mpi.h: No such file or directory about nccl-tests HOT 6 CLOSED

The $MPI_HOME variable in the Makefileassumes includes are in $MPI_HOME/include and libraries are in $MPI_HOME/lib. In most cases, /usr/include/mpi is just a link, and the real MPI installation is in /usr/lib/openmpi (both includes and library). Setting MPI_HOME=/usr/lib/openmpi would solve the problem.

Another simple solution is to add /usr/include/mpi to the path of g++ includes :

export CPLUS_INCLUDE_PATH=/usr/include/mpi:$CPLUS_INCLUDE_PATH

And if the libraries are not found (cannot find -lmpi), we can also tell g++ where to find libraries :

export LIBRARY_PATH=/usr/lib/openmpi/lib:$LIBRARY_PATH

(but usually there is a link in /usr/lib/libmpi.so so it shouldn't be needed)

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Hello,
I am using a Jetson Nano cluster and /usr/lib/openmpi does not exist. It seems the mpi is installed because I get the following output when I run mpirun --version:

mpirun (Open MPI) 2.2.1

Report bugs to http://www.open-mpi.org/community/help/

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On ARM platforms, the path to Open MPI might be something like /usr/lib/aarch64-linux-gnu/openmpi.

mpicc -show would show where MPI includes and library are located, then you can use MPI_HOME or CPLUS_INCLUDE_PATH/LIBRARY_PATH to make sure g++ finds them well.

Please note however that NCCL is not targeted at Jetson Nano so I would not expect it to work.

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I was able to find it under /usr/lib/aarch64-linux-gnu/openmpi However when running the command mpirun -np 16 ./build/all_reduce_perf -b 32M -e 128M -f 2 -t 1 -g 1 -c 0 the following error ouputs:

./build/all_reduce_perf: error while loading shared libraries: libnccl.so.2: cannot open shared object file: No such file or directory

But from my understanding this should be found under the NCCL_HOME variable?

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If you did not install NCCL on the system (just compiled it in your home directory), you need to set LD_LIBRARY_PATH :

export LD_LIBRARY_PATH=$NCCL_HOME/build/lib:$LD_LIBRARY_PATH

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Closing old issues. Please open another one if you are still seeing issues.

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