More efficient dot product function.

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Andrew
Andrew 2013-7-1
Hello,
I am just wondering if anyone knows a more efficient function than the dot from MATLAB. I am running a very robust simulator that needs to compute over 3 million dot products (and possibly even more for different cases) throughout the course of the simulation. This leads to the dot products taking up the second most amount of time out of the many functions called by the simulator. I suspect that a lot of the time spent in the dot function is being wasted checking to make sure the vectors are properly sized.
Thanks for your help!

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Hugo
Hugo 2013-7-1
Are you using the function dot(x,y) ?
If that's so, better use
x'*y (assuming that x and y are column vectors)
In my computer, x'*y is twice faster than sum(x.*y) and twenty times faster than dot(x,y). Good luck.

更多回答（1 个）

Shashank Prasanna
BSXFUN is the most efficient way to do element wise dot operations:
http://www.mathworks.com/help/matlab/ref/bsxfun.html

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