> total: nonzeros=1830, allocated nonzeros=29280 > total number of mallocs used during MatSetValues calls =1830
There is something wrong with your preallocation or matrix assembly. You should see zero mallocs for efficient assembly. http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#efficient-assembly satish On Wed, 7 Jul 2010, Xuan YU wrote: > Hi, > > I finite difference Jacobian approximation for my TS model. The size of the > vector is 2500. I got the following info with(-ts_view): > > type: beuler > maximum steps=50 > maximum time=50 > total number of nonlinear solver iterations=647 > total number of linear solver iterations=647 > SNES Object: > type: ls > line search variant: SNESLineSearchCubic > alpha=0.0001, maxstep=1e+08, minlambda=1e-12 > maximum iterations=50, maximum function evaluations=10000 > tolerances: relative=1e-08, absolute=1e-50, solution=1e-08 > total number of linear solver iterations=50 > total number of function evaluations=51 > KSP Object: > type: gmres > GMRES: restart=30, using Classical (unmodified) Gram-Schmidt > Orthogonalization with no iterative refinement > GMRES: happy breakdown tolerance 1e-30 > maximum iterations=10000, initial guess is zero > tolerances: relative=1e-05, absolute=1e-50, divergence=10000 > left preconditioning > using PRECONDITIONED norm type for convergence test > PC Object: > type: ilu > ILU: out-of-place factorization > 0 levels of fill > tolerance for zero pivot 1e-12 > using diagonal shift to prevent zero pivot > matrix ordering: natural > factor fill ratio given 1, needed 1 > Factored matrix follows: > Matrix Object: > type=seqaij, rows=1830, cols=1830 > package used to perform factorization: petsc > total: nonzeros=1830, allocated nonzeros=1830 > total number of mallocs used during MatSetValues calls =0 > not using I-node routines > linear system matrix = precond matrix: > Matrix Object: > type=seqaij, rows=1830, cols=1830 > total: nonzeros=1830, allocated nonzeros=29280 > total number of mallocs used during MatSetValues calls =1830 > not using I-node routines > > > 50 output time step takes me 11.877s. So I guess there is something not > appropriate with my Jacobian Matrix. Could you please tell me how to speed up > my code? > > Thanks! > > Xuan YU > xxy113 at psu.edu > > > >
