| Re: [eigen] Speed issues, array min,max |
[ Thread Index |
Date Index
| More lists.tuxfamily.org/eigen Archives
]
Your example is flawed, since it is trivial enough for the compiler to
optimize away (almost) entirely. Add EIGEN_ASM_COMMENT("begin/end...");
lines and have a look at the generated assembler to see what I mean.
If the values of the vectors are not known at compile-time (and not the
same for each iteration), you should get essentially the same assembler
with Eigen and your hand-coded version -- but with less lines of code.
Christoph
On 05.10.2015 15:21, Gabriel wrote:
Why is this test code so slow for eigen3
(see simple main)
*http://pastebin.com/11XzzNFs*
Output here with gcc 4.9.2 , full optimization is turned on:
*Eigen3: time: 0.150045 ms **
**Seperate: time: 0.000131 ms **
*
So it seems that it is not beneficial to use eigen for this simple index
calculations, but why?
Thanks for the help! :-)
--
Dipl. Inf., Dipl. Math. Christoph Hertzberg
Universität Bremen
FB 3 - Mathematik und Informatik
AG Robotik
Robert-Hooke-Straße 1
28359 Bremen, Germany
Zentrale: +49 421 178 45-6611
Besuchsadresse der Nebengeschäftstelle:
Robert-Hooke-Straße 5
28359 Bremen, Germany
Tel.: +49 421 178 45-4021
Empfang: +49 421 178 45-6600
Fax: +49 421 178 45-4150
E-Mail: chtz@xxxxxxxxxxxxxxxxxxxxxxxx
Weitere Informationen: http://www.informatik.uni-bremen.de/robotik