[Cppqed-support] Eigen

[Andras V. <and...@ui...>]

Dear Raimar,
I have now completed migration to Eigen3, and it seems to work fine. I have
pushed the feature branch named Eigen to SourceForge (only core & scripts
affected).
Could you please fetch the branch and update cmake such that it looks for
Eigen3 instead of FLENS? If not found, DO_NOT_USE_EIGEN should be set.
Two points to note:
* EIGEN_NO_DEBUG should be set for release mode but the documentation of
Eigen states that it gets set if NDEBUG is set, so in principle we do not
need to care about this.
* Under ARCH (and Ubuntu also, I think), Eigen3 gets installed under a
directory called eigen3, so that the main include files can be pulled in as
#include <eigen3/Eigen/Core>
for example. However, in the documentation they only use
#include <Eigen/Core>
It would be nice to have this latter, especially because this eigen3
directory will not necessarily exist in all distributions. Hence, if Eigen3
is found, this eigen3 directory should be put into the include path.
Thanks, with best regards,
András


Dr. Andras Vukics
Institute for Theoretical Physics
University of Innsbruck