Using Eigen3 in device code under OpenACC

Accelerated Computing HPC Compilers Legacy PGI Compilers
1

Does anyone have a good example where they use Eigen3 in device code offloaded to the device via OpenACC?

2

Seems another Eigen user had some of the same issues. No issues with PGI in this case.

For the record.
First issue.
PGC+±W-0155-External and Static variables are not supported in acc routine - _ZTVSt9exception (/nobackupp16/swbuild/dkokron/NFLOW-CHEM/nflow-chem/test/source_miniapp/mainOpenACC.cpp: 63)
std::exception::exception():
3, include “exception”
32, include “exception”
6, include “exception.h”
63, Generating implicit acc routine seq
PGC+±W-0155-External and Static variables are not supported in acc routine - _ZTVSt9exception (/nobackupp16/swbuild/dkokron/NFLOW-CHEM/nflow-chem/test/source_miniapp/mainOpenACC.cpp: 63)
std::exception::exception() [subobject]:
0, Generating implicit acc routine seq
PGC+±W-0155-External and Static variables are not supported in acc routine - _ZTVSt9exception (/nobackupp16/swbuild/dkokron/NFLOW-CHEM/nflow-chem/test/source_miniapp/mainOpenACC.cpp: 57)
std::bad_alloc::bad_alloc():

c++filt _ZTVSt9exception
vtable for std::exception

Their solution was to hack on the Eigen code. Commenting line 70 in Eigen/src/Core/util/Memory.h also got rid of some of the errors

Second issue.
PGC+±W-0155-Compiler failed to translate accelerator region (see -Minfo messages) (/nobackupp16/swbuild/xxxNFLOW-CHEM/nflow-chem/test/source_miniapp/mainOpenACC.cpp: 234)
T2 Eigen::internal::evaluator<Eigen::PlainObjectBase<Eigen::Array<double, (int)11, (int)1, (int)0, (int)11, (int)1>>>::packet<(int)0, double __attribute((vector_size(2*sizeof(double)))) >(long, long) const:
7, include “kinetics.hpp”
25, include “nflow.hpp”
16, include “Core”
260, include “CoreEvaluators.h”
234, Generating implicit acc routine seq
Generating acc routine seq
Generating Tesla code
609, Accelerator restriction: unsupported operation: VLD
234, Accelerator restriction: an unsupported operation was found

I’m compiling with PGI 20.4 with -fast -O3 -DNDEBUG -acc -ta=tesla:cc70 -Minfo=accel
Figuring VLD meant VectorLoad, I disabled vectorization in the Eignen code via -DEIGEN_DONT_VECTORIZE=1 compilation flag.

Both of these ‘fixes’ allowed the compile to complete without errors.