examples for getting started with omega_h

The following instructions apply to the SCOREC RedHat 7 systems with NVIDIA GPUs. Specific instructions are given for Pascal GPUs (e.g., in the blockade and pachisi systems).

First build the dependencies for execution with the Kokkos backend using CUDA.

Kokkos: https://github.com/SCOREC/pumi-pic/wiki/Building-and-Running-on-SCOREC-RHEL7#kokkos

Omega_h: https://github.com/SCOREC/pumi-pic/wiki/Building-and-Running-on-SCOREC-RHEL7#omega_h

Alternatively, for debugging purposes you can build Omega_h in serial without kokkos:

https://github.com/SCOREC/pumi-pic/wiki/Building-and-Running-on-SCOREC-RHEL7#building-omega_h-in-serial-for-debugging

Note, you'll still need to set export oh=/path/to/omega_h/install accordingly for the omegah_examples build.

Setup the environment.

module load cuda/10.1 gcc mpich cmake 
# use the environment variable set in the omega_h build
export CMAKE_PREFIX_PATH=$oh:$CMAKE_PREFIX_PATH
export MPICH_CXX=$kksrc/bin/nvcc_wrapper

Clone the repo, run cmake, then build.

git clone [email protected]:SCOREC/omegah_examples.git
mkdir build-ohExamples-pascal
cd !$
cmake ../omegah_examples -DCMAKE_CXX_COMPILER=mpicxx
make

Run ctest to run the examples:

ctest

Setup the environment.

module load gcc cmake 
# use the environment variable set in the omega_h build
export CMAKE_PREFIX_PATH=$oh:$CMAKE_PREFIX_PATH

Clone the repo, run cmake, then build.

git clone [email protected]:SCOREC/omegah_examples.git
mkdir build-ohExamples-serial
cd !$
cmake ../omegah_examples -DCMAKE_CXX_COMPILER=g++
make

Run ctest to run the examples:

ctest

Note, any example using MPI will not compile.

Create a new source file from an existing one:

cd omegah_examples
cp firstOrderAdjacency.cpp foo.cpp

Add the new file to the build and test system cmake files:

testing.cmake - execution commands for examples, add mpi_test(foo_2D 1 ./foo ${CMAKE_SOURCE_DIR}/meshes/tri8.osh) to start with, then modify as the new example is implemented

CMakeLists.txt - defines compile and link commands for examples; add example(foo foo.cpp)

Ensure that the new example compiles and runs:

# setup the environment as described above
cd build-ohExamples-pascal
make
ctest