Hi all, I get some randomness when solving certain equation systems with MUMPS. When I repeatedly solve the attached equation system by ksp example 10, I get different solution vectors and therefore different residual norms.
jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.15502e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.15502e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.17364e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.17364e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.17364e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.15502e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.15502e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.17364e-12 jac@jac-VirtualBox:~/data/rep/petsc/src/ksp/ksp/examples/tutorials$ mpiexec -np 4 ./ex10 -f ./1.mat -rhs ./1.vec -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps Number of iterations = 1 Residual norm 4.15502e-12 It seems to be depending on a combination of number of processes and the equation system. I used GCC 7.2.0, Intel 16, MUMPS 5.1.1 / 5.1.2 (with & without metis/parmetis), openMPI 2.1.2. All with the same results. PETSc configuration is the current maint branch: ./configure --download-mumps --with-debugging=0 --COPTFLAGS="-O3" --CXXOPTFLAGS="-O3" --FOPTFLAGS="-O3" --with-scalapack Using "--download-fblaslapack --download-scalapack" didnt make a difference neither. Can anyone reproduce that issue? Thanks and kind regards, Volker
mumps-eqs.tar.gz
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