17.09.21 05:23, Steven D'Aprano пише: >>>> factorial(23) == better_factorial(23) > False > > The problem is that since floats only have about 17 significant figures > or so, once you get to 23! the gamma function doesn't have enough > precision to give an exact answer. Of course that's easily fixable. > (Only call gamma if the input argument is a float.)
It is not even easily fixable. First, the resulting function which uses different algorithms for integers and non-integers can be non-monotonic. Second, factorial() supports large arguments for which gamma() raises an overflow error. Third, it will have non-uniform computational complexity. The time of calculating gamma() is virtually constant, but the time of calculating factorial() grows with increasing argument. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/CW7DINDWDML373EC3OYNME4KEEC7XU2S/ Code of Conduct: http://python.org/psf/codeofconduct/
