How does Google pull a search result from an index over a hundred

prediction and optimization

>>7944620
magic

>>7944620
>Aren't search algorithms completed in exponential time?
Not if they're done well.

>>7944620
Google "information retrieval" and "fuzzy search"

>>7944622
Haha

>>7944620
they have a HUGE NxN matrix (let's call it C) of almost only 0 and a few 1, where N is the number of internet pages. if there is a 1 in the (i,j) position it means the the page j has a link pointing to the page j.
This matrix represent the connectivity structure of the entire web.


Then we want to give a score of "relevance" to every page.
We assume that a link pointing to the site j contribute psoitively to the score of j, the contribution of every link is weighted by the score of the page it came from and the number of link in this same page.

We introduce the matrix Q NxN where q(i,j)=c(i,j)/Nj where c(i,j) is the coeficient (i,j) in the matrix C, and Nj the number of link present in the page j.

So the N dimensional vector r of the score of all the pages, verify the equation r=Qr .
So r is just an eigenvector of Q.
It may be possible that Q doesn't have an eigenvalue of 1, so we slightly modify it. I won't details everything, but google made this part of the algorithm public, so you can find it.

>>7944643
oh, and of course to find the eigenvector they use the power iteration method, a direct method would take billions of years with such large matrix.

https://en.wikipedia.org/wiki/Power_iteration

>>7944622
This
Every full moon an intern is sacrificed on Google's server. The fresh blood grants them unearthly powers from the Old Gods.

>>7944643
Got it, math

>>7944643

but

1. the matrix changes every day

2. when you search for a word, you don't search for a link

>>7944620
Theres a udacity course where you build a search engine

>>7944667
>most valuable corporation in the entire world
>all the top minds of computer science
>countless phD and post docs
>proprietary algos left and right
>limitless money to run limitless servers that might as well be infinity

b-but its hard...
>kill yourself

>>7944704

>most valuable corporation in the entire world
>all the top minds of computer science
>countless phD and post docs
>proprietary algos left and right
>limitless money to run limitless servers that might as well be infinity

yet can't even solve the syracuse problem

>>7944715
>limitless money to run limitless servers that might as well be infinity
Pretty sure you could solve collatz with infinity servers.

File: ZyO3L9PXIrg.jpg (30KB, 735x439px) Image search: [Google]

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>>7944696
>complains about image
>on an imageboard

>>7944728
I read that as "lolcatz"

>>7944736
> posts pedo crap
> in a non-pedo allowed website

>>7944746
>pedo

Bitch is like 14 and the main character never even fucked her. I did masturbate to pics of her though.

Definitely not pedo, you moron.

Why do people who don't watch anime at least 10 hours a day come to 4chan?

>>7944746
>complains about """""pedo"""""
>picture doesn't even have nudity

>>7944762
whats 4chan gotta do with anime you pedo shit ?

>>7944772
>Daily reminder that 4chan's first boards were /a/-Anime General, /b/-Anime Random and /c/-Anime Cute

Oh wait, I forgot. You are like 12 and just started coming to 4chan last week. Yeah, you wouldn't know shit about fuck right?

4chan boards may now involve a bunch of other subjects but the sticky cum that holds us all together, regardless of board, is anime. This is a website for people who like anime to come and discuss things that are not anime, with other people who like anime.

If you don't like anime you don't belong here. There is always reddit for the 4chan-lite experience.

>>7944774
No, I've been here long enough to know that only about 10 boards here is about your retarded manchildren anime-pedo garbage. Rest of the +50 boards are NOT about anime-pedo garbage, which /sci/ happens to be a part of.

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>>7944784
You sure are trolling us anon. Keep up the good work.

File: Hinata-chan.jpg (131KB, 1280x720px) Image search: [Google]

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>>7944784
But it is still about anime.

It is like going to your board game club and you start talking about politics or science or technology. You are all there to play some board games, but there will always be discussion about other stuff.

That is 4chan, except with anime. Everyone comes here for the anime, but you always end up discussing something else instead because anime gets old a bit fast.

The first board I ever became a daily poster in was /a/ but soon enough I was roaming /g/ and /r9k/ and now the only board I even touch is /sci/. Still, I have a heavy as fuck folder of anime girls and when people mention anime in /sci/ I always join in.

Basically, you don't know shit about 4chan culture. And if you were even a bit smart you would have taken a hint because of how the header .gif is always an anime girl or something related to anime and anime girls.

>>7944772
Must feel bad being a complete newfag transient from reddit.

>>7944799
Not as bad as being a weeaboo faggot.

>>7944794
> can't look up the boards and check its true
fuck off back to your >>>/a/nime-pedophilia board, this board is called /sci/, NOT /a/

>>7944817
>calls someone a weeaboo without knowing what it actually means
Keep going, this is hilarious.

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>>7944819

>>7944827
B T F O
T
F
O

>>7944827
> please read the rules
> There are boards dedicated to a variety of topics, from Japanese animation and culture to videogames, music, and photography.

I wish you've read the rules yourself. Then maybe you would stop flooding /sci/ with your anime-pedophilia garbage

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>>7944864
>How does Google pull a search result from an index over a hundred million gigabytes in a fraction of a second? Aren't search algorithms completed in exponential time?
>Not a /sci/ topic

File: I+second+you+bro+i+_eb7092b9c7958822f7621f920d3a3c6f[1].jpg (204KB, 1099x1232px) Image search: [Google]

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>>7944874
> flooding the thread with dozens of irrelevant manchlidren anime-pedo garbage is science
:^)

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>>7944884
>Flooding the thread with dozens of irrelevant manchild posts is science.
:^)

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>>7944899
You keep proving yourself to be the ultimate shitposter as none of your images or comments are related to this topic and not even related to this board.
Go back to your pedophile shithole and don't visit a science board ever again.
>>>ret/a/rd

>>7944620
>Aren't search algorithms completed in exponential time?

Inverted index lookup is average case constant time if using a hash table.

This is assuming single-word queries though.

>>7944746
>everything that isn't gay is pedo crap
>>>/lgbt/

>>7944928
>>>/a/utism

>>7944935
did you notice that the only person flooding /sci/ with shit was (You) ?

>>7945029
nope. I don't even have an anime reaction image spamming folder since i'm not a pedophile

>>7945041
well lully for you then
toodles!

>>7945041
>stop enjoying things!!!
you're literally /a/-tier autistic

>>7945290
> if I generalize cartoons for pedophile manchildren with "things" maybe i can trick them of having a point.
As much as its fun to see you desperately drowning in your own autism, I think its time you get back to your pedophilia board shithead
>>>/a/
>>>/mlp/

>>7944704
What you don't get is that it doesn't answer OP's question.

>>7944620
>Aren't search algorithms completed in exponential time?
No, not even naive ones.

>>7944827
You need an ad blocker.

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Not topic-relevant but I try my luck though.

Do any of you know the source of pic related?
I tried to look this book up, didn't get any clue over Google.

>>7944620
It doesn't.

It has a short term memory that holds all the most recent searches for x amount of time. Since humans tend to "trend", this type of short term memory system is far better than one where the search of the entire data base is actually made every time someone searches.