Andrew Barnert wrote: > On Sep 19, 2019, at 19:18, Richard Higginbotham higgi...@gmail.com wrote: > > It's not really constant though. > > It’s really hard to have a discussion when all of your posts are all > > replies, but > you don’t give us any clue what you’re replying to. There are multiple > responses from > multiple people since your last email, each with multiple paragraphs covering > multiple > subjects. So I have no idea what “it” refers to. Or what “though” is > challenging. I'm just trying to respond to everyone using the mail.python.org interface. I'll use the quote function to make it clearer (I hope).
> But I think what you’re trying to do is argue that hash tables don’t work. No, I think I provided experimental evidence to show that there is a time cost for looking up hashes and that can increase when the size of the tables increase. Where that actually comes from internally doesn't really matter. You have to execute that constant hash for every item in the A set. If you can computer your hash in 1 picosecond that is still len(A) * 1 picoseconds at best and theoretically only. The numbers I referenced above with 0.3ms versus 0.5 ms could lead one to think that it's not just a factor of the size of A. That could be due to how timit does things or many other factors. So of course I'm wondering if that is also impacting my routines. Or it is related to the difference between C and pure python. I'm not just scoffing that it doesn't match what I want. The number of values in A is the limiting factor for set operations. That's why I didn't use large values for A and small values for B. Past that the time it takes to make a set from a list is the other limiting factor. I'm not proposing to replace the set library. If the user has two sets use the set functions, they are plenty fast. If the user doesn't have sets then my list functions are faster than converting to sets and then back again, at least after the size of the lists has reached some threshold. _______________________________________________ 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/QRY6QFPE2RMRRK7IU4U7FSNAABXMI7YS/ Code of Conduct: http://python.org/psf/codeofconduct/
