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Mathematics at Google

research.google.com

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Re: Mathematics at Google

#2
My day-to-day programming consists so much of process and simple boolean logic that I hardly ever use math more challenging than 1 + 1 and 1 != 0. It's great to review how math can greatly influence the potential of your code.

Re: Mathematics at Google

#4
Do they still heavily rely on PageRank? With the amount of traffic data Google has, I would expect more statistical approaches based on what users click (rather than graph algorithms based on how the web is linked) to be the backbone for ranking their results.

Re: Mathematics at Google

#5
post #4

Do they still heavily rely on PageRank? With the amount of traffic data Google has, I would expect more statistical approaches based on what users click (rather than graph algorithms based on how the web is linked) to be the backbone for ranking their results.

PageRank is definitely still used, although it's doubtfully the sole determinant of ranking results. See http://jeremykun.wordpress.com/2011/06/21/googles-page-rank-...

Re: Mathematics at Google

#6
post #3

Look at the slide entitled Gmail (5), and compare the picture with the first graph on my blog post http://jeremykun.wordpress.com/2011/08/11/the-perceptron-and... It just goes to show, Google steals content without attribution just like everyone else.

Wait, they just used your graph and didn't even contact you about it?

Re: Mathematics at Google

#7
post #3

Look at the slide entitled Gmail (5), and compare the picture with the first graph on my blog post http://jeremykun.wordpress.com/2011/08/11/the-perceptron-and... It just goes to show, Google steals content without attribution just like everyone else.

It's one guy who happens to work for Google, rather than the whole company.

Re: Mathematics at Google

#8
post #5
post #4

Do they still heavily rely on PageRank? With the amount of traffic data Google has, I would expect more statistical approaches based on what users click (rather than graph algorithms based on how the web is linked) to be the backbone for ranking their results.

PageRank is definitely still used, although it's doubtfully the sole determinant of ranking results. See http://jeremykun.wordpress.com/2011/06/21/googles-page-rank-...

I agree with your statement, but I'm confused by the story in the link... I haven't come across a message board that doesn't use rel="nofollow" in a few years (that NYT article is from 2010). How would these negative reviews bolster his PageRank?

Re: Mathematics at Google

#9
This is a fantastic publication! I do some part-time mathematics tutoring, and kids are always wondering where math is used in "real life". Since kids are all familiar with Google, this should resonate with them.

Re: Mathematics at Google

#10
post #2

My day-to-day programming consists so much of process and simple boolean logic that I hardly ever use math more challenging than 1 + 1 and 1 != 0. It's great to review how math can greatly influence the potential of your code.

> simple boolean logic

A SAT solver[1] can automatically figure out a range of acceptable solutions for your conditions. 'I want this goal, is there a way to make that happen?' Security people love this. SMT solvers are even crazier[2] and can automatically determine solutions to linear equations or inequalities (this comes in handy when analyzing loops). Z3 has an online version at [3].

Also, if you have a lot of nasty cascaded if-statements, a K-map[4] and espresso[5] can reduce those down to a minimal set of branches. Note that fewer branches means fewer branch prediction penalties, which means faster code!

[1] http://en.wikipedia.org/wiki/Boolean_satisfiability_problem

[2] http://media.tumblr.com/tumblr_m8ywn1iesH1r6uu3b.gif

[3] http://rise4fun.com/z3/tutorial/guide

[4] http://en.wikipedia.org/wiki/Karnaugh_map

[5] http://embedded.eecs.berkeley.edu/pubs/downloads/espresso/in... and ftp://ftp.cs.man.ac.uk/pub/amulet/balsa/other-software/espresso-ab-1.0.tar.gz

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