Assertion error inside HDAGG::partialSparsification for Hdagg_SpTRSV example about aggregation HOT 8 OPEN

Thanks, can you please send a PR?

from aggregation.

I haven't diagnosed the root cause of error, but simply skipped the cases that calls partialSparsification in order to compile that example program. For example SpTrSv_LL_HDAGG doesn't call sparsification so still runs, but SpTrSv_LL_Tree_HDAGG breaks. However the inspection time of HDAGG is many times slower than Tree_HDAGG, presumably due to lack of sparsification.

from aggregation.

One clue: The same SpTRSV_runtime.cpp example from the older repo https://github.com/BehroozZare/HDagg-benchmark (as of commit 948b38f) runs fine without array-bound errors. So it must be due to some updates in between.

from aggregation.

Got it, thanks.
I think HDagg repo is more updated than this for the HDagg algorithm.

from aggregation.

Hi @cheshmi I found the problem with this repo --

The find_package(OpenMP) in the top-level cmake file is disabled:

This is probably fine when compiled as a subproject of Sympiler (where OpenMP is found one level higher); but when compiling this aggregation repo as a standalone project, the ENABLE_OPENMP macro and OpenMP flags won't get defined. Then, inside the HDAGG::partialSparsification function:

Both bins and tid will be set to 1, causing a bug when the user wants parallel partitioning.

Uncommenting find_package(OpenMP) fixes the bug. Or maybe using the HAS_PARENT condition to optionally include dependencies.

One the other hand, in the older HDagg-benchmark repo, there is no ENABLE_OPENMP switch, and bins is always set to omp_get_num_threads(), so no such bug.

from aggregation.

More unit tests for the HDagg procedure (sparsification, grouping, partitioning, ungrouping...) might help prevent future bugs? In the current Catch_tests there seems to be only one test for the simple levelset sptrsv, but not more advanced partitionings like LBC or HDagg. And the test is disabled in cmake file.

from aggregation.

The current GitHub workflow runs lbc_demo and sptrsv_demo, but not Hdagg_SpTRSV (the executable for SpTRSV_runtime.cpp).

If you add lines like

cmake --build ${{github.workspace}}/build --target Hdagg_SpTRSV
${{github.workspace}}/build/example/Hdagg_SpTRSV`, 

you should see the error message in GitHub actions.

from aggregation.

OK I saw that find_package(OpenMP) was disabled by the commit 5b88309 , presumably to ensure compatibility with the parent Sympiler directory.

May using

if(LBC_IS_TOPLEVEL)
    find_package(OpenMP)
endif()

to avoid duplication. Although I think duplicately calling find_package(OpenMP) is also fine...

from aggregation.