feature/omptarget

[jxy]

The OpenMP target backend here is still a work in progress. We welcome any suggestions.

As of now this port uses a few Intel extensions, contains hacks specifically for Intel architectures, and it only works on Intel GPUs.

For a quick test, try

cmake\
        -DCMAKE_BUILD_TYPE=RELEASE\
        -DQUDA_TARGET_TYPE=OMPTARGET\
        -DQUDA_DOWNLOAD_USQCD=on\
        -DQUDA_QMP=on\
        -DQUDA_QIO=on\
        -DQUDA_DIRAC_DEFAULT_OFF=on\
        -DQUDA_DIRAC_STAGGERED=on\
        -DQUDA_PRECISION=8\
        -DQUDA_RECONSTRUCT=4\
        -DQUDA_FAST_COMPILE_REDUCE=on\
        -DQUDA_FAST_COMPILE_DSLASH=on\
        -DQUDA_BUILD_NATIVE_LAPACK=off\
        -DCMAKE_CXX_COMPILER=mpic++\
        -DCMAKE_C_COMPILER=mpicc\
        ../quda