Limit : Raise NotImplemented error when limit approaches zoo #14458
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sympy/series/limits.py
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| @@ -128,7 +128,9 @@ def __new__(cls, e, z, z0, dir="+"): | |||
| z = sympify(z) | |||
| z0 = sympify(z0) | |||
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| if z0 is S.Infinity: | |||
| if z0 is S.ComplexInfinity: | |||
| raise NotImplementedError() | |||
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Not the right place for this. The construction of an inert Limit object should not raise a NotImplementedError. The user isn't asking SymPy to compute the limit. The Limit object may be needed to express some logic in a formula, to be returned to a user, or to be processed by a user-written complex-limit-evaluating function.
What is not implemented is the evaluation of such limits, and that is in the doit method.
sympy/series/limits.py
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| @@ -163,6 +163,9 @@ def doit(self, **hints): | |||
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| e, z, z0, dir = self.args | |||
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| if z0 is S.ComplexInfinity: | |||
| raise NotImplementedError() | |||
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There should be some text in NotImplementedError, otherwise how will the user know that the problem is with zoo and not with something else in the formula (like, in the expression e)? For example, NotImplementedError("Limits at complex infinity are not implemented")
Fixes #14456