On Feb 17, 2014, at 8:27 AM, Matthias Felleisen <matth...@ccs.neu.edu> wrote:
> That is odd. Do share the code so others can inspect it. Will do. > (The trick with this assignment is to make the two matrixes large enough so > that they fit, barely fit, don't fit in certain levels of the memory > hierarchy. This is perhaps 10-year old thinking but I am sure it hasn't > gotten much better.) Yes, I suspect it has something to do with memory hierarchies. One of the algorithms in question is Strassen’s, which is most straightforwardly applied to power-of-2 matrix sizes, so I’ve been running on sizes 4, 8, 16, 32, 64, 128, 256, 512, 1024, and 2048. Somewhere around 128 Strassen’s algorithm beat out the naive O(n^3) divide-and-conquer algorithm, and I extrapolate that around 4096 it will beat out the straightforward O(n^3) nested-for-loops matrix-multiplication algorithm… but even size 2048 has been taking hours or days to run. Stephen Bloch sbl...@adelphi.edu
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