Saddamkles

Well, yes and no. With a straight-up hash set, you're keeping set_size * bits_per_element bits plus whatever the overhead of the hash table is in memory, which might not be tenable for very large sets, but with a Bloom filter that has eg. ~1% false positive rate and an ideal k parameter (number of hash functions, see eg. the Bloom filter wiki article) you're only keeping ~10 bits per element completely regardless of element size because they don't store the elements themselves or even their full hashes – they only tell you whether some element is probably in the set or not, but you can't eg. enumerate the elements in the set. As an example of memory usage, a Bloom filter that has a false positive rate of ~1% for 500 million elements would need 571 MiB (noting that although the size of the filter doesn't grow when you insert elements, the false positive rate goes up once you go past that 500 million element count.)

Lookup and insertion time complexity for a Bloom filter is O(k) where k is the parameter I mentioned and a constant – ie. effectively O(1).

Probabilistic set membership queries are mainly useful when you're dealing with ginormous sets of elements that you can't shove into a regular in-memory hash set. A good example in the wiki article is CDN cache filtering:

Nearly three-quarters of the URLs accessed from a typical web cache are "one-hit-wonders" that are accessed by users only once and never again. It is clearly wasteful of disk resources to store one-hit-wonders in a web cache, since they will never be accessed again. To prevent caching one-hit-wonders, a Bloom filter is used to keep track of all URLs that are accessed by users. A web object is cached only when it has been accessed at least once before, i.e., the object is cached on its second request.

Which example do you mean?

If you meant my user ID example, you'd prepopulate the bloom filter with existing user IDs on eg. service startup or whatever, and then update the filter every time a new user ID is added – keeping in mind that the false positive rate will grow as more are added, and that at some point you may need to create a new filter with a bigger backing bit array

https://knowyourmeme.com/memes/saddam-husseins-hiding-place

That's definitely not what they're most useful for. I mean, you probably can use a bloom filter for implementing spell check, but saying that's where they're most useful severely misses the point of probabilistic set membership queries.

Bloom filters and their relatives are great when you have a huge set of values – eg. 100s of millions of user IDs in some database – and you want to have a very fast way of checking whether some value might be in that set, without having to query the database. Naturally this assumes that you've prepopulated a bloom filter with whatever values you need to be checking.

If the result of the bloom filter query is "nope", you know that the value's definitely not in the set, but if the result is "maybe" then you can go ahead and double-check by querying the database. This means that the vast majority of checks don't have to hit that slow DB at all, and even though you'll get some false positives this'll still be much much much faster than having to go through that DB every time.

Do you want to learn about probabilistic data structures?

• maybe
• no

I stopped playing the game after I ran into the first bullet sponge boss, tried several times to beat it with my all-stealth character and realized I'd probably have to start over

This post is Hamas! The students are also Hamas!

lol, conservatives experiencing consequences for their actions. Wouldn't that be the day.

Right, and which part of that makes saying "the problem isn't just the US" untrue? If anything that underlines the fact that everybody should be chipping in more

Musk, the employees said, was not pleased with Tinucci’s presentation and wanted more layoffs. When she balked, saying deeper cuts would undermine charging-business fundamentals, he responded by firing her and her entire 500-member team.

The dude's a petulant child. No wonder conservatives fawn over him.

And I am perfectly fine with that.

You wouldn't be an asshole otherwise. Maybe some beautiful day you'll realise being an insufferable twat might not be the best approach to life, but I'm not going to hold my breath.

The US isn't the only one though, it's the same everywhere except the countries that Russians have occupied.

It's like world leaders want Russia to win; making a show of donating insignificant amounts of old weapons systems they had lying around, but not actually doing enough to ensure Ukraine's victory.

You're not wrong, you're just an asshole

And not just any Paul Atreides but the OG one.

I know I'm supposed to hate the '84 Dune with a burning passion, but I just love it. Sure it's weird and campy in places, but that's why I like it.

This reeks of someone who uses the word "woke" unironically

Edit: I couldn't help my curiosity. Turns out not only do they use the word "woke" unironically, they seem to think that grown men dating teenagers is A-OK, because of course they do:

Imagine my utter lack of surprise.