[Users] Need help building Einstein Toolkit: clang: error: unsupported option '-fopenmp'

[Roland Haas]

Hello Murray,

clang (in particular Apple's version delivered in OSX) is not fully
supported by the ET (due to, at least historically, no OpenMP support,
no paired Fortran compiler).

Please see the initial section of:

https://github.com/nds-org/jupyter-et/blob/master/CactusTutorial.ipynb

for how to use the ET on OSX using homebrew or macports.

If you have a Fortran compiler installed you can try disabling openmp
by setting OPENMP=no in your option list. I strongly advise consulting
the link I provided above and following the (tested and
verified) instructions there in particular if this is your first time
using the toolkit.

Yours,
Roland

> Hi All,
> 
> Thanks so much for making the Einstein Toolkit software available!
> 
> I'm using the CactusTutorial.ipynb that I got from your site. I'm trying to
> build ET on my 2015 Macbook Pro running OS 10.15.7.
> 
> I'm stuck at the cell (after) *Building the Einstein Toolkit* .
> I modified that cell to get past issues with zlib . The cell now looks like:
> 
> %%bash
> export ZLIB_DIR=/usr/local/opt/zlib/lib
> export LDFLAGS="-L/usr/local/opt/zlib/lib"
> export CPPFLAGS="-I/usr/local/opt/zlib/include"
> export PKG_CONFIG_PATH="/usr/local/opt/zlib/lib/pkgconfig"
> ./simfactory/bin/sim build -j2 --thornlist ../einsteintoolkit.th
> 
> Running that cell eventually stops with the errors
> 
> COMPILING CactusBase/CoordBase/src/Domain.c
> COMPILING configs/sim/bindings/build/ADMCoupling/cctk_ThornBindings.c
> clang: error: unsupported option '-fopenmp'
> make[3]: *** [Domain.c.o] Error 1
> make[2]: *** [make.checked] Error 2
> make[1]: *** [/Users/murray/Cactus/configs/sim/lib/libthorn_CoordBase.a] Error 2
> make[1]: *** Waiting for unfinished jobs....
> clang: error: unsupported option '-fopenmp'
> make[3]: *** [cctk_ThornBindings.c.o] Error 1
> make[2]: *** [cctk_Bindings/make.checked] Error 2
> make[1]: *** [/Users/murray/Cactus/configs/sim/lib/libthorn_ADMCoupling.a]
> Error 2
> make: *** [sim] Error 2
> 
> 
> Can you help? I'm confused by the error message coming from clang, since
> the ET seems to use gcc, but my attempt to force gcc, by including the
> exports below, made no difference:
> 
> export CC=gcc-10
> export CXX=gcc-10
> 
> I really appreciate any help you are able to provide!
> 
> Thank you.
> 
> Murray (Wolinsky)
> ______________________________________________________
> 
> Additional (likely irrelevant) notes:
> 
> I used brew to install the prerequisites. It seemed to have gone
> more-or-less ok.
> 
> Brew did issue a somewhat concerning message regarding hdf5:
> 
> ==> Pouring hdf5-1.12.0_1.catalina.bottle.1.tar.gz  
> 
> Warning: hdf5 dependency gcc was built with a different C++ standard
> 
> library (libstdc++ from clang). This may cause problems at runtime.
> 
> 
> But it didn't provide any guidance into fixing the potential problem. Itried
> 
> 
> brew reinstall hdf5
> 
> 
> and brew no longer complains.
> 
> 
> I also had some issues with the subversion installation. But I don't think
> they're responsible for my current problem.
> 
> 
> Also, when I did the step *Configuring SimFactory for your machine*, I got
> the output:
> 
> Here we will define some necessary Simulation Factory defaults.
> 
> Determining local machine name: mw-3.local
> 
> --------------------SUMMARY--------------------:
> 
> 
> [default]
> user            = murray
> email           = murray
> allocation      = NO_ALLOCATION
> 
> ------------------END SUMMARY------------------:
> 
> Contents successfully written to
> /Users/murray/Cactus/repos/simfactory2/etc/defs.local.ini
> 
> 
> which looks OK, but the NO_ALLOCATION message seems like it might be of concern?


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