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A comment on Matrix Multiplication. Parent comment

Re:Matrix Multiplication by snovv_crash on Friday November 25, 2016 @11:39AM (#13037886)
I really like that. And matrix * matrix would just have to be 3D, with a whole cube of taps. Sure, not easy to illustrate, but the concept extends well. It also makes it more obvious what the complexity of the operation is.
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Re:Matrix Multiplication by im3w1l on Friday November 25, 2016 @04:36PM (#13040029)
Actually the complexity of matrix multiplication is not known. Current best is n^2.37
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Re:Matrix Multiplication by dangom on Saturday November 26, 2016 @07:42AM (#13043224)
There is a proven lower bound [1], though.

[1] http://epubs.siam.org/doi/abs/10.1137/0218052

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Re:Matrix Multiplication by justinpombrio on Friday November 25, 2016 @11:56AM (#13038017)
In a little more detail:

Look at the animation in the article, after the second matrix has been rotated and put on top of the first one. Then flip its top up so the two matrices are orthogonal. Finally, rotate the whole thing 90 degrees to the left (rotating along the axis that goes from the top of the page to the bottom of the page). Now you can see that the result will be a 2x3 matrix. And the values in each spot will be the sum of the products beneath it.

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