On Wed, May 17, 2023 at 9:02 AM Fleischli Benno HSLU T&A < benno.fleisc...@hslu.ch> wrote:
> Dear PETSc developers > > I am creating a very large parallel sparse matrix (MATMPIAIJ) with PETSc. > I write this matrix to disk. > The number of non-zeros exceeds the maximum number a 32-bit integer can > hold. > When I read the matrix from disk i get an error because there was an > overflow in the nz number. > (see petsc-3.18.4/src/mat/impls/aij/seq/aij.c:4977) > > Obviously I could compile PETSc with 64bit integers > (--with-64-bit-indices). > But I wanted to ask if there is another way. Because the total number of > nonzeros nz is the only numer that exceeds the 32bit limit. > It would not be efficient to use 64bit integers everywhere just because of > this single number. > Integers tend to be a small part of the overall storage. How much does it increase the maximum overall storage for your problem? Thanks, Matt > This how I configured PETSc: > > ./configure --download-fblaslapack --download-hpddm --download-hypre > --with-debugging=0 > COPTFLAGS='-O3 -march=native -mtune=native' CXXOPTFLAGS='-O3 -march=native > -mtune=native' > FOPTFLAGS='-O3 -march=native -mtune=native' --with-scalar-type=real > (--with-mpi-dir=/home/benno/Libraries/openMPI) > > > > Kind Regards > > Benno > > > > ________________________________ > > > *Hochschule Luzern Technik & Architektur* > Institute for Mechanical Engineering and Energy Technology > > Competence Center Fluid Mechanics and Numerical Methods > > > *Benno Fleischli* > MSc in Mechanical Engineering / BSc in Electrical Engineering > > Wissenschaftlicher Mitarbeiter > > benno.fleisc...@hslu.ch > <https://webmail.hslu.ch/owa/redir.aspx?C=rM5K5xPd_kKJmyojcJXaG18BaXM9wM8IqSslYJQen5H6HtdiNS2KtWNFL89yfRdRtW-Oa6xCXTk.&URL=mailto%3akatrina.kemp%40hslu.ch> > > -- 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/>