Re: [eigen] [Fwd: eigen cwise] unexpected performance regression with eigen's cwise()

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On Wednesday 19 August 2009 20:01:26 Rohit Garg wrote:
> A freind of mine who is using eigen for his code, hit this unexpected
> speed bump. I have no idea why.

Undefined behavior, as the program tries to access blah[SIZE] and 
blah[SIZE+1]. Assuming that your friend wrote j instead of i, does he have all 
optimizations (and SSE) enabled?

Otherwise, the unstable branch works fine for me:

your friend's "cwiseop":
 14.66s, 14.91s, 14.65s

 7.67s, 7.67s, 7.74s

(Core2 Quad 2.4 GHz, gcc 4.4.0, fedora 11, eigen unstable)

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