Re: [eigen] Matrix-Matrix Multiplication gives incorrect results (C++11, sometimes) |

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*To*: eigen@xxxxxxxxxxxxxxxxxxx*Subject*: Re: [eigen] Matrix-Matrix Multiplication gives incorrect results (C++11, sometimes)*From*: Torbjörn Klatt <opensource@xxxxxxxxxxxxxxxxxx>*Date*: Thu, 18 Sep 2014 12:21:34 +0200

Never mind. Everything's fine. :-) BTW: My minimal example is not complete and missleading. Sorry for the noise. On Thu, 18.09.2014 10:52:22 Torbjörn Klatt wrote: > Hi all, > > I'm using dynamic row-major Eigen3 matrices. Within my code I'm generating a > (n-1)xn matrix (Q_pre) and post-prefix it with a zero-row to get a nxn > matrix Q. Afterwards I'll need to square it, which gives me QQ. (see > 'problematic.cpp' in [1]) > > However, the resulting matrix QQ has its "last" (bottom-right) entry > incorrectly computed. (see 'OUT: problematic' in [1]) > > I composed a minimal example and compiled it with the same compiler (and > options) just to discover that everything goes fine. > > Am I missing something? Neither of the tested compilers (GCC 4.8.3, 4..9.1, > Clang 3.4.2, 3.5.0) on a 64bit openSUSE 13.1 all with Eigen3 3.2.2 has a > different behaviour. Nor does any of the compilers complain about anything > when run with `-Wall -Wextra -Wpedantic -g -O0 -std=c++11`. > > Kind regards, > Torbjörn Klatt > > > [1] https://gist.github.com/torbjoernk/70731289e5a8f054bc67

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