We currently do not have a transfer to host setup for cusparse. I have a preliminary version here https://gitlab.com/petsc/petsc/-/tree/stefanozampini/feature-mataij-create-fromcoo
Should be ready in a couple of days for review. Il giorno mar 20 ott 2020 alle ore 14:37 Matthew Knepley <[email protected]> ha scritto: > On Tue, Oct 20, 2020 at 4:40 AM Héctor Barreiro Cabrera < > [email protected]> wrote: > >> El jue., 15 oct. 2020 a las 23:32, Barry Smith (<[email protected]>) >> escribió: >> >>> >>> We still have the assumption the AIJ matrix always has a copy on the >>> GPU. How did you fill up the matrix on the GPU while not having its copy >>> on the CPU? >>> >>> My strategy here was to initialize the structure on the CPU with dummy >> values to have the corresponding device arrays allocated. Ideally I would >> have initialized the structure on a kernel as well, since my intention is >> to keep all data on the GPU (and not hit host memory other than for >> debugging). But since the topology of my problem remains constant over >> time, this approach proved to be sufficient. I did not find any problem >> with my use case so far. >> >> One thing I couldn't figure out, though, is how to force PETSc to >> transfer the data back to host. MatView always displays the dummy values I >> used for initialization. Is there a function to do this? >> > > Hmm, this should happen automatically, so we have missed something. How do > you change the values on the device? > > Thanks, > > Matt > > >> Thanks for the replies, by the way! I'm quite surprised how responsive >> the PETSc community is! :) >> >> Cheers, >> Héctor >> >> >>> Barry >>> >>> When we remove this assumption we have to add a bunch more code for >>> CPU only things to make sure they properly get the data from the GPU. >>> >>> >>> On Oct 15, 2020, at 4:16 AM, Héctor Barreiro Cabrera < >>> [email protected]> wrote: >>> >>> Hello fellow PETSc users, >>> >>> Following up my previous email >>> <https://lists.mcs.anl.gov/pipermail/petsc-users/2020-September/042511.html>, >>> I managed to feed the entry data to a SeqAICUSPARSE matrix through a CUDA >>> kernel using the new MatCUSPARSEGetDeviceMatWrite function (thanks Barry >>> Smith and Mark Adams!). However, I am now facing problems when trying to >>> use this matrix within a SNES solver with the Eisenstat-Walker method >>> enabled. >>> >>> According to PETSc's error log, the preconditioner is failing to invert >>> the matrix diagonal. Specifically it says that: >>> [0]PETSC ERROR: Arguments are incompatible >>> [0]PETSC ERROR: Zero diagonal on row 0 >>> [0]PETSC ERROR: Configure options PETSC_ARCH=win64_vs2019_release >>> --with-cc="win32fe cl" --with-cxx="win32fe cl" --with-clanguage=C++ >>> --with-fc=0 --with-mpi=0 --with-cuda=1 --with-cudac="win32fe nvcc" >>> --with-cuda-dir=~/cuda --download-f2cblaslapack=1 --with-precision=single >>> --with-64-bit-indices=0 --with-single-library=1 --with-endian=little >>> --with-debugging=0 --with-x=0 --with-windows-graphics=0 >>> --with-shared-libraries=1 --CUDAOPTFLAGS=-O2 >>> >>> The stack trace leads to the diagonal inversion routine: >>> [0]PETSC ERROR: #1 MatInvertDiagonal_SeqAIJ() line 1913 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\mat\impls\aij\seq\aij.c >>> [0]PETSC ERROR: #2 MatSOR_SeqAIJ() line 1944 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\mat\impls\aij\seq\aij.c >>> [0]PETSC ERROR: #3 MatSOR() line 4005 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\mat\INTERF~1\matrix.c >>> [0]PETSC ERROR: #4 PCPreSolve_Eisenstat() line 79 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\ksp\pc\impls\eisens\eisen.c >>> [0]PETSC ERROR: #5 PCPreSolve() line 1549 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\ksp\pc\INTERF~1\precon.c >>> [0]PETSC ERROR: #6 KSPSolve_Private() line 686 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c >>> [0]PETSC ERROR: #7 KSPSolve() line 889 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c >>> [0]PETSC ERROR: #8 SNESSolve_NEWTONLS() line 225 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\snes\impls\ls\ls.c >>> [0]PETSC ERROR: #9 SNESSolve() line 4567 in >>> C:\cygwin64\home\HBARRE~1\PETSC-~1\src\snes\INTERF~1\snes.c >>> >>> I am 100% positive that the diagonal does not contain a zero entry, so >>> my suspicions are either that this operation is not supported on the GPU at >>> all (MatInvertDiagonal_SeqAIJ seems to access host-side memory) or that I >>> am missing some setting to make this work on the GPU. Is this correct? >>> >>> Thanks! >>> >>> Cheers, >>> Héctor >>> >>> >>> > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > > https://www.cse.buffalo.edu/~knepley/ > <http://www.cse.buffalo.edu/~knepley/> > -- Stefano
