Use TSComputeDefaultJacobian instead of SNESComputeDefaultJacobian if you want to use TS objects only.
> ierr = > TSComputeDefaultJacobian(ts,t,CV_Y,&J,&J,&flag,PETSC_NULL);CHKERRQ(ierr); > ierr = MatGetColoring(J,MATCOLORINGSL,&iscoloring);CHKERRQ(ierr); > ierr = MatFDColoringCreate(J,iscoloring,&matfdcoloring);CHKERRQ(ierr); > ierr = ISColoringDestroy(iscoloring);CHKERRQ(ierr); ...you missed this > ierr = MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode > (*)(void))f,(void*)&appctx);CHKERRQ(ierr); > ierr = MatFDColoringSetFromOptions(matfdcoloring);CHKERRQ(ierr); > ierr = TSSetRHSJacobian(ts,J,J,TSDefaultComputeJacobianColor,matfdcoloring); Shri > ----- "Xuan YU" <xxy113 at psu.edu> wrote: > > ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,N,N,10,PETSC_NULL,&J);CHKERRQ(ierr); ierr = MatAssemblyBegin(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); ierr = MatAssemblyEnd(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); ierr = SNESComputeJacobian(ts_snes,CV_Y,&J,&J,&flag);CHKERRQ(ierr); ierr = MatGetColoring(J,MATCOLORINGSL,&iscoloring);CHKERRQ(ierr); ierr = MatFDColoringCreate(J,iscoloring,&matfdcoloring);CHKERRQ(ierr); ierr = MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))f,(void*)&appctx);CHKERRQ(ierr); ierr = MatFDColoringSetFromOptions(matfdcoloring);CHKERRQ(ierr); ierr = TSSetRHSJacobian(ts,J,J,TSDefaultComputeJacobianColor,matfdcoloring); > > These are the Jacobian related codes. > > > > > > > > On Jul 7, 2010, at 1:51 PM, Satish Balay wrote: total: nonzeros=1830 > > mallocs used during MatSetValues calls =1830 > > > > Looks like you are zero-ing out the non-zero structure - before > > assembling the matrix. > > > > Are you calling MatZeroRows() or MatZeroEntries() or something else - > > before assembling the matrix? > > > > Satish > > > > On Wed, 7 Jul 2010, Xuan YU wrote: > > > > I made a change: ierr = > > MatCreateSeqAIJ(PETSC_COMM_SELF,N,N,5,PETSC_NULL,&J);CHKERRQ(ierr); > > > > Time of the code did not change much, and got the info: > > Matrix Object: > > type=seqaij, rows=1830, cols=1830 > > total: nonzeros=1830, allocated nonzeros=36600 > > total number of mallocs used during MatSetValues calls =1830 > > not using I-node routines > > > > > > > > On Jul 7, 2010, at 12:51 PM, Satish Balay wrote: > > > > 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 1830. 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 > > > > > > > > > > > > > > > > Xuan YU (??) > > xxy113 at psu.edu > > > > > > > > > > > > > > > > Xuan YU ( ?? ) xxy113 at psu.edu > > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20100707/19a1f9cd/attachment-0001.htm>
