[mlpack] CMakeList adjustments for compiling Mlpack with Armadillo using openblas

[Ryan Curtin]

On Wed, Dec 25, 2013 at 10:22:36PM +0000, Steenwijk, Martijn wrote:
> Hi all,
> 
> Today I tried to compile mlpack using Armadillo using openblas. It
> appeared that CMakeLists needed some adjustments, which are referred
> to here (https://gist.github.com/bdsatish/5648571;  linking against
> openblas library, and inclusion of include/lib dirs in the
> CMakeLists). As Armadillo recommends to build using openblas, it might
> be a good idea to catch this situation in CMake.

Hello Martijn,

Unless I'm mistaken, Armadillo will automatically use OpenBLAS if
available.  If Armadillo isn't automatically linking against OpenBLAS I
don't think the right solution is to disable ARMA_USE_WRAPPER but
instead to find out why Armadillo isn't automatically finding OpenBLAS.

If you're not using ARMA_USE_WRAPPER, then everything you do that uses
Armadillo will need to be linked against each dependency of Armadillo --
depending on your configuration this could mean -llapack -lblas -lhdf5
-larpack -lmkl (and so forth).

But this does lead to an important point: can we detect when
ARMA_USE_WRAPPER is disabled, and then detect which libraries we need to
link against?  I'm sure the answer is yes, but it will be a long time
until I have a chance to look into it.  Would you be interested in doing
that?  If not, I'll open a Trac ticket that someone can eventually take.

Thanks,

Ryan

-- 
Ryan Curtin    | "Lots of respectable people have been hit by
ryan at ratml.org | trains."  - Penny