[petsc-dev] Configure fails on macOS with MKL

[Satish Balay]

I've added $MKLROOT/lib/ to search path for MKL. Thanks for the report.

https://bitbucket.org/petsc/petsc/commits/7fe016461159234c29eaa106eb46d0bf81683f36

Wrt libiomp5.dylib - its an intel compiler library - so its found when
using icc,icpc [as you describe below].

I guess it doesn't work when building with clang?

Intel MKL advisor is the authoritative tool for such checks..

https://software.intel.com/en-us/articles/intel-mkl-link-line-advisor/

it says:

 -L${MKLROOT}/lib -Wl,-rpath,${MKLROOT}/lib -lmkl_intel_lp64 -lmkl_intel_thread -lmkl_core -lmkl_blacs_mpich_lp64 -liomp5 -lpthread -lm -ldl

So it suggests using -liomp5 - but doesn't say - its not a clang library. Not sure how to deal with this automatically.
Your current approach of using LDFLAGS is appropriate [workarround].

Satish

On Wed, 21 Dec 2016, Pierre Jolivet wrote:

> Hello,
> There are some issues when using (most recent versions of) the MKL on macOS:
> 1) the correct path to libmkl_*.dylib is now $MKLROOT/lib/, but this is not taken into account by the build system
> 
> diff --git a/config/BuildSystem/config/packages/BlasLapack.py b/config/BuildSystem/config/packages/BlasLapack.py
> index 43597e2..017ed12 100644
> --- a/config/BuildSystem/config/packages/BlasLapack.py
> +++ b/config/BuildSystem/config/packages/BlasLapack.py
> @@ -217,7 +217,7 @@ class Configure(config.package.Package):
>          mkl_blacs_32=[]
>        if useCPardiso or usePardiso:
>          self.logPrintBox('BLASLAPACK: Looking for Multithreaded MKL for C/Pardiso')
> -        for libdir in [os.path.join('lib','64'),os.path.join('lib','ia64'),os.path.join('lib','em64t'),os.path.join('lib','intel64'),'64','ia64','em64t','intel64',
> +        for libdir in [os.path.join('lib','64'),os.path.join('lib','ia64'),os.path.join('lib','em64t'),os.path.join('lib','intel64'),'64','ia64','em64t','lib','intel64',
>                         os.path.join('lib','32'),os.path.join('lib','ia32'),'32','ia32','']:
>            if not os.path.exists(os.path.join(dir,libdir)):
>              self.logPrint('MKL Path not found.. skipping: '+os.path.join(dir,libdir))
> 
> 2) Once this is fixed, it is assumed that libiomp5.dylib is in the same folder as libmkl_intel_thread.dylib (which is wrong), or at least visible to the linker. Thus, the configure will fail because it can’t find libiomp5.dylib, unless explicitly using —CXX=icpc and —CC=icc, or —LDFLAGS=-L${PATH_TO_LIBIOMP5}
> 
> I don’t know if you care enough to fix this (I’m guessing there aren’t that many macOS users compiling PETSc with MKL support but without the Intel compilers), but just in case… 
> Thanks,
> Pierre