"PageRank is computed by solving an equation of 500 million variables and two bi... | Hacker News

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euroclydon on Sept 27, 2009 | parent | context | favorite | on: Google's first press release

"PageRank is computed by solving an equation of 500 million variables and two billion terms."

Does it take 500 million variables to compute my Pagerank of 3 when there are only 32 sites that link to it? How many of those 500 million variables are 0 or null?

jacquesm on Sept 27, 2009 | [–]

Pagerank is a funny algorithm, think of it as a problem in gravitation, every page affects the pagerank of every other page.

You compute the equilibrium and then normalize the results.

There are a bunch of optimizations that you can apply in order to speed things up bit it is still quite computationally expensive.

ludwig on Sept 28, 2009 | | [–]

For an overview of PageRank, you should check out http://www.ams.org/featurecolumn/archive/pagerank.html

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