | n/a | """Real numbers have no imaginary component.""" |
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258 | n/a | return 0 |
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259 | n/a | |
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260 | n/a | def conjugate(self): |
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261 | n/a | """Conjugate is a no-op for Reals.""" |
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262 | n/a | return +self |
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263 | n/a | |
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264 | n/a | Real.register(float) |
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265 | n/a | |
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266 | n/a | |
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267 | n/a | class Rational(Real): |
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268 | n/a | """.numerator and .denominator should be in lowest terms.""" |
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269 | n/a | |
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270 | n/a | __slots__ = () |
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271 | n/a | |
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272 | n/a | @property |
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273 | n/a | @abstractmethod |
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274 | n/a | def numerator(self): |
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275 | n/a | raise NotImplementedError |
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276 | n/a | |
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277 | n/a | @property |
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278 | n/a | @abstractmethod |
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279 | n/a | def denominator(self): |
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280 | n/a | raise NotImplementedError |
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281 | n/a | |
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282 | n/a | # Concrete implementation of Real's conversion to float. |
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283 | n/a | def __float__(self): |
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284 | n/a | """float(self) = self.numerator / self.denominator |
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285 | n/a | |
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286 | n/a | It's important that this conversion use the integer's "true" |
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287 | n/a | division rather than casting one side to float before dividing |
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288 | n/a | so that ratios of huge integers convert without overflowing. |
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289 | n/a | |
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290 | n/a | """ |
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291 | n/a | return self.numerator / self.denominator |
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292 | n/a | |
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293 | n/a | |
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294 | n/a | class Integral(Rational): |
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295 | n/a | """Integral adds a conversion to int and the bit-string operations.""" |
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296 | n/a | |
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297 | n/a | __slots__ = () |
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298 | n/a | |
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299 | n/a | @abstractmethod |
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300 | n/a | def __int__(self): |
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301 | n/a | """int(self)""" |
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302 | n/a | raise NotImplementedError |
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303 | n/a | |
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304 | n/a | def __index__(self): |
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305 | n/a | """Called whenever an index is needed, such as in slicing""" |
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306 | n/a | return int(self) |
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307 | n/a | |
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308 | n/a | @abstractmethod |
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309 | n/a | def __pow__(self, exponent, modulus=None): |
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310 | n/a | """self ** exponent % modulus, but maybe faster. |
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311 | n/a | |
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312 | n/a | Accept the modulus argument if you want to support the |
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313 | n/a | 3-argument version of pow(). Raise a TypeError if exponent < 0 |
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314 | n/a | or any argument isn't Integral. Otherwise, just implement the |
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315 | n/a | 2-argument version described in Complex. |
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316 | n/a | """ |
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317 | n/a | raise NotImplementedError |
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318 | n/a | |
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319 | n/a | @abstractmethod |
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320 | n/a | def __lshift__(self, other): |
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321 | n/a | """self << other""" |
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322 | n/a | raise NotImplementedError |
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323 | n/a | |
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324 | n/a | @abstractmethod |
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325 | n/a | def __rlshift__(self, other): |
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326 | n/a | """other << self""" |
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327 | n/a | raise NotImplementedError |
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328 | n/a | |
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329 | n/a | @abstractmethod |
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330 | n/a | def __rshift__(self, other): |
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331 | n/a | """self >> other""" |
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332 | n/a | raise NotImplementedError |
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333 | n/a | |
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334 | n/a | @abstractmethod |
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335 | n/a | def __rrshift__(self, other): |
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336 | n/a | """other >> self""" |
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337 | n/a | raise NotImplementedError |
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338 | n/a | |
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339 | n/a | @abstractmethod |
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340 | n/a | def __and__(self, other): |
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341 | n/a | """self & other""" |
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342 | n/a | raise NotImplementedError |
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343 | n/a | |
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344 | n/a | @abstractmethod |
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345 | n/a | def __rand__(self, other): |
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346 | n/a | """other & self""" |
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347 | n/a | raise NotImplementedError |
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348 | n/a | |
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349 | n/a | @abstractmethod |
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350 | n/a | def __xor__(self, other): |
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351 | n/a | """self ^ other""" |
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352 | n/a | raise NotImplementedError |
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353 | n/a | |
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354 | n/a | @abstractmethod |
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355 | n/a | def __rxor__(self, other): |
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356 | n/a | """other ^ self""" |
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357 | n/a | raise NotImplementedError |
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358 | n/a | |
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359 | n/a | @abstractmethod |
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360 | n/a | def __or__(self, other): |
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361 | n/a | """self | other""" |
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362 | n/a | raise NotImplementedError |
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363 | n/a | |
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364 | n/a | @abstractmethod |
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365 | n/a | def __ror__(self, other): |
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366 | n/a | """other | self""" |
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367 | n/a | raise NotImplementedError |
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368 | n/a | |
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369 | n/a | @abstractmethod |
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370 | n/a | def __invert__(self): |
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371 | n/a | """~self""" |
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372 | n/a | raise NotImplementedError |
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373 | n/a | |
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374 | n/a | # Concrete implementations of Rational and Real abstract methods. |
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375 | n/a | def __float__(self): |
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376 | n/a | """float(self) == float(int(self))""" |
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377 | n/a | return float(int(self)) |
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378 | n/a | |
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379 | n/a | @property |
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380 | n/a | def numerator(self): |
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381 | n/a | """Integers are their own numerators.""" |
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382 | n/a | return +self |
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383 | n/a | |
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384 | n/a | @property |
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385 | n/a | def denominator(self): |
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386 | n/a | """Integers have a denominator of 1.""" |
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387 | n/a | return 1 |
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388 | n/a | |
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389 | n/a | Integral.register(int) |
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