# How are matrices typically stored in computer systems? [closed]

How are matrices usually represented within computer systems? For example, Google stores extremely large matrices on their servers for maintaining an index of web pages and determining the importance of those web pages.

Not necessarily in Google's case, in what data format are "living" matrices (read: not stuck in code) commonly stored?

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A useful keyword here might be "sparse matrix". –  Zhen Lin Feb 25 '12 at 16:44
I think this is off topic, perhaps some other site on the SE network would fit better. –  Asaf Karagila Feb 25 '12 at 17:17
Perhaps you're right, I'll try StackOverflow –  Calvin Froedge Feb 25 '12 at 17:27
Having realized this, how about deleting your question? I think you have the power to do so, at least so long as nobody has answered it. (BTW, I doubt very much that google's way of storing their matrix is “typical” in any way, shape or form.) –  Harald Hanche-Olsen Feb 25 '12 at 17:55
Or try here: scicomp.stackexchange.com –  yasmar Feb 25 '12 at 18:15
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## closed as off topic by Asaf Karagila, jspecter, Kannappan Sampath, Alex Becker♦, Ｊ. Ｍ.Mar 24 '12 at 14:10

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There are two main ways of storing matrices in computer RAM. Those are columnwise and rowwise. Columnwise way works by decomposing matrix to columns and store subsequent element of columns underincreasing memory locations np.:

$$[c_{11}, c_{12}, c_{13}], [c_{21}, c_{23}, c_{24}]$$

is stored in continues block of memory like this: $$c_{11}, c_{12}, c_{13}, c_{21}, c_{23}, c_{24}$$

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These are storage schemes for dense matrices. –  user2468 Feb 25 '12 at 20:18