Probably someone else can give a better answer, but if I remember correctly ParMetis relies on certain random number generator that makes it produce different partitions for different runs. I think this was fixed in the ParMetis that --download-parmetis installs, but if I am not wrong you are not using that version. This would explain what you get.
Jose > El 16 ene 2022, a las 11:37, Varun Hiremath <varunhirem...@gmail.com> > escribió: > > Hi All, > > I am using SLEPc to compute eigenvalues and MUMPS for factorization. > > Please find attached: > 1) A simple test program slepc_eps_mumps_test.cpp that reads a given PETSc > matrix and computes the smallest eigenvalues using MUMPS for factorization > 2) An example PETSc matrix MatA of size 581343 rows (sending in .gz format > via Google drive link, please extract it "gunzip MatA.gz" before using). You > should be able to reproduce this issue with any other matrix of a similar or > bigger size. > > I notice that when I run the attached test program in parallel with the > attached test matrix the MUMPS statistics printed (using the -eps_view option > in the command line) change with every run. > > This is how I run the test: > $ mpiexec -n 24 ./slepc_eps_mumps_test.o -nev 5 -f MatA -eps_view > and for example, the output of this includes the following MUMPS stats > ... > PC Object: (st_) 24 MPI processes > type: lu > out-of-place factorization > tolerance for zero pivot 2.22045e-14 > matrix ordering: external > factor fill ratio given 0., needed 0. > Factored matrix follows: > Mat Object: 24 MPI processes > type: mumps > rows=581343, cols=581343 > package used to perform factorization: mumps > total: nonzeros=348236349, allocated nonzeros=348236349 > MUMPS run parameters: > SYM (matrix type): 0 > ... > > I ran this test 10 times as follows and got a different number of nonzeros > (line highlighted above ) reported in each run. (If you save the full output > and compare, you will notice many other differences, but I wouldn't have > expected the nonzeros to change with every run.) > > $ for i in `seq 1 10`; do echo "run $i :-----"; mpiexec -n 24 > ./slepc_eps_mumps_test.o -nev 5 -f MatA -eps_view | grep -A 1 "factorization: > mumps"; done > > run 1 :----- > package used to perform factorization: mumps > total: nonzeros=354789915, allocated nonzeros=354789915 > run 2 :----- > package used to perform factorization: mumps > total: nonzeros=359811101, allocated nonzeros=359811101 > run 3 :----- > package used to perform factorization: mumps > total: nonzeros=354834871, allocated nonzeros=354834871 > run 4 :----- > package used to perform factorization: mumps > total: nonzeros=354830397, allocated nonzeros=354830397 > run 5 :----- > package used to perform factorization: mumps > total: nonzeros=353942929, allocated nonzeros=353942929 > run 6 :----- > package used to perform factorization: mumps > total: nonzeros=354147241, allocated nonzeros=354147241 > run 7 :----- > package used to perform factorization: mumps > total: nonzeros=354980083, allocated nonzeros=354980083 > run 8 :----- > package used to perform factorization: mumps > total: nonzeros=354980083, allocated nonzeros=354980083 > run 9 :----- > package used to perform factorization: mumps > total: nonzeros=354214219, allocated nonzeros=354214219 > run 10 :----- > package used to perform factorization: mumps > total: nonzeros=355894047, allocated nonzeros=355894047 > > Can somebody please explain what causes these differences in MUMPS stats? > > Thanks, > Varun > MatA.gz > > <slepc_eps_mumps_test.cpp>
